Colorectal Cancer
Colorectal cancer is one of the most commonly diagnosed cancers globally and a leading cause of cancer-related deaths.
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Overview
Colorectal cancer begins in the colon or rectum, parts of our digestive system responsible for processing and eliminating waste. It typically develops from small, noncancerous growths called polyps, which can become cancerous over time if not detected and removed.
Risk factors include age, family history, inflammatory bowel diseases, lifestyle factors (such as diet, smoking, and alcohol use), and certain inherited syndromes. Most cases occur in people aged over 50, but recent data has shown an alarming increase in the number of younger people diagnosed with colorectal cancer. Regular screening can detect polyps before they turn into cancer, making early detection especially important.
While surgery, chemotherapy, and radiation have long been the cornerstones of treatment, immunology research is opening the door to new and promising treatment options, especially for patients with tumors that have specific genetic features.
Key Points
- Colorectal cancer is one of the most commonly diagnosed cancers globally and a leading cause of cancer-related deaths.
- Immunotherapy is effective for some patients, particularly those with tumors that have a specific genetic profile.
- Ongoing research is expanding the role of immunotherapy through combination treatments, vaccines, and cell-based approaches.
Key Statistics (U.S.)
Key Statistics
Global incidence: An estimated 1.9 million new cases and more than 930 000 death worldwide in 2022.
U.S. incidence: In 2025, about 107,320 new cases of colon cancer and 46,950 new cases of rectal cancer will be diagnosed. Colorectal cancer is expected to cause about 52,900 deaths during 2025.
Immunology and Colorectal Cancer
Studying colorectal cancer has helped researchers understand how genetic changes in tumors can influence how the immune system responds. This has helped to identify when immunotherapy is more likely to work.
A major discovery was the discovery of a specific genetic profile called ‘microsatellite instability-high/mismatch repair deficient’, or MSI-H/dMMR for short. Tumors with this profile (which make up around 15% of all colorectal cancers) accumulate large numbers of mutations, making them more visible to the immune system. As a result, they respond particularly well to checkpoint inhibitors, a type of immunotherapy that can help the immune response against cancer.
Checkpoint inhibitors such as pembrolizumab (Keytruda) and nivolumab (Opdivo) are now approved for advanced colorectal cancer with MSI-H/dMMR status, offering long-term disease control for some patients. In fact, pembrolizumab has become a first-line treatment option for these patients, replacing chemotherapy in some cases.
What’s next for colorectal cancer?
Other immunology-driven advances are under investigation, including:
- Cancer vaccines aimed at training the immune system to recognize colorectal cancer antigens
- Bispecific antibodies that help T cells directly bind and kill cancer cells
- Adoptive cell therapies, using engineered immune cells like CAR T cells, although these are still in early trials for colorectal cancer.
By identifying which tumors are likely to respond to immunotherapy, and designing treatments that enhance those responses, immunology is helping tailor more effective options for colorectal cancer patients.
Sources
- Colorectal Cancer Awareness Month, Cancer Research Institute
- Colorectal Cancer, World Health Organization
- Key Statistics for Colorectal Cancer, American Cancer Society
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