A retrospective review of clinical data on 145 patients with stage I-III rectal cancer indicates that patients whose tumors had a complete response after treatment with chemoradiation and systemic chemotherapy had similar four-year survival rates regardless of whether they had immediate surgery or pursued a watchful waiting surveillance approach. The findings add to growing evidence suggesting that, with frequent follow-up exams after initial chemotherapy and radiation, select patients with rectal cancer can achieve excellent outcomes while avoiding the risks and complications of rectal surgery. The study was presented at the 2015 Gastrointestinal Cancers Symposium in San Francisco.

"We believe that our results will encourage more doctors to consider this watch and wait approach in patients with clinical complete response as an alternative to immediate rectal surgery, at least for some patients," said senior study author Philip Paty, M.D., a surgical oncologist at the Memorial Sloan-Kettering Cancer Center in New York, NY. "From my experience, most patients are willing to accept some risk to defer rectal surgery in hope of avoiding major surgery and preserving rectal function."

Dr. Paty stated that in about 40 to 50 percent of patients with stage I rectal cancer and 30 to 40 percent of patients with stage II-III cancer, tumors disappear clinically after initial treatment with chemoradiation and systemic chemotherapy. He suggests that those patients are potential candidates for the watch and wait approach. By avoiding rectal surgery, patients are spared of its risks, including impaired bowel and sexual function, which can substantially diminish quality of life.

In the present report, researchers retrospectively analyzed data that were collected at Memorial Sloan-Kettering Cancer Center between 2006 and 2014. Patients with stage I-III rectal cancer who received radiation and chemotherapy and who experienced complete tumor regression were either followed by watchful waiting (non-surgical management) or taken for rectal surgery. Patients undergoing the watchful waiting approach were initially followed at three- to four-month intervals by digital rectal and endoscopic exams and at six-month intervals by cross-sectional imaging. Median follow-up in this report is 3.3 years.

Rectal surgery was deferred in 73 patients who achieved a clinical complete response after chemotherapy and radiation. Among those 73 patients, 74 percent experienced durable tumor regression and avoided rectal surgery; 26 percent eventually underwent rectal surgery to treat tumor regrowth.

In a non-randomized comparison, researchers found that the outcomes achieved in this group of patients were similar to the outcomes of 72 patients who underwent standard rectal surgery and experienced a pathologic complete response; the four-year overall survival rate was 91 percent in the no-surgery group vs. 95 percent in the standard surgery group. No significant differences were noted in the number of distant recurrences between the two groups.

According to the authors, this is one of the largest experiences of its kind, building on prior evidence from research conducted in Brazil and the Netherlands. Non-surgical management of rectal cancer is becoming increasingly accepted as a standard option worldwide. A prospective phase II study has recently begun enrolling patients, and non-surgical management will be offered to patients whose tumors fully disappear after initial chemotherapy and radiation.

"Avoiding surgery has the potential to significantly improve quality of life for patients, for example by avoiding a colostomy. Longer follow-up is needed, however, to be sure that this approach does not result in higher cancer recurrences. A prospective study in the United States evaluating this important issue is now enrolling patients," said Smitha S. Krishnamurthi, M.D., an ASCO spokesperson.

This work was supported in part by funding from the Berezuk Colorectal Cancer Fund.