ASK THE DOCTORS: PROMISING STUDY ON RECTAL CANCER HAS NARROW SCOPE

Dear Doctors: I saw on the evening news that some doctors in New York City actually cured rectal cancer with a new drug. My dad has rectal cancer, and when I asked his doctors about this drug, they hadn't heard anything about it. Are the news stories wrong?

Dear Reader: We believe you're referring to the findings from a small study that were recently published in the New England Journal of Medicine. However, the details you've mentioned aren't quite accurate. To clear things up, let's take a closer look at the study.

You're correct that this research was conducted by doctors at Memorial Sloan Kettering Cancer Center in New York City. And while it's also correct that the study focused on rectal cancer, the scope was actually quite narrow. Participation in the study was limited to patients over the age of 18 who had been diagnosed with early stage rectal cancer, and who had not yet undergone any type of treatment. Their tumors also shared a certain kind of genetic anomaly that appears in fewer than 10% of patients and makes this subset of rectal cancer difficult to treat. As news stories have pointed out, the drug the patients received performed remarkably well, and the results have generated widespread interest.

Over the course of six months, each of the 12 patients accepted into the study received nine infusions of an intravenous immunotherapy drug. Known as dostarlimab, it's fairly new, having been approved by the FDA for use as a cancer treatment in early 2021. The drug works by blocking the activity of a protein produced by the cancer cells, which is able to derail the body's immune response.

At the end of six months of treatment, each patient underwent numerous tests to assess their cancer. These included several types of imaging scans, an endoscopy, biopsies and physical exams. Researchers were startled when no trace of cancer was detected in any of the 12 study participants.

Rectal cancer is curable, particularly when caught in the early stages. Traditional treatment routinely includes surgery, radiation therapy and chemotherapy. These treatments can not only be grueling, but also can have lasting effects. Patients may be left with nerve damage, irreversible bladder or bowel dysfunction or sexual dysfunction. Uterine scarring can make pregnancy difficult or impossible. When a tumor is located close to the rectum, surgery to remove it will leave the patient dependent on a colostomy bag.

Although the immunotherapy drug also produced side effects in three-fourths of the study participants, they appear to have been less severe than with traditional treatments. These included nausea, fatigue, rash and persistently itchy skin.

The patients in the study will now undergo several years of follow-up and observation. They will be monitored to see if their tumors recur, and whether or not the cancer metastasizes and appears elsewhere in the body. Should any of the patients have a recurrence, they will receive immediate treatment. Meanwhile, this research has opened the door for new studies to investigate if other types of cancer affected by this genetic anomaly may also respond to the drug.