The ASCO Post - Observation Appropriate for Some Patients With Rectal Cancer Following Neoadjuvant Therapy

Observation Appropriate for Some Patients With Rectal Cancer Following Neoadjuvant Therapy

The ASCO Post

The investigators compared outcomes among 145 patients with stage I to III rectal cancer, 73 of whom achieved a clinical complete response (no detectable tumor by clinical exam, endoscopy, or imaging) after neoadjuvant chemoradiation therapy and were treated nonoperatively.

This cohort was compared with 72 patients treated conventionally who achieved a pathologic complete response and underwent total mesorectal excision.

After a median follow-up of 3.5 years, 74% of the 73 patients who were observed achieved a durable and sustained clinical complete response, and no surgical intervention was required. For the 19 patients (26%) who had local regrowth of tumor, salvage surgery was undertaken, and all were successful. One patient had tumor recurrence after resection of local tumor regrowth, yielding a local control rate of 98%, Dr. Smith reported.

In addition, 77% of patients were able to complete treatment with rectal preservation, and this conservative approach did not compromise outcomes, Dr. Smith emphasized.

The disease-specific and overall survival rates were similar between the two groups. The rate of distant tumor recurrence was 13% with nonoperative management and 7% with surgery following a pathologic complete response, which was not significantly different.

At the press briefing, Dr. Paty commented that by comparing patients with a clinical complete response with those with a pathologic complete response, “We set the bar very high and found that nonoperative management appears to compare favorably.”

He acknowledged that “practicing ‘watch and wait’ can be difficult for surgeons,” but this approach is being increasingly accepted. “Centers are adopting it, and many leaders in clinical trials of rectal cancer recognize that this option is not only reasonable, but perhaps it is necessary to inform patients that it is an option,” Dr. Paty said.

Dr. Smith stressed the importance of a careful discussion between the patient and the surgeon and obtaining consent with both parties acknowledging the risks, possible benefits, and alternatives compared with uniform offering of total mesorectal excision. 

“Patients need to know this is nonstandard management, off protocol; that there is a 25% risk of local tumor regrowth; that nonoperative management requires frequent endoscopic and radiographic surveillance; that there’s a risk for salvage abdominal perineal resection or extended resection; and that there’s a potential risk of compromising cure,” he said.

Most local regrowth occurs within 12 to 13 months and can be salvaged successfully, he indicated. “However, prospective trials are needed to confirm these findings, and they are in progress,” he said.

A phase II multicenter randomized trial studying the use of neoadjuvant treatment in locally advanced rectal cancer patients and the use of nonoperative management in those with clinical complete response is ongoing at Memorial Sloan Kettering led by the Colorectal Service, which includes Julio Garcia-Aguilar, MD, Philip Paty, MD, Karyn A. Goodman, MD, Mark Gollub, MD, and Leonard Saltz, MD (ClinicalTrials.gov identifier NCT02008656). ■