Chemotherapy and the Immune Response
Chemotherapy is a long known treatment for cancer. With immunotherapy now coming in a playing a larger role in cancer treatment, hopefully the need for chemotherapy will diminish. However there are still situations where chemotherapy is useful or can be used synergistically with immunotherapy. Chemotherapy typically damages the cell and DNA and can sensitize the response to immunotherapy. It can also slow the growth of the cancer, making it an easier opponent for the immune system. Certainly the balance is to not have too much chemotherapy to become immune suppressive. Chemotherapy injected into tumors can have a benefit of tumor killing and enhance the immunotherapy response, while reducing side effects. With new combinations of immunotherapy, we may soon see the need for chemotherapy fade, but it certainly still has a supportive role in some cases.
Reference: L Bracci, G Schiavoni, A Sistigu, F Belardelli , 2013 Jun 21, Immune-based mechanisms of cytotoxic chemotherapy: implications for the design of novel and rationale-based combined treatments against cancer , https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3857622/