For decades, the gold-standard treatment for many cancers has been a combination of surgery, radiation, and chemotherapy. However, recent research has shown that immunotherapy is a potential new and better approach to cancer therapy.
While these approaches, as mentioned earlier, can save lives, they often leave lasting side effects: pain, bowel or bladder problems, infertility, and fatigue, to name a few.
Recent clinical research offers a glimpse of a different future: for a carefully selected group of patients, immunotherapy might make invasive surgery and toxic chemotherapy unnecessary.
Table of Contents
Landmark Study Shows Complete Responses to Immunotherapy
In 2022, researchers at Memorial Sloan Kettering Cancer Center (MSK) in New York published a small but remarkable phase-2 trial in The New England Journal of Medicine (NEJM).
Twelve patients with locally advanced, mismatch repair-deficient (dMMR) rectal cancer received the PD-1 inhibitor, dostarlimab, as their initial treatment.
After six months of therapy and rigorous imaging, endoscopy and physical examinations, every participant achieved a complete clinical response. None required the standard path of chemoradiation followed by major rectal surgery.
Two years on, follow-up reports indicate that these responses remain durable, with no evidence of cancer recurrence in the original cohort.
This result is striking; not a single patient needed chemotherapy, radiation or surgery – treatments that typically carry high risk of lifelong bowel or sexual dysfunction and, for some, a permanent colostomy bag.
How PD-1 Immunotherapy Works
Immunotherapy harnesses the body’s own immune system to recognise and destroy cancer cells. PD-1 inhibitors such as dostarlimab and pembrolizumab block a “checkpoint” protein on immune T-cells.
Many cancers exploit PD-1 to hide from immune attack. By disabling this checkpoint, PD-1 inhibitors unleash T-cells to hunt down tumour cells.
This approach works especially well in tumours with mismatch repair deficiency or high microsatellite instability (MSI-H).
These cancers accumulate large numbers of DNA mutations, creating abnormal proteins that are easier for the immune system to detect once it is activated.
Why Organ Preservation – A Benefit of Immunotherapy Matters
For locally advanced rectal cancer, the traditional route: chemoradiation followed by surgery, can be life-altering.
Surgical removal of part of the rectum often leads to permanent changes in bowel habits, urinary or sexual dysfunction, and sometimes there is need for a colostomy.
If immune checkpoint inhibitors can safely produce lasting remission, patients could preserve their organs and maintain a better quality of life.
This is more than a convenience; it is about dignity, long-term health, and reducing the physical and financial toll of cancer care.
Broader Evidence of Immunotherapy’s Power
The MSK trial is not an isolated finding, as other studies reinforce the potential of PD-1 inhibitors, as observed.
For example:
- 1. KEYNOTE-177 trial: In patients with MSI-H or dMMR metastatic colorectal cancer, pembrolizumab significantly improved progression-free survival compared to standard chemotherapy.
2. CheckMate-816 trial: For certain non-small-cell lung cancers, combining nivolumab (another PD-1 blocker) with chemotherapy before surgery improved the rate of complete pathological response.
These data suggest that, at least for cancers defined by specific biomarkers, immunotherapy can outperform or complement chemotherapy and may even reduce the need for surgery.
Immunotherapy -Not a Universal Cure
Despite the excitement, it is important to emphasise that we cannot yet claim this novel approach as a universal cure. This is due to a combination of factors such as:
– Small sample size: The dostarlimab study included only 12 patients. Larger, multi-centre trials are underway to confirm both effectiveness and safety.
– Strict patient selection: Only tumours with dMMR or MSI-H mutations have shown such dramatic responses. Most colorectal and rectal cancers do not carry these markers.
– Need for meticulous follow-up: Skipping surgery is only safe when doctors can monitor patients closely with MRI, endoscopy and biopsies to ensure no hidden disease remains.
– Potential side-effects: Immune-related adverse events like colitis, liver inflammation, endocrine disorders can occur, sometimes requiring steroids or hospitalisation.
As oncologists often note, these results are practice-informing rather than practice-changing at a population level.
Implications for Patients in Nigeria and Beyond
For Nigerian patients, these breakthroughs highlight the importance of biomarker testing.
Determining whether a colorectal or rectal tumour is dMMR or MSI-H is now crucial for deciding treatment options.
Access to PD-1 inhibitors remains limited in many low and middle-income countries due to cost and regulatory hurdles. However, as generic versions emerge and global trials expand, more patients may benefit.
Healthcare policymakers and cancer advocacy groups can play a role by promoting genetic testing infrastructure and negotiating for affordable access to these life-saving drugs.
Key Takeaways
Immunotherapy with PD-1 inhibitors can induce complete responses in a subset of rectal cancers, allowing some patients to avoid surgery and chemotherapy.
The strongest evidence so far comes from the NEJM phase-2 dostarlimab trial at Memorial Sloan Kettering.
Broader studies like KEYNOTE-177 and CheckMate-816 show PD-1 blockade is effective in several other cancers, though usually as part of a combined strategy.
Adoption into routine care awaits larger confirmatory trials, longer follow-up and wider drug availability.
Final Thoughts
The era of one-size-fits-all cancer treatment is fading as immunotherapy, especially PD-1 inhibitors such as dostarlimab is transforming how clinicians approach rectal cancer and other mismatch repair-deficient tumours.
For carefully selected patients, this innovation could mean organ preservation and freedom from the harsh side-effects of chemotherapy and surgery.
While the journey from groundbreaking trial to everyday clinic is ongoing, these findings offer hope that future cancer care will be more precise, less invasive and more humane.
Read Also: Colon Cancer: Symptoms, Risk Factors & Treatment
