Rewriting cancer treatment: Breakthrough US trial cures without chemo or surgery

In a groundbreaking clinical trial that could redefine cancer treatment, researchers at the Memorial Sloan Kettering Cancer Center in the United States have successfully treated rectal cancer patients without the need for surgery, chemotherapy, or radiation. Instead, patients received a novel immunotherapy drug — dostarlimab — and emerged cancer-free, with minimal side effects and preserved fertility.

The Phase II trial, which enrolled 117 patients with various mismatch repair-deficient (dMMR) cancers, delivered extraordinary results: every single rectal cancer patient responded to the drug, and none required additional treatments. For these patients, the recurrence-free survival rate at two years stood at an unprecedented 96%.

A life-altering alternative

Traditional rectal cancer treatments often leave patients with irreversible complications—ranging from incontinence to infertility due to aggressive surgeries and chemoradiation. But dostarlimab, an immunotherapy drug that targets the PD-1 protein (which inhibits immune T-cells), offers a targeted, less invasive path forward.

“This changes everything,” one researcher noted. “We’re talking about eliminating cancer without cutting, burning, or poisoning the patient.”

Among the trial’s 117 participants, 49 had rectal cancer, while the remaining 54 had other solid tumors, including colon, esophageal, gastric, and prostate cancers. Of the latter group, 35 became completely cancer-free, with only two requiring surgery—and even those showed tumor shrinkage or downgrading.

How it works

Dostarlimab belongs to a class of drugs known as immune checkpoint inhibitors. It disables the PD-1 protein, effectively "releasing the brakes" on immune T-cells, allowing them to attack cancer cells more effectively. The treatment is specifically effective for cancers with dMMR mutations, found in roughly 10% of rectal and solid tumor cancers.

Mismatch repair deficiency impairs the body's ability to fix DNA replication errors, making cells more prone to mutations and, ultimately, cancer. Targeting these vulnerabilities with immunotherapy has shown that some cancers can be cured without conventional toxic treatments.

A personalized, less devastating regimen

Unlike one-size-fits-all cancer treatments, dostarlimab offers a personalized approach with the potential for fewer complications. Importantly, three participants were able to conceive and give birth after treatment — a result nearly unimaginable with conventional therapies.

"This is the first time in history we've seen such a complete response with immunotherapy alone in rectal cancer," said one of the lead oncologists.

The cost of hope

While the findings signal a new era in oncology, access remains a concern. Dostarlimab is already approved and available in India, but its use is currently limited by cost. Each dose is priced around $11,000, putting it out of reach for many patients unless costs come down or insurance coverage expands.

What’s next?

Experts caution that larger, longer-term studies are needed to confirm these early results. However, the success of dostarlimab could reshape how doctors approach not only rectal cancer but a broader range of solid tumors with similar genetic profiles.

For now, the dream of curing cancer without chemo, radiation, or surgery is closer than ever before — not just a hope, but a documented reality for dozens of patients.