Can a tumour biopsy enable cancer cells to spread?

For most biopsies there are no risks in having the procedures performed and there are no associations between biopsies and the spread of cancer. However, for some specific and rare cancers it is felt better not to do the biopsy at the time, but to wait and carry out a definitive surgery. Either way, a tissue diagnosis has to be made whether that is by biopsy or by surgery.