Dear Arshad,

Even an escaped cancer cell from any therapy could be enough for recurrence of the tumor. This one cancer cell is generally a cancer stem cell and that means this cell can create a new tumor. In most of the cases, cancer stem cells are very resistant to treatments. So, doctors know that and they can not give a 100% promises. If you want to know the details, I suggest you to read about cancer stem cells.

Good luck

There is "nothing" certain in medicine.

Dennis

Dennis Mazur

As there is always a chance of spreading of cancer cells to other area/ organ of the body where it can start multiplication and cause cancer.

This spread is called as Metastasis.

The main problem is resistance towards these therapy. Cancer cell have the ability to become mutant. For example cancer cells uses body's own mechanism such as P-GLYCOPROTEINS. These proteins throw the cancer medicine out of the cancer cells and does not allow them to work. So simply doctors can not promise 100% cure. Another reason is that an individual can respond variably. One treatment might be effective for him but not for another individual. Then there is always a chance that micrometastasis are present which can spread the disease to other organs. Ultimately time will tell the story of the individual. However patients can still survive upto 10 to 15 year even after metastasis.

Kindest regards

DR SABA TARIQ