It is interesting to think that we might be able to test a cancer cell in the lab, to determine which chemotherapy drugs might be able to kill it, and which cannot. I am referring to chemotherapy sensitivity tests that assess cancer cells directly in a lab, to see which chemotherapy drugs are more likely to cause cell death. Outside of clinical trials, there is some debate about their clinical utility among Medical Oncologists and use is variable.
There are some important points to keep in mind about these tests:
- Potentially curable (stage I to III) cancers. Such tests do not have a role in treatment of potentially curable (stage I to III) cancers and have not been included in standard consensus guidelines. For the most common cancers we encounter, such as those of lung, breast, colon, ovary, and uterus, painstaking research over decades has defined curative chemotherapy. Such chemotherapy used upfront, or as an “adjuvant” (see my article about this topic), can markedly increase cure rates. At this time, we do not have any research showing that chemotherapy sensitivity test results should make us give treatments other than what has been well studied.
- Often incurable (stage IV) cancers. This is the setting where such tests are more likely to be considered. Still, even in the setting of incurable cancer, there are extensively studied therapies that can shrink tumors, improve symptoms, and help prolong survival while preserving quality of life. The likelihood that an individual may benefit from such “palliative” treatments can be quite high, even in excess of 40% for initial treatment of some stage IV cancers. It is very common that such tried and tested treatments may be used initially, and chemotherapy sensitivity testing employed when options seem to be limited. However, in some settings, chemotherapy sensitivity testing may be used earlier on also.