When the Morine Sideris was told that he had cancer in 2022, a tumor at his esophagus and stomach junction, his first fear was not death. It was losing his voice.

“I was afraid that if I received surgery on my esophagus, I would not be able to talk for some time,” he remembered. “It would have been terrible.”

But instead of going under the knife or through punished cycles of chemotherapy, Mine was nominated in a clinical trial at the Memorial Slone Catering Cancer Center (MSK) in New York.

Treating his? Just six months immunotherapy, no surgery, no radiation, no chemo.

Today, he is cancer-free.

Morin is one of 84 patients, whose tumor had completely disappeared after receiving an immunotherapy drug, dostarlimab in a step 2 clinical trial.

The American Association for Cancer Research (AACR) shared at the 2025 annual meeting and the results published in the New England Journal of Medicine, some can mark a paradigm change with cancer.

Gastrointestinal oncologist Dr. in MSK. Andrea Sarek and Dr. The test led by Luis Diaz Junior nominated 103 people with locally advanced cancer, including rectal, colon, esophagal, liver, urinary and anti -breast tumors.

Something was common in all: a genetic signature called MMRD, lack of mismatch repair.

This mutation makes tumors more prone to DNA mimicing errors, but also appear more for the body’s immune system, making them ideal targets for checkpoint inhibitors such as dostarlimab, which are sold under the brand name jambarli.

Czechpoint inhibitors work by taking brakes from the immune system, allowing it to spot and destroy cancer cells that usually hide in plain vision.

The most striking results came from 49 patients of rectal cancer, each one had a complete reaction, meaning that their tumors disappeared. Among other 54 patients with cancer in various organs, 35 also experienced total discounts.

Severe, 82 of the 84 patients who went to the remuneration were able to avoid entire surgery.

“This study suggests that immunotherapy may replace surgery, radiation and chemotherapy for solid tumors with mismatched repair-least, which can help patients preserve their organs and avoid the harsh effects of chemo and radiation,” Dr. Sarek said.

For years, standard treatment for multiple solid tumors, especially in digestive and reproductive systems, has been a rigid tride: surgery, chemotherapy and radiation.

Often being effective, these approaches come with heavy side effects: pain, fatigue, infertility, incontinence, loss of sexual function and long recovery period.

What this new test shows shows that for patients with MMRD cancer, there may be another method.

To monitor how well the treatment was doing, researchers used an emerging device, called CTDNA test, which is small to transmit tumor DNA.

It is a type of liquid biopsy, a blood test that detects small pieces of tumor DNA in the bloodstream.

Using a technique called Hastac MRD developed by Quest Diagnostics, they were able to find out if the tumor had disappeared in 1.4 months.

This can make future cancer monitoring not only rapid but also safe and more accessible.

Out of 103, 49 had rectal cancer. Each of them had a complete response of (100%), which meant that their tumor disappeared after immunotherapy.

The remaining 54 patients had other types of cancer (such as colon, liver, esophagus, etc.). Of these, 35 noticed that their cancer had disappeared – 65% success rate.

Overall, 84 out of 103 patients had complete reaction to treatment. Among the 84 patients who had a complete reaction, 82 did not require surgery, a big thing, because traditional cancer treatment often involves removal of organs or tissue.

Most patients with specific cancer mutation (MMRD) responded incredibly well to immunotherapy alone, in which there is no need for chemo, radiation, or surgery, especially with rectal cancer.

It is important to note that not all cancer patients will benefit from this treatment.

But for those who have this genetic mutation, the test provides a completely new way.

The results suggest that in the future, blood test ctdna can become an important tool to check how to cancer treatments are working, especially when the tumor is in a part of the body, which is difficult to reach or can be easily seen or cannot be tested with biopsy.

Dr. Sarek and Dr. For Diaz, the goal now is to expand this approach to even more types of cancer.