Breakthrough results in a recent phase II clinical trial offer patients with rectal cancer hope for a cure.
The small study was conducted at Memorial Sloan Kettering Cancer Center in New York City.
A dozen patients were given the checkpoint inhibitor dostarlimab (Jemperli) intravenously every three weeks for six months.
The clinical trial investigated “if immunotherapy alone could beat rectal cancer that had not spread to other tissues.”
Researchers report 100 percent of the patients experienced remission of rectal cancer.
“In every case, the rectal cancer disappeared after immunotherapy … and the cancer has not returned in any of the patients, who have been cancer-free for up to two years,” according to the center’s online post.
None of the patients underwent standard treatment options — radiation, surgery or chemotherapy.
Their tumors were closely tracked, “using imaging, visualization such as endoscopy, as well other methods,” said researcher Luis Alberto Diaz, MD.
The study participants had unique criteria. All patients in the trial were required to have stage two or stage three rectal tumors that contained a specific genetic mutation. This mutation is known as mismatch repair-deficient (MMRd) or microsatellite instability (MSI).
These criteria made their cancer particularly sensitive to immunotherapy, according to the center.
About 45,000 Americans are diagnosed each year with rectal cancer. Between 5 and 10 percent of all rectal cancer patients are thought to have MMRd tumors, according to the center.
Results of the trial were published in the New England Journal of Medicine in June.
Cancer Immunotherapy Effective in Study
“Our first duty is to save our patient’s life,” said researcher Andrea Cerek, MD, in the center’s report.
A second goal was to preserve patients’ quality of life. Rectal cancer patients who undergo surgery, radiation and chemotherapy can have severe side effects. They can suffer bowel and bladder dysfunction, incontinence, infertility and sexual dysfunction.
As an alternative cancer treatment, “immunotherapy harnesses the body’s own immune system as an ally against cancer,” according to the center.
Follow-up will be needed to determine if these results are long lasting.
“This approach, if the results are confirmed, holds out the hope of cure without the need for potentially toxic therapy and the need to tolerate long-term negative treatment consequences in order to achieve a cure,” said Dr. Diaz at the 2022 American Society of Clinical Oncology Annual Meeting.
The cancer center plans to continue the research study — ultimately enrolling 30 patients.
Hanna K. Sanoff, MD, MPH, at the University of North Carolina Lineberger Comprehensive Cancer Center, commented on the results: "These initial findings of the remarkable benefit with the use of dostarlimab are very encouraging but also need to be viewed with caution until the results can be replicated in a larger and more diverse population" (Medical Xpress).
Don’t Delay Colorectal Cancer Screening
In the United States, colorectal cancer (CRC) is the second-leading cause of cancer death.
The American Cancer Society (ACS) estimates more than 150,000 individuals will be diagnosed with colon and rectal cancer in 2022. More than 52,000 will die from the disease this year, according to the ACS.
CRC is one of the most preventable cancers through timely screenings. The disease often begins as a growth, called a polyp, inside the colon or rectum, according to the National Cancer Institute.
Many screening methods are available for CRC, but a colonoscopy is the gold standard. It is the only screening that can both detect and even prevent CRC. During a colonoscopy, a doctor can find and remove polyps in the colon (large intestine) or rectum before they become cancerous.
Leading health agencies now recommend screenings starting at age 45, not 50, for all individuals at average risk. People at high risk or a family history of CRC should be screened earlier.
Most health insurance plans cover colonoscopy as a preventive screening. Many plans now also cover colonoscopy as a follow-up screening to evaluate a positive stool-based test. Patients should check with their insurance company about this coverage.
If you have a positive stool-based test result, a follow-up colonoscopy is critical for your health.
The five-year survival rate is about 90 percent when CRC is found at an early stage before it has spread. Our doctors perform colonoscopy screenings at outpatient surgery centers around the country. Use our Locator Tool to find a GI specialist in your area.