FOR MOST PEOPLE diagnosed with rectal cancer, surgery is a standard part of treatment. Except with very early cancers, patients undergo removal of all or part of the rectum and surrounding fatty tissue—or more extensive surgery that includes removal of the anus and part of the colon. With current treatments, people with cancer confined to the rectum are 89% as likely to live for at least five years as the general population. For those with cancer that has spread outside the rectum to nearby tissue or lymph nodes, five-year relative survival is 71%.

However, after surgery, patients often experience profound, long-term issues with bowel function and sometimes sexual and urinary function. Very low rectal cancers may require a colostomy, in which the intestines are redirected to empty into a bag. For older patients or those with chronic conditions, surgery itself can be risky.

“As we’ve gained success in terms of length of life and optimal local control, it has provided the luxury of asking the question: ‘Do patients really need to suffer this much?’” says Y. Nancy You, a surgical oncologist specializing in colorectal cancer at the University of Texas MD Anderson Cancer Center in Houston.

In addition to surgery, treatment for locally advanced rectal cancer—cancer that has moved into the wall of the rectum and possibly spread to nearby tissues and lymph nodes—involves chemotherapy and radiation together, with additional chemotherapy usually given before or after surgery. In about 20% of patients, the cancer responds so well to initial chemoradiation that there is no evidence of disease on visual exam or imaging. Some cancer centers are offering these patients the option to forgo surgery and instead be watched closely for signs of recurrence—a strategy known as watch-and-wait.

In 2004, a Brazilian team published the first long-term study of watch-and-wait in the Annals of Surgery, finding that 92% of rectal cancer patients who were watched closely after a complete response to chemoradiation remained disease-free at five years. More recently, three studies—published in the April 2019 JAMA Oncology, the Feb. 7, 2020, Annals of Surgery and the December 2020 Journal of the American College of Surgeons—found that carefully selected patients were usually able to forgo surgery safely. Of the 15% to 23% who had their cancers grow back locally, most were able to have them surgically removed.

However, the JAMA Oncology study found that watch-and-wait patients who experienced local regrowth were at increased risk of distant metastasis compared to those who did not. It is unclear whether immediate surgery would have prevented these metastases. “Can we safely omit surgery when the only truly definitive way to know whether cancer cells are left is to remove the tissue and have a pathologist look at it?” You asks.

“There is a small window you have for something to be resectable,” says Najjia Mahmoud, chief of colon and rectal surgery at Penn Medicine in Philadelphia. “If cancer spreads, you face something that could have been cured but wasn’t.” For patients, watch-and-wait “takes a major commitment on their part and an understanding that the strategy might not work,” Mahmoud says. She adds that “losing control” is a worry, particularly if patients move away or don’t follow up.

Patients on a watch-and-wait regimen typically commit to visual exams every three months, frequent blood tests and some combination of CT and MRI imaging every six months for up to five years.

Researchers continue to track outcomes, refine selection criteria and investigate which therapies offer the best odds of remaining cancer-free. But for patients who can commit to frequent follow-up and tolerate some risk, watch-and-wait may be a way to preserve their rectum—and their quality of life.