Yes, cancer can come back in the same place. This is called local recurrence. In spite of a doctor’s best efforts, treatments like surgery may leave some microscopic cells in the primary site or chemotherapy sometimes fails to get rid of all the cancer cells that have spread. It may seem like a tumour has been removed or shrunk away, but a small number of remaining cells could regrow the tumour after time. Sometimes the cancer causing agent has caused changes across a field of cells (for example the inner wall of the bladder) and cancers may grow at different times across that whole area. It’s a bit like removing a tree. You get rid of most of it, but seeds may still be in the ground, and it is possible they can regrow over time. The challenge facing surgeons, doctors and cancer researchers is to find ways of getting rid of all the cells in a tumour so that it has far less chance of recurring.