Endoscopic resection of high-risk colorectal cancer not tied to worse long-term outcomes

Last Updated: 2016-12-02

By Will Boggs MD

NEW YORK (Reuters Health) - Endoscopic resection of high-risk T1 colorectal carcinoma (CRC) before surgical resection does not increase the risk of adverse long-term outcomes, according to results from the Dutch T1 CRC Working Group.

"Endoscopists were reluctant to resect polyps suspected for superficial submucosal invasion during endoscopy, in fear that it may worsen oncologic outcome," said Dr. Leon M. G. Moons from University Medical Center Utrecht in the Netherlands.

"This, among others, has resulted in surgery of large polyps containing only high-grade dysplasia based on the judgment that the polyp may be malignant," he told Reuters Health by email. "This study shows that an endoscopic resection of a polyp suspected of a superficial invasive T1 carcinoma does not seems to impair the oncologic outcome, if surgery is performed in a second stage."

The new study, online November 3 in Gut, includes 602 patients; 263 were treated with primary surgical resection and 339 with secondary surgical resection after endoscopic resection.

The rate of lymph node metastasis did not differ significantly between the primary surgery group (10.3%) and the secondary surgery group (8.3%), Dr. Moons and colleagues found in their retrospective analysis.

During an overall median follow-up of 4.3 years, there were 34 recurrences - 19 in the primary surgery group and 15 in the secondary surgery group.

The overall recurrence rate of T1 CRC treated with primary surgery was 14.7 per 1,000 person-years, which did not differ significantly from the overall rate of 9.7 per 1,000 person-years among patients treated with secondary surgery.

"These findings open the way to perform an endoscopic resection first, followed by a major surgical resection in those cases when there is a high risk of lymph node metastasis based on the presence of histologic risk factors or local recurrence," Dr. Moons said.

"This strategy may prevent major surgery in a significant number of patients, since 18-35% of the T1 CRCs will be recognized as having a low risk of lymph node metastasis (absence of histologic risk factors), and these patients can have endoscopic follow-up. Moreover, especially in those where only high-grade dysplasia is detected, major surgery is prevented, as the risk of lymph nodes metastasis is near zero," he said.

He cautioned that the approach is limited to polyps with signs of only superficial invasive carcinomas.

"An endoscopic resection of a polyp with signs of deep invasion should not be performed, as the chance of performing a curative endoscopic resection is very low. These T1 CRCs should be sent for surgery directly," he urged.

Dr. Michael B. Wallace from Mayo Clinic in Jacksonville, Florida, who recently reviewed the management of T1 CRC, told Reuters Health by email, "While endoscopic resection has been shown to be superior and more cost effective for noninvasive large lateral spreading polyps and low-risk T1 carcinomas, it remains challenging to accurately distinguish these lesions from high-risk T1 cancers based on pre-resection criteria."

"Thus, some lesions suspected of being low risk are eventually found to be high risk after endoscopic resection," he said. "This study addresses whether a 'try the less invasive, step-up approach first' approach could have negative effects. The study strongly suggests thus such an approach is safe. While it remains standard procedure to perform salvage surgery when high risk features are confirmed, the endoscopic resection does not appear to cause any problems with such salvage surgery."

"Endoscopic resection of large colorectal polyps that are suspected to be noninvasive or low-risk T1 should be offered as standard options for all patients," Dr. Wallace said. "Anecdotally, many patients are not informed that endoscopic resection is a viable option. This should change."

Dr. Shinji Yoshii from Keiyukai Sapporo Hospital in Sapporo, Japan, who recently examined risk factors for recurrence after endoscopic resection of T1 tumors, told Reuters Health by email that the new findings "may allow endoscopic resection as an excisional biopsy if we cannot determine the malignant potential such as depth of invasion or vascular invasion. By introduction of endoscopic resection as an excisional biopsy, reduction in the rate of unnecessary surgery is expected."

SOURCE: http://bit.ly/2fN0XMR

Gut 2016.