– Why is cancer treatment measured in 3 and 5 year survival rates?

Question

Is cancer so “uncurable” we only hope to extend the patient’s life and not cure it completely?

In: Biology

Answer 1

Since cancer comes from mutations that change the cell workings, and those errors are passed on through that cell lineage, unless you are able to kill every cell of that lineage, the cancer may come back.
And since those mutations can happen for many reasons, some hereditary and some environmental, you may have another cancer happening after the first was “cured” (all cancerous cells destroyed) because you already have conditions that facilitate those mutations.