Every March is Colon Cancer Awareness month. Colorectal cancer is the second most common cancer and affects over 130,000 Americans every year. Screening asymptomatic individuals at age 50 and those at high risk sooner can offer early detection and an opportunity to cure some patients. However, almost 50,000 Americans continue to die of advanced stages of this disease annually. Yet another disturbing trend is the growing incidence of colorectal cancers in younger patients in their 20s and 30s.
As a medical oncologist, I often see patients who present with advanced stages of colon cancer. Thankfully, there has been significant progress in treating patients with metastatic disease. There are several effective approved targeted therapies for patients with metastatic colon cancer. Genetic testing has helped to identify patients whose tumors may respond to these newer drugs. Patients with metastatic colon cancer that are mutated in the KRAS, NRAS, or BRAF genes are unlikely to respond to drugs targeting the EGFR pathway. These mutations should be routinely checked in metastatic patients to personalize chemotherapy options for an individual’s cancer.
We are learning that each individual’s colon cancer is different partly due to the location of the original tumor. Different genes appear to be expressed whether a tumor arises in the right or left side of the colon. Patients with right sided colon cancer are more likely to have Lynch Syndrome than those tumors that arose on the left side. Lynch Syndrome is a hereditary genetic condition which results in high levels of gene mutations within a tumor. These mutations may make the cancers more susceptible to immunotherapy drugs. Immunotherapy drugs have already made a significant impact in patients with melanoma, bladder, lung, and head and neck cancers. Several ongoing studies are investigating this in a subset of colon cancers. Our practice is also participating in one of the immunotherapy trials evaluating the use of pembrolizumab in patients with Lynch type metastatic colon cancer.
A significant amount of research has also gone into understanding cancer stem cells. Cancer stem cells play a role in the constant renewal of tumor cells and the development of chemo resistance in metastatic colorectal cancer. Cancer stems have abnormal cellular signaling pathways differentiating them non-malignant stem cells. Targeting these pathways in cancer stem cells is another promising way to control metastatic colon cancer. There is an ongoing phase 3 clinical trial combining a stem cell inhibitor drug with standard FOLFIRI chemotherapy. Our practice is participating in this exciting study and enrolling patients that qualify. Hopefully, these trials will add to our treatment options for colon cancer patients in the future.
Do not hesitate to contact me or my colleagues if we can be of help to you or a loved one.