A Cure for Colorectal Cancer on the Horizon?
There might be a cure on the horizon for one of the most common cancers in Canada. Colorectal cancer occurs often among adults 50 years of age and older and usually develops from benign polyps called adenomas. Early warning signs of colorectal cancer include blood on or in your stool, sudden changes in bowel habits, abdominal pain, and fatigue. It affects both men and women at similar rates, being the second most common cancer after prostate in men and the second after breast cancer in women.1
If you are between 50-74 years of age, you will usually receive testing recommendations from your healthcare provider even if you have no symptoms. Individuals with inflammatory bowel disease (primarily Crohn’s disease and ulcerative colitis) affecting their colon for eight to ten years have a slightly higher risk of developing colorectal cancer so their screening recommendation might be more frequent, at every one to two years.
With screening and early detection, colorectal cancer can be preventable and easy to treat and there are a number of effective therapies and medicines available. For locally advanced colorectal cancer, physicians typically use a combination of chemotherapy, radiation, and surgery. These treatments can have significant impacts on quality of life as they can permanently affect such things as fertility as well as bladder and bowel function. About 5-10% of colorectal cancers are locally advanced mismatch repair-deficient (dMMR) and studies have shown that chemotherapy is not effective for this type of rectal cancer.2
Dostarlimab (Jemperli®),3 a monoclonal antibody that belongs to a class of medications known as programmed death 1 (PD-1) inhibitors, is a type of protein that recognizes and attaches to a specific target substance in the body and helps your immune system fight cancer. In an early-stage clinical trial from the Memorial Sloan Kettering Cancer Center in New York,1 all 12 individuals with dMMR rectal cancer that completed the trial received dostarlimab and experienced a clinical complete response. There was no evidence of tumor on magnetic resonance imaging, endoscopy, digital rectal exams, or biopsy during several intervals of follow up after treatment. This is a remarkable success; however, this study was very small and must be replicated in larger trials with patients from diverse backgrounds. These clinical trials are continuing until 2025 to assess the ongoing safety and effectiveness of dostarlimab for colorectal cancer.4 The scientists also hope that future research will look into the effectiveness of PD-1 inhibitors in other cancers with dMMR, such as pancreatic and gastric cancer.1
Currently, dostarlimab is available in Canada2 as a monotherapy infusion for the treatment of recurrent or advanced unresectable endometrial cancer (cancer of the lining of the uterus). It does not yet have an indication for colorectal cancer.
Biomarkers
Our bodies contain chemical signatures, called biomarkers, that can tell us valuable information about our health, such as predicting our risk for disease and finding the best therapies for an individual’s biology. Learn more by watching our video: