This Cancer Treatment Has a 100 Percent Success Rate, Study Says

It could be a game changer for people with one particular type of cancer.

When it comes to cancer drugs, the vast majority of candidates fail during clinical trials. In fact, according to the American Council on Science and Health, just 3.4 percent of oncology trials result in approval by the U.S. Food and Drug Administration (FDA) or another regulatory body. That's just part of what makes the staggering success of one recent cancer drug trial so impressive.

After testing an immunotherapy treatment in a small group of individuals with stage 2 and stage 3 rectal cancer, researchers found that every single subject entered remission. Read on to learn about the trial experts are calling "unprecedented" and "paradigm-shifting," and to find out who may benefit from these groundbreaking advancements.

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Colorectal cancer is among the most common types of cancer.

Doctor using digital tablet and talking to patient at home

Colorectal cancer is the third most common kind of cancer in the United States. Nearly 45,000 new cases of rectal cancer and over 106,000 colon cancer cases are diagnosed each year, says the American Cancer Society.

While the overall number of rectal cancer cases have fallen since 2013 thanks to enhanced screening and changes in lifestyle risk factors in older patients, cases are rising at a rate of two percent each year among adults under 50. The most common treatment for all stages of rectal cancer is surgery, though many patients also undergo radiation and chemotherapy.

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A new treatment has a 100 percent success rate in fighting some types of rectal cancer.

Woman hugging her doctor

In a small trial of 12 subjects with localized rectal cancer, researchers from Memorial Sloan Kettering Cancer Center (MSKCC) found that an experimental immunotherapy treatment caused all 12 individuals to go into remission. After receiving eight doses of the IV-administered treatment dostarlimab, each of the subjects' tumors were rendered undetectable by endoscopy, MRI, PET scans, or physical exam.

"These are immunotherapy medicines that work not by directly attacking the cancer itself, but actually getting a person's immune system to essentially do the work," Hanna Sanoff, MD, of the University of North Carolina's Lineberger Comprehensive Cancer Center told NPR's All Things Considered.

The study, published last week in The New England Journal of Medicine, explains that the "checkpoint inhibitor" treatment was given every three weeks for six months in patients with "mismatch repair–deficient" stage 2 and stage 3 localized cancer. Roughly five to 10 percent of all rectal cancer patients would be considered good candidates for this particular treatment, Sanoff noted.

Though the test group was small in size, the treatment's 100 percent success rate astonished even the researchers themselves. "I believe this is the first time this has happened in the history of cancer," Luis A. Diaz Jr., MD, an author of the study, told The New York Times.

The treatment revealed no significant side effects during the trial.

Closeup shot of female doctor writing prescription

Historically, the five-year survival rate for localized cases of rectal cancer has been 90 percent, says the American Society of Clinical Oncology (ASCO). If the cancer has spread to other tissues, organs, or lymph nodes, the survival rate is 73 percent.

However, many of those surviving patients who undergo surgery—the most common form of treatment for rectal cancer—go on to experience serious side effects.

"In rectal cancer, this is part of the conversation we have with someone when they're diagnosed. We are very hopeful for being able to cure you, but unfortunately, we know our treatments are going to leave you with consequences that may, in fact, be life-changing," Sanoff explained. "I have had patients who, after their rectal cancer, have barely left the house for years—and in a couple of cases, even decades – because of the consequences of incontinence and the shame that's associated with this," added Sanoff, who did not work on the study but wrote an editorial accompanying it.

This study is just the beginning, researchers say.

A Korean senior woman with cancer is wearing a scarf on her head. She is standing and holding a cup of tea. The woman leans against a window and smiles with gratitude and hope.

Given the small size of the trial, more research is needed to confirm the team's results and further explore possible side effects. In the broader population of patients that take checkpoint inhibitors, three to five percent have more serious complications such as muscle weakness and difficulty chewing or swallowing, reports The New York Times.

Experts also expect that the 100 percent success rate will drop as the treatment is tested on a larger subject pool.

Still, the results are both extraordinary and encouraging for the patients who suffer from rectal cancer and the doctors who treat them. "I am incredibly optimistic," said Sanoff of the study, calling the findings "paradigm-shifting."

"We have never seen anything work in 100 percent of people in cancer medicine," she added.

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Lauren Gray
Lauren Gray is a New York-based writer, editor, and consultant. Read more
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