Patients could be spared the brutal effects of radiation

Rectal cancer researchers have pulled off a daunting feat, demonstrating in a large clinical trial that patients do just as well without radiation therapy as with it.

The results, revealed Sunday at the annual meeting of the American Society of Clinical Oncology and in a paper in the New England Journal of Medicine, could give more than 10,000 patients every year in the United States the option to forgo a cancer treatment that can have serious side effects.

The study is part of a new direction for cancer researchers, said Dr. Eric Winer, who is president of the oncology organization but was not involved in the trial.

“Now that cancer treatments have improved, researchers are starting to ask different questions,” he said. “Instead of asking how cancer therapy can be intensified, they are asking if there are elements of successful treatments that can be eliminated to provide patients with a better quality of life.”

That was why researchers took another look at the standard treatment for rectal cancer, which affects 47,500 people per year in the United States (although the class of the disease in the study affects about 25,000 Americans annually).

For decades, it was typical to use pelvic radiation. But the radiation puts women into immediate menopause and damages sexual function in men and women. It also can injure the bowel, causing issues such as chronic diarrhea. Patients risk pelvic fractures, and the radiation can cause additional cancers.

Yet radiation treatment, the study found, did not improve outcomes. After a median followup of five years, there was no difference in key measures — the length of survival with no signs that the cancer has returned, and overall survival — between the group that had received the treatment and the group that had not. And, after 18 months, there was no difference between the two groups in quality of life.

Dr. John Plastaras, a radiation oncologist at the Penn Medicine Abramson Cancer Center, said the results “certainly are interesting,” but he added that he would like to see the patients followed for a longer time before concluding that outcomes with the two treatment options were equivalent.

The trial focused on patients whose tumors had spread to lymph nodes or tissues around the bowel, but not to other organs. That subset of patients, whose cancer is deemed locally advanced, constitutes about half of the 800,000 newly diagnosed rectal cancer patients worldwide.