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• 3m men in the US and 330,000 men in the UK are living with prostate cancer
• The standard test used to diagnose prostate cancer is inaccurate
• This inaccuracy causes anxiety in men and leads to unnecessary treatments
• Standard therapies for prostate cancer can result in incontinence and impotence
• Two new studies describe procedures that promise significant improvements in diagnosis and treatment

Prostate cancer is increasing in significance worldwide. In many industrialized countries such as the US and the UK, it is one of the most common cancers and among the leading causes of cancer deaths. In developing countries it may be less common, but its incidence and mortality rates have been on the rise. In the US there are some 3m men living with the disease.  It is expected that in 2017, 161,000 new cases of prostate cancer will be diagnosed in the US, and 27,000 men will die from it. In the UK, there are some 330,000 men living with prostate cancer; each year around 47,000 men are diagnosed with the disease, and each year some 11,000 die from it, which equates to one every hour. Worldwide, there are an estimated 1.6m new cases of prostate cancer, and 366,000 prostate cancer deaths annually, making it the most commonly diagnosed cancer in men and the seventh leading cause of male cancer death.
 

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The prostate and prostate cancer

The prostate is a small gland in men, which is located below the bladder and above the rectum. The urethra, which is the tube that carries urine and semen out of the body through the penis, goes through the centre of the prostate. In younger men the prostate is about the size of a walnut, but in older men it can be much larger. Symptoms of prostate cancer include persistent burning, difficult, frequent, uncontrolled or bloody urination in the absence of any infection. The average age of onset is 65 to 69. It is particularly prevalent in African-Caribbean men: affecting I in 4, and killing I in 12, which is double the rate for that of Caucasian men. The main risk factor is age: 80% of all men diagnosed with prostate cancer are over 65. Between 5% and 9% of cases occur in men with a family history of prostate, breast or ovarian cancer. Environmental factors are unclear, but rates of prostate cancer are lower in less urbanised societies, and rates rise when people move to a more westernised diet and lifestyle.

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The prostate-specific antigen (PSA) test

In the 1980s a simple and cheap blood test was introduced to detect prostate cancer in its earliest, most curable, stage. In the video below Professor Karol Sikora, a cancer expert, describes the PSA test. Although used to detect prostate cancer, it is not a test for prostate cancer, and as a consequence, it has unresolved challenges. The most significant arises because the test is not accurate enough to either rule out or confirm the presence of cancer. Indeed, it is possible for PSA levels to be elevated when cancer is not present, and not to be elevated when it is present. More than 65% of men with elevated PSA levels do not have cancer. Excessive reliance on the test may lead to unnecessary interventions, while insufficient reliance may cause cancers to be missed.
 

 

Biopsies
 

A biopsy will often be recommended if a PSA test is high. It may also be recommended if a digital rectal examination (DRE) reveals a lump or some other abnormality in the prostate. The most commonly used biopsy for diagnosing prostate cancer is the trans-rectal ultrasound-guided prostate biopsy (TRUS-biopsy). This is a surgical procedure, in which tissue is removed from the prostate for microscopic examination. Each year, over 100,000 prostate biopsies are carried out in the UK and 1m in Europe.
 
75 to 80% of men who have TRUS-biopsies have no cancerous cells, and therefore did not need the biopsy. 20 to 25% do have cancerous cells, but a large percentage of these do not need any treatment because the cancers are slow growing.  A 2014 paper by the Harvard School of Public Health estimates that only 3% of men suspected of prostate cancer have an aggressive tumor requiring immediate intervention.
 
Further, doctors cannot tell from a biopsy whether cancerous cells are aggressive and need treatment, or whether they are developing slowly and do not require treatment. This creates confusion and anxiety among men, which prompts a percentage to opt for treatment even though the overwhelming majority do not need it. 25% of older men who elect to have treatment will become incontinent or impotent as a result, despite the fact that they did not need the treatment.
 

Active surveillance

 
In a significant proportion of men, prostate cancer cells grow slowly and never pose a serious risk to health and longevity. Evidence suggests that early treatment with either surgery or radiation does not reduce mortality rates, but leaves a significant percentage of men with urinary or erectile problems and other adverse effects. As a result, more men are willing to manage their condition by active surveillance, in which doctors monitor low-risk cancers closely and consider treatment only when the condition appears to make threatening moves toward growing and spreading. These men choose to live with prostate cancer until it advances, sometimes avoiding potentially life-altering side effects for several years. Active surveillance is a powerful solution to the problem of over-diagnosis and overtreatment.
 

New studies promise significantly improved management

Prostate cancer lags behind other cancers in diagnosis, treatment and research funding. But this is beginning to change. Over the past year, findings of two clinical studies promise significant improvements in the management of the condition.

The first, published in 2017 in the Lancet, describes a process, which uses MRI-guided biopsies to improve the accuracy of prostate cancer diagnosis, and spares those who do not have aggressive cancers from undergoing an unnecessary biopsy, so reducing the confusion and anxiety which prostate patients often experience.

The second, published in 2016 in the Lancet Oncology, describes findings of a laser-activated drug derived from bacteria found at the bottom of the sea that attacks and kills prostate cancer cells without either removing or destroying the prostate gland. This is significant because it avoids the potential adverse effects of surgery and radiotherapy, which can render patients incontinent and/or impotent. 
 

The multi-parametric MRI

The 2017 Lancet study used an advanced type of MRI scan, known as a multi-parametric MRI (MP-MRI), which in addition to recording the shape and size of the prostate, also assesses the blood flow through the gland. Led by Dr Hashim Ahmed of University College London, the study was comprised of more than 500 British men with suspected prostate cancer. Results suggest that using the MP-MRI to triage men would safely reduce the number needing a primary biopsy by about 27%, and substantially improve the detection of clinically significant cancers. If subsequent TRUS-biopsies were directed by MP-MRI findings, up to 18% more cases of clinically significant cancers might be detected compared with the standard pathway of TRUS-biopsy for all.
 

A paradigm shift in prostate cancer treatment

The second study compared the safety and effectiveness of a new therapy called vascular-targeted photodynamic therapy (VTP, also known as TOOKAD), with active surveillance in men with low-risk prostate cancer. It funded by STEBA Biotech, which holds the commercial licence for the therapy. Photodynamic therapy (PDT) is not new, and has been used to treat skin and other cancers where light can easily penetrate.  VTP therapy, however, is viewed as a paradigm shift in prostate cancer care. It involves injecting a light-sensitive drug (padeliporfin or WST11) into the bloodstream, and then activating it with a laser to destroy cancerous tissue.  The benefit of this approach is damage to healthy prostate tissue is minimised, reducing the risk of side effects.
 

Findings

The study was comprised of 413 men at low risk of prostate cancer, and carried out across 47 treatment sites in 10 European countries, most of which were performing VTP therapy for the first time. Only men classified with low-risk cancer were included in this study. Participants were randomly assigned either to VTP therapy or active surveillance. At the end of two years, of the 196 men who received the VTP treatment, about half showed no signs of the disease, compared with 13.5% of those given standard care. Only 6% of the VTP group later needed radical treatment, compared with 30% of active surveillance patients. VTP treatment also doubled the average time of cancer progression from 14 to 28 months. Findings suggest that 49% of patients treated with VTP therapy went into complete remission compared with 13.5% in the control group.

A third of the VTP group experienced side effects compared to only 10 of the active surveillance group. Notwithstanding, the study concluded that, “VTP therapy is a safe, effective treatment for low-risk, localised prostate cancer, which might allow more men to consider a tissue-preserving approach and defer or avoid radical therapy”. Patient monitoring will continue in order to ascertain whether the cancer stays away. Further studies should help to understand better which cancers VTP  treatment is most appropriate for so that men can make more informed treatment decisions.

Study enhanced by MRI scanning
 

The study was conducted with people at low risk of prostate cancer. Those at very low risk are better off with no treatment and no adverse-effects. Professor Mark Emberton of University College London, the lead author of the study, believes the therapy will be most useful in patients in the “grey zone”, between low and high risk. “The fact that the treatment was performed so successfully by non-specialist centres in various health systems is really remarkable”, says Emberton because the lack of complication suggests that the treatment protocol is safe, and relatively easy to scale.

At the beginning of the study MRI scans were not universally available, and Emberton believes MRI scanning as suggested by the Ahmed 2017 study will have a significant positive effect on prostate cancer treatment in the future. When carrying out biopsies without guidance from MRI scans researchers had to guess where in the prostate the cancer was; so biopsies were sub-optimal. “If they were to do the study now, with the help of MRI scans, they could hit the cancerous parts of the prostate rather than going in blind and the results would be much better,” says Emberton.
 

Takeaways

 
These two recent studies are potential “game changers”. They promise to significantly enhance the management of prostate cancer and substantially reduce the uncertainty and anxiety, as well as the risks of the life altering side effects of treatment, experienced by millions of men living with the disease.

• Cancer results when stem cells divide and mutate uncontrollably
• Whether this is predominantly the result of intrinsic or extrinsic factors is unclear
• Some experts say 65% of cancers result from intrinsic factors and are unavoidable
• Other experts say most cancers result from extrinsic factors and are avoidable
• Cancer strategy should not hide behind ‘bad luck’
• Resources need to be allocated more smartly to prevent cancer

Is cancer the result of bad luck and unavoidable, or is it self-inflicted and prevented by simple lifestyles choices? Two 2015 studies arrive at strikingly different conclusions.
 
One, carried out by researchers from the John Hopkins Kimmel Cancer Centre and published in January 2015 in the journal Science, suggests that two thirds of cancers result from bad luck. Another, carried out by researchers from the Stony Brook Cancer Centre in New York and published in December 2015 in the journal Nature rebuts the findings of the Science paper, and suggests that 70 to 90% of cancer risk is self-inflicted and therefore can be avoided.

Which is right? And, why should this concern us?
 

Cancer

Cancer is a complex group of diseases characterised by the uncontrolled growth and spread of abnormal cells. If this is not checked it can cause death. Nearly 80% of all cancer diagnoses are in people aged 55 or older. Some facts about cancer In 2015 around 1.7m new cancer cases were diagnosed in the US, and about 330,000 in the UK. Each year, there are some 589,430 cancer deaths in the US, and some 162,000 in the UK. The annual treatment cost of cancer for the US is about $90bn and for the UK about £10bn. The causes of cancer include genetic, and lifestyle factors; certain types of infections; and environmental exposures to different types of chemicals and radiation.  Whitfield Growdon, Oncology Surgeon at Massachusetts General Hospital and professor at the Harvard University Medical School describes cancer and the causes of cancer.


         

The Science paper: cancer is unavoidable

The Science paper found that 65% of cancer cases are a result of bad luck: random DNA mutations in tissue cells during the ordinary process of stem cell division; regardless of lifestyle and hereditary factors. The remaining 35% of cancer cases, say the authors, are caused by a combination of similar mutations and some environmental and hereditary factors. One implication of these findings is that preventative strategies will not make a significant difference to the incidence rates of most adult cancers. So accordingly, the optimal way to reduce adult cancers is early detection when they are still curable by surgery.
 
Stem cell division is the normal process of cell renewal, but the extent to which random cell mutations contribute to cancer incidence, compared with hereditary or environmental factors, is not altogether clear. This is what the John Hopkins researchers sought to address with their study. Scientists examined 31 tissue types to discover whether the sheer number of cell divisions increases the number of DNA mutations, and therefore make a given tissue more prone to become cancerous.
 
Researchers developed a mathematical model, which suggested that it is incorrect to assume that cancer may be prevented with “good genes” even though we smoke, drink heavily, and carry excess weight. Their study found that, "the majority [of adult cancer risk] is due to bad luck, that is, random mutations arising during DNA replication in normal, noncancerous stem cells."  And, "this is important not only for understanding the disease, but also for designing strategies to limit the mortality it causes," say the researchers.
 
According to the Science paper bad luck mutations account for 22 of 31 adult cancer types, including ovarian, pancreatic, bone and testicular cancers. The remaining nine, including lung, skin and colorectal cancers, occurred more often than the random mutation rate predicted. This suggests that in these cancers, either inherited genes or environmental factors have a significant influence on cases.
 
“Our study shows, in general, that a change in the number of stem cell divisions in a tissue type is highly correlated with a change in the incidence of cancer in that same tissue,” says Bert Vogelstein, Clayton Professor of Oncology at the John Hopkins University School of Medicine, and co-author of the study. One example, he says, is in colon tissue, which in humans, undergoes four times more stem cell divisions than small intestine tissue. Likewise, colon cancer is much more prevalent than small intestinal cancer.
 
In a BBC Radio 4 interview Cristian Tomasetti, co-author of the study said: “Let’s say my parents smoked all their lives, and they never got lung cancer. If I strongly believed cancer was only environment, or the genes that are inherited, then since my parents didn’t get cancer, I may think I must have good genes, and it would be OK to for me to smoke. On the contrary, our study says ‘no’, my parents were just extremely lucky, and played a very dangerous game.”

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The Nature paper: cancer is avoidable

In a BBC interview, Yusuf Hannun, Director of the Stony Brook Cancer Center, Joel Strum Kenny Professor of Cancer Research and one of the authors of the Nature paper, challenged the findings of the ‘bad luck’ study. He suggests that hiding behind ‘bad luck’ is like playing Russian roulette with one bullet; one in six will get cancer. "What a smoker does is add two or three more bullets to the revolver and pulls the trigger. Although there is still an element of luck, because not every smoker gets cancer, they have stacked the odds against themselves. From a public health point of view, we want to remove as many bullets as possible from the revolver," says Hannun.
 
The Nature paper rebuts the John Hopkins ‘bad luck’ thesis. Its lead author, Song Wu, from the Department of Applied Mathematics and Statistics at Stony Brook University, notes that the Science paper had not conducted an alternative analysis to determine the extent to which external risk factors contribute to cancer development, and it assumes that the two variables: intrinsic stem-cell division rates, and extrinsic factors, are independent. “But what if environmental factors affect stem-cell division rates, as radiation is known to do?” asks Wu.
 
Wu and his colleagues provide an alternative analysis by applying four analytical approaches to the data that were used in the earlier Science paper and arrive at a radically different conclusion: that 70 to 90% of adult cancer cases result from environmental and lifestyle factors, such as smoking, drinking alcohol, sun exposure and air pollution. Wu admits that some rare cancers can result from genetic mutations, but suggest that incidence rates of cancers are far too high to be explained primarily by mutations in cell division.
 
According to the Nature paper, if intrinsic risk factors did play a key role in cancer development, the total number of divisions in tissue stem cells would correlate with lifetime cancer risk, and the incidence rates of the disease would be less than it actually is. Wu and his colleagues analyzed the same 31 cancer types as in the earlier Science paper, and evaluated the number of stem cell divisions in each. They then compared these rates with lifetime cancer incidence among the same cancer types. This allowed them to calculate the contribution of stem cell division to cancer risk.
 
Wu et al also pursued epidemiological evidence to further access the contribution of environmental factors to cancer risk. They analyzed previous cancer studies, which show how immigrants moving from regions of low cancer incidence to regions with high cancer incidence soon develop the same tumor rates, suggesting that the risks are environmental rather than biological or genetic.
 
The researchers’ findings suggest that mutations during cell division rarely accumulate to the point of producing cancer, even in tissues with relatively high rates of cell division. In almost all cases, the Nature paper found that some exposure to carcinogens or other environmental factors would be needed to trigger disease, which again suggested that the risks of the most prevalent adult cancers are due to environmental factors. For example, 75% of the risk of colorectal cancer is due to diet, 86% per cent of the risk of skin cancer is due to sun exposure, and 75% of the risk of developing head and neck cancers is due to tobacco and alcohol.
 
The Nature paper concludes that bad luck, or intrinsic factors, only explain 10 to 30% of cancer cases, while 70 to 90% of adult cancer cases result from environmental and lifestyle factors. "Irrespective of whether a subpopulation or all dividing cells contribute to cancer, these results indicate that intrinsic factors do not play a major causal role," say the authors. This suggests that many adult cancers may be more preventable than previously thought. 
 

Preventing cancer 

Even the Science study concedes that extrinsic factors play a role in 35% of the most common adult cancers, including lung, skin and colorectal cancers. This, together with the Nature study, and the rising incidence of avoidable cancers, should be a wake-up call because a substantial proportion of cancers can be prevented.
 
Hannun is right! Whatever the causes of cancer, we should not ‘hide behind bad luck’.  We should act on evidence, which suggests that it is within everyone’s capabilities to make simple lifestyle changes that can prevent common adult cancers.  Although maintaining a healthy lifestyle is no guarantee of not getting cancer, the Nature paper underlines the fact that a healthy lifestyle stacks the odds in your favor.  The paper supports preventative cancer strategies.
 
In 2015, tobacco smoking caused about 171,000 of the estimated 589,430 cancer deaths in the US. The Nature paper suggests that the overwhelming majority of these could have been prevented. In addition, the World Cancer Research Fund has estimated that up to 33% of the cancer cases that occur in developed countries are related to being overweight or to obesity, physical inactivity, and/or poor nutrition, and thus could also be prevented.
 
It seems reasonable to suggest that the risk of cancer can be significantly reduced by: (i) a cessation of smoking, (ii) drinking less alcohol, (iii) protecting your skin from the sun, (iv) eating healthily, (v) maintaining a healthy weight, and (vi) exercising regularly.
 

The UK Position

Everyone understands the enormity of the burden of cancer, and what to do to reduce its risk. In the UK, as in other wealthy countries, there is no lack of money, no lack of resources, and no lack of expertise for cancer care. The annual spend on cancer diagnosis and treatment alone in the UK is about £10 billion. The UK also has a government appointed Cancer Czar charged with producing a national cancer plan to bring Britain's cancer survival rates up to those of European levels. Despite our understanding and all these resources, a 2014 study published in the Lancet suggests that cancer survival rates in the UK still lag more than 20 years behind many other European countries, and that people are dying needlessly.  Why is this?
 

Fear of preventative medicine 

Writing in The Times in January 2016, Sir Liam Donaldson, a former UK Chief Medical Officer, suggested that although preventative healthcare strategies are vital “to provide safe, high quality care without running out of money”, governments avoid helping the public to mitigate the risks of modern living, which can cause cancer, because of  “two primal political forces: the mortal dread of being labeled a ‘nanny state’, and a fear of removing people’s perceived pleasures.”
 
During Donaldson’s tenure between 1998 and 2010, the government rejected his recommendation for a minimum unit price for alcohol, and for the same reasons in 2014, the government rejected a tax on sugar recommended by Public Health England. Excess sugar increases the risk of cancer, heart disease and diabetes. According to Donaldson, without effective government action to lower the vast and escalating burden of cancer, and other chronic diseases, the NHS is unsustainable.
 
The missing link in preventative strategies is behavioral techniques that engage people who are at risk and help them change their behaviors. Such techniques have been demonstrated to be successful in both the UK and US. They explain how people behave, and encourage them to reduce unhelpful influences on their health, and change the way they think and act about important health-related issues such as diets, lifestyles, screenings and medication-management. See: Behavioral Science provides the key to reducing diabetes
 

Takeaway 

It is crucial that the UK government now embraces behavioral techniques to curb the curse of cancer.  Donaldson is right: if cancer, and other chronic diseases, which together consume the overwhelming percentage of healthcare expenditure, are not prevented the NHS will become unsustainable.

• Detecting pancreatic cancer early is a significant advance
• 80% of people with pancreatic cancer are diagnosed late
• Only 3% of pancreatic cancer patients survive 5 years after diagnosis
• 12% of pancreatic cancer is associated with obesity
• MD Anderson blood test is 100% accurate at detecting pancreatic cancer
• Urine test 90% accurate at detecting pancreatic cancer
• Both tests could be in the clinic in a few years

Liquid biopsies are poised to detect pancreatic cancer early, which is a significant advance.

This is important because the clinical symptoms arise late in people with this cancer. Eighty per cent of people with the disease are diagnosed when it has already spread, so they are not eligible for surgery to remove the tumour, which currently is the only potential cure. Only about 3% of patients diagnosed with pancreatic cancer survive five years after diagnosis.
 

The pancreas is an organ that sits close behind the stomach, and has two main functions: (i) producing digestive enzymes, which break down food so that it can be absorbed, and (ii) producing insulin, which regulates blood sugar levels. Pancreatic cancer occurs when cells are produced in the pancreas in an uncontrolled fashion. This can lead to a number of health risks. Almost half of all new cases of cancer of the pancreas are diagnosed in people aged 75 and over, and is uncommon in people under 40. This year, an estimated 48,960 adults in the US and some 9,000 in the UK will be diagnosed with pancreatic cancer. It is estimated that 40,560 US deaths, and about 9,000 deaths in the UK from this disease also will occur this year. Those at higher risk include people with a family history of the cancer, heavy smokers, and obese people. There is some suggestion that pancreatic cancer is a risk for people over 50 who are newly diagnosed with diabetes.
 

Pancreatic cancer and diabetes

Type-2 diabetes is considered to be associated with pancreatic cancer, but it is not altogether clear whether diabetes is a risk factor or a symptom. Two studies published in 2011; one in the British Journal of Cancer, and the other in the Annals of Oncology confirm the hypothesis that, “increased BMI and abdominal obesity are associated with increased pancreatic cancer risk.” One of the studies estimates that about 12% of all pancreatic cancers in the UK are attributable to overweight and obesity. Fatty tissue in overweight people produces more hormones and growth factors than those in people of a healthy weight. High levels of some of these hormones, including insulin, which is produced in the pancreas, can increase the risk of pancreatic cancer.

Dr Roni Sharvanu Saha, a consultant in acute medicine, diabetes and endocrinology at St George's Hospital, London, opines on the possible relationship between diabetes treatment and pancreatic cancer, and says that, “the jury is out” about the link. 


            
                

Blood test for pancreatic cancer 

Pancreatic cancer is devastating, it usually shows no signs or symptoms, and presents late. Being able to detect the disease early is considered life enhancing for patients. Scientists from the University of Texas MD Anderson Cancer Center believe they are close to developing a blood test to detect pancreatic cancer, which they describe as "a major advance". Early results, published in 2015 in the journal Nature, showed the test was 100% accurate. Experts said the findings were striking and ingenious, but required refinement before they could be used in the clinic.
 

Major advance

A wall of fat marks the boundary of every cell in the human body. The MD Anderson test hunts for tiny spheres of fat, called exosomes, which are shed by the cancers. Scientists looked for unique signatures of cancer in these fatty exosomes, and noticed that a protein called proteoglycan glypican-1 was found in much higher levels in people with pancreatic cancer. Further blood tests on 270 people showed it was 100% accurate at distinguishing between cancers, other pancreatic disorders and healthy tissue.

The need for such a test is huge. According to Dr Raghu Kalluri, one of the MD Anderson researchers, the test is, "not too far" from the clinic. "We think the ability to identify and isolate cancer exosomes is a major advance and provides the possibility of immensely benefiting our patients," says Kalluri.
 

Urine test for pancreatic cancer

Scientists from Barts Cancer Institute, Queen Mary College, London, have developed a simple urine test to detect pancreatic cancer. The UK-Spanish study, published in Clinical Cancer Research in 2015, showed that out of 1,500 proteins found in the urine samples of 500 people, three were seen to be at much higher levels in the pancreatic cancer patients. This provided a "protein signature" that could identify the most common form of the disease, and distinguish between this cancer and the inflammatory condition chronic pancreatitis, which can be hard to tell apart. The signature was found to be 90% accurate. More research is now planned, and scientists will focus particularly on people whose genes put them at particular risk of pancreatic cancer.
 

Advantages of urine over blood 

Lead researcher, Dr Tatjana Crnogorac-Jurcevic, said: "We've always been keen to develop a diagnostic test in urine as it has several advantages over using blood. It's an inert and far less complex fluid than blood, and can be repeatedly and non-invasively tested.  We're hopeful that a simple, inexpensive test can be developed, and be in clinical use within the next few years."

"For a cancer with no early stage symptoms, it's a huge challenge to diagnose pancreatic cancer sooner, but if we can, then we can make a big difference to survival rates," says co-author and Director of Barts Cancer Institute, Professor Nick Lemoine.
 

Takeaways

Although there is a significant amount of work still to do before these tests appear in clinics, the levels of accuracy reported by the researchers are striking, and suggest that, in principle, a liquid biopsy has been found for this devastating cancer, which is good news for patients suspected of having the disease.

• The scientific framework for understanding cancer has gone full circle
• Cancer research is back where it began 60 years ago
• Cancer mutations outsmart the smartest scientists
• Challenges for cancer treatment go beyond biological complexity 

After sixty years of cancer research we’re back where we started. That’s according to MIT cancer scientist Professor Robert Weinberg, known for his discoveries of the first human oncogene (a gene that causes normal cells to form tumors), and the first tumor suppressor gene.

Writing in the journal Cell in 2014, Weinberg argues that, in the 1950s scientists viewed cancer as, “An extremely complicated process that needed to be described in thousands of different ways.” Then, scientists believed viruses caused cancer, which was proved wrong. In the 1980s cancer scientists developed the notion that the disease was caused by mutant genes. “This gave . . . the illusion . . . that we would be able to understand the laws of cancer formation the way we understand, with some simplicity, the laws of physics," says Weinberg. This was not the case. Over the past decade, scientists have returned to where they started in the 1950s, and view cancer as an extremely complex disease, “We are once again caught in this quandary: how can we understand this complexity in terms of a small number of underlying basic principles?", asks Weinberg.
 

Each cancer is unique

Victor Velculescu, Professor of Oncology at Johns Hopkins University, and internationally known for his discoveries in cancer genomics, stresses the uniqueness of cancer. “Between everybody that has cancer today, to everybody that's probably ever had cancer since the beginning of humankind, [each person] has had different molecular alterations in this disease,” he says. Adding to cancers complexity is the fact that the disease mutates over time, which means that people become resistant to specific drugs, and clinicians are obliged to search for other treatments. Professor Axel Walther, Consultant Medical Oncologists and Director for Research in Oncology at University Hospitals, Bristol describes the challenges of drug resistance for cancer patients:

     
 

Pathways

A significant advance in cancer treatment is the notion that random “errors” in our genes, which cause cancer could be simplified into specific pathways, which are the “rail tracks” within cells along which chemicals flow that keep cells alive and functioning. Genes are “stations” along these pathways. There are thousands of pathways, some known and others, unknown, and their breakdown causes cancer. Discovering these pathways provides an opportunity to block the progress of cancer, with appropriate drugs.

Professor William Nelson, a recognized leader in cancer research, and Director of the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins, says, the complexity of cancer means that, “Only rarely can a single drug block a single pathway.” Most cancers require a combination of drugs. Walther describes the challenges that the complexity of cancer pose for personalised medicine:

   
 

Cost factor

Challenges in cancer treatment go far beyond biological complexity. Increasingly, the cost of drugs is an important factor. Dr. Richard Pazdur, the FDA’s Cancer Czar, questions how much longer the FDA can remain blind to drug prices, and the growing debate over how to place an appropriate value on cancer drugs, which can cost US$100,000 or more a year. Earlier this year NHS England withdrew funding for 25 cancer drugs because the costs were too high.
 

Takeaways

Weinberg is not defeated by the notion that the scientific framework for understanding cancer has come full circle. Over the past 60 years of cancer research, many ideas have flowed from laboratories, and led to incremental advances in treating cancer, and this will continue.

• Experts describe new prostate cancer study as the disease’s ‘Rosetta Stone’

• Prostate cancer kills nearly 11,000 men each year in the UK alone

• Men with untreatable prostate cancer could benefit from standard drugs

• Study opens black box of genetics to treat previously untreatable cancer

• Mediterranean diet lowers mortality risk for men with prostate cancer

A new UK-US cancer study could transform prostate cancer treatment, and give hope to sufferers whose cancers have become resistant to treatment. Experts’ hail the study as “incredibly exciting and ground breaking”. According to Professor Johann de Bono, of the Institute of Cancer Research, London, who led the British team, the study opens up a new era of treatment, in which men will be given drugs tailored to their tumours. 

Cancer is lethal when it metastasises and becomes resistant to drugs. The study, published in the journal Cell in 2015, involved 150 men close to death whose prostate cancers had spread throughout their bodies, and were not responding to available drugs. 
     

Prostate cancer’s ‘Rosetta Stone’

The research has opened up a black box in cancer genetics, and changes the way we think about and treat prostate cancer. Now that doctors have a map of which mutations to look for, they could search for them using a £200 test. 

De Bono, extracted samples of the cancer from metastatic tumors, and analysed their DNA, which showed that 90% of the men carried genetic mutations in their tumors, which matched drugs already on the market. A third of the men studied had tumors suitable for treatment with new drugs called PARP inhibitors.

‘’We're describing this study as prostate cancer's Rosetta Stone because of the ability it gives us to decode the complexity of the disease, and to translate the results into personalised treatment plans for patients. What's hugely encouraging is that many of the key mutations we have identified are ones targeted by existing cancer drugs - meaning that we could be entering a new era of personalised cancer treatment," says de Bono.

According to de Bono, “We are changing how long these men are living. This gives me hope that I can make a difference for men dying of prostate cancer. There is still a lot of work to do. This is not a cure, but it is a huge step forward.” 
 

Prostate cancer

In an earlier Commentary we discussed the dilemmas men face when they have been diagnosed with prostate cancer. Prostate cancer is the most common cancer in men, and each day in the UK alone 110 men are diagnosed with the disease. Cancer begins to grow in the prostate, a gland in the male reproductive system, and develops slowly. Although it can be cured if diagnosed early, there may be no signs that you have it for many years, and symptoms often only become apparent when your prostate is large enough to affect the urethra. Here cancer expert Professor Karol Sikora describes the symptoms of advanced prostate cancer:

         
             
Once prostate cancer begins to spread it becomes difficult to treat, and each year nearly 11,000 men die of the disease in the UK. Treatment options include watchful waiting, surgery, radiation, hormone therapy, chemotherapy, biological therapy and bisphosphonate therapy.
 

Mediterranean diet

According to research published in the journal Cancer Prevention Research, a Mediterranean diet rather than a Western diet may improve survivorship for men diagnosed with prostate cancer.

This is welcome news because there is a dearth of evidence to counsel men living with prostate cancer on how they can modify their lifestyle to lower the risk of mortality. The new study from Harvard’s Chan School of Public Health, investigated the diets of 926 men with prostate cancer for an average of 14 years after their diagnosis, and in 2015 published their findings, which suggest that people living with prostate cancer who ate a predominantly Western diet, high in red and processed meat, fatty dairy foods, and refined grains, were two-and-a-half times more likely to die from prostate cancer, and had a 67% increased risk of all-cause mortality, compared with participants who followed a Mediterranean diet, rich in vegetables, fruits, fish, whole grains, and healthy oils. In comparison, men who follow a Mediterranean diet had a 36% lower risk of all-cause mortality.

Lead author Meng Yang suggests treating the findings cautiously, "Given the scarcity of literature on the relationship between post-diagnostic diet and prostate cancer progression, and the small number of disease-specific deaths in the current study.”
 

Dietary supplements and vitamins

Researchers continue to look for foods (or substances in them) that can help lower prostate cancer risk. Scientists have found some substances in tomatoes (lycopenes) and soybeans (isoflavones) that might help prevent prostate cancer. Studies are now looking at the possible effects of these compounds more closely. Scientists are also trying to develop related compounds that are even more potent, and might be used as dietary supplements. 
 

Takeaways

Some studies suggest that certain vitamin and mineral supplements (such as vitamin E and selenium) might lower prostate cancer risk. But a large study of this issue, called the Selenium and Vitamin E Cancer Prevention Trial (SELECT), found that neither vitamin E nor selenium supplements lowered prostate cancer risk after daily use for about five years. In fact, men taking the vitamin E supplements were later found to have a slightly higher risk of prostate cancer.

De Bono’s breakthrough in cancer genetics means that many men whose prostate cancer was thought untreatable could be given drugs that are already on hospital shelves. Some patients have already benefited, and are alive more than a year on, despite only having been given weeks to live.