The issue with cancer is that it has the ability to metastasize - that is to travel to other parts of the body and grow there. Thus even if we completely remove that tumor that we see initially, but there could still be millions or billions of cancer cells that are now in other parts of the body but have not grown into tumors that are big enough to see yet. Also, in your scenario, depending on the type of cancer - you can actually spread cancer cells along the path of the needles when you remove them.

In addition, some areas of the body make such surgery tricky because the cancer cells are very close and intertwined with critical structures. This can be especially true in brain cancers.

But there are techniques like you suggest that are used in cancer. http://www.nature.com/nrc/journal/v14/n3/full/nrc3672.html

Thanks for taking the time to make a suggestion. Like many areas, one of the ways breakthroughs in medicine occur is that someone with a fresh perspective suggests something that the experts are too close to see. I hope that this will someday happen with cancer.