HOUSTON – Patients who achieve complete clinical responses after neoadjuvant therapy for locally advanced rectal cancer may, in many cases, be safely spared the trauma and morbidity of total mesorectal excision.

That’s the opinion of investigators at Memorial Sloan Kettering Cancer Center, New York, who found that nearly two-thirds of patients followed with nonoperative management (NOM) had durable complete clinical remissions (cCR) for at least 4 years.

Disease-specific survival and overall survival rates among patients who had nonoperative management were similar to those seen in patients with pathologic complete responses (pCR), defined as no viable tumor cells in the resected specimen.

“We know that there is a very good overall and disease-free survival associated with a [pCR]. Clinical complete response is also associated with pathologic complete response. In that regard, this brings up the question: Is an operation always necessary in these patients?” Dr. Jesse Joshua Smith of the cancer center said at the annual Society of Surgical Oncology Cancer Symposium.

Dr. Smith and colleagues conducted a review of their center’s experience to date with NOM for patients with locally advanced rectal cancer, asking whether the data support the approach as oncologically safe and effective for organ preservation.

They identified 442 patients with rectal cancer treated with neoadjuvant chemotherapy from 2006 through 2014 and compared results for 73 who achieved a cCR and were followed with nonoperative management with those of 72 patients who had a pCR following total mesorectal excision.

Demographic and clinical characteristics between the groups were generally similar, although patients in the pCR group were significantly younger (58 years vs. 65 years, P = .01), had a greater tumor distance from the anal verge (median of 6 cm vs. 5.25 cm, P = .02), and higher proportions of clinical stage II (32% vs. 24%) and III (66% vs. 62%, P = .02).

Among the 73 patients managed with NOM, 54 had durable cCR at 4 years. Of the remaining 19 with local tumor regrowth, 2 had local excisions with no further recurrence and 17 went on to have rectal resections. The total number of patients with rectal preservation in this group was 56 (77%).

Of the 19 patients in the conservatively managed group who had local regrowths, all but three of the recurrences were detected within 13 months.

As noted before, neither disease-specific survival nor overall survival were significantly different between patients managed with NOM or with total mesorectal excision.

There were numerically more distant recurrences at both 1 and 4 years among patients treated with NOM compared with total mesorectal excision (7% vs. 2%, and 17% vs. 9%, respectively), but the differences were not statistically significant, the authors found.

Dr. Smith noted that patients who are offered the option of NOM have a discussion with the surgeon emphasizing that the practice is nonstandard management, carries about a 25% risk of local regrowth, and requires increased endoscopic and radiographic surveillance. Patients also are informed about the risks of salvage abdominoperineal resection or extended resections, and about the potential risk of compromising cure.

The study was supported in part by the Berezuk Colorectal Cancer Fund. Dr. Smith reported having no disclosures.