New Immunotherapy Trial Offers Hope of Replacing Surgery and Chemotherapy for Certain Tumours

In a landmark development in cancer research, a recent clinical trial has demonstrated that immunotherapy alone can lead to complete tumour remission in many patients—without the need for surgery, radiation, or chemotherapy. The findings, which could reshape treatment standards for certain genetic forms of cancer, offer renewed hope for patients seeking less invasive and more targeted therapeutic options.

Clinical Trial Design & Key Findings

The trial, conducted by leading oncologists at Memorial Sloan Kettering Cancer Center, enrolled 103 patients with early-stage to locally advanced solid tumours across multiple organs, all of which shared a specific genetic marker called mismatch repair deficiency (MMRd). Tumours with this mutation tend to produce more DNA copying errors, making them more visible to the immune system and particularly responsive to immune‐based treatments.

Participants received the immunotherapy drug dostarlimab over approximately six months. The response was profound: 84 out of 103 patients achieved a complete response, meaning their tumours fully disappeared with no detectable disease. In particular, every patient with rectal cancer in the trial (49 individuals) showed complete remission. Among others with cancers of the colon, esophagus, liver, urinary tract, and gynecologic organs, 35 out of 54 also had their tumours disappear.

Implications for Cancer Treatment

• Organ Preservation: Many patients were able to avoid surgery altogether, which may reduce the risks of long‐term complications, disfigurement, and impact on quality of life.
• Reduced Toxicity: Without the need for chemo or radiation, patients may avoid many of the adverse effects commonly associated with those treatments.
• Personalized Medicine Confirmation: The success of this approach reinforces the importance of genetic profiling (e.g., identifying MMRd status) to determine which patients are likely to benefit.

Challenges & Next Steps

While the results are highly promising, experts caution that the findings are specific to MMRd tumours and may not apply to the majority of cancers without that genetic signature. More extensive trials, longer follow-up, and larger patient cohorts are needed to confirm durability of remissions and long-term safety.

Additionally, monitoring response through emerging tools such as circulating tumour DNA (ctDNA) in blood (“liquid biopsies”) was used in the trial to assess when tumours disappeared. These technologies will likely become critical in future treatment monitoring and tailoring therapy.

Why This Breakthrough Matters

This trial represents a potential paradigm shift: moving away from the “three-pillar” model of surgery, toxic systemic therapy, and radiation for some cancers, toward treatments that are less invasive and more aligned with tumour biology. If the positive responses are sustained over time, this could change standards of care and bring hope to patients for whom conventional therapies carry high risks or severe side effects.

Outlook

Researchers are already planning to expand the trial to more cancer types and diverse patient populations, to assess long-term outcomes and explore how immunotherapy alone may be incorporated into treatment protocols. Regulatory approvals, cost, access, and infrastructure will also be crucial considerations. But for now, this breakthrough points toward a future in which a subset of cancer patients may be able to avoid surgery and harsh treatments—while still achieving complete remission.