SAN DIEGO—At least 22% of post-colonoscopy colorectal cancer is likely related to incomplete polyp resection, researchers concluded from a root cause analysis performed on Veterans Affairs healthcare system data and presented at DDW 2025.
“Post-colonoscopy colorectal cancer can happen even after high-quality colonoscopy,” said Rahul Karna, MD, a GI fellow at the University of Minnesota, in Minneapolis, who presented the study at the ASGE Presidential Plenary (abstract Sp654c). Among the reasons proposed for PCCRC are aggressive tumor biology and lesions either missed or incompletely resected during colonoscopy.
The paucity of data that describe incomplete resection as a possible cause of PPCRC led Dr. Karna and his co-investigators to perform a root cause analysis with categorization of PPCRC based on a modified World Endoscopy Organization system. PPCRC was defined as the development of CRC within five years of colonoscopy where a precancerous polyp was detected and resected within the same bowel segment.
This single-center retrospective study evaluated data on 36 patients (average age, 71 years; mostly white males) treated at the Minneapolis VA Medical Center between 2004 and 2023. Patients with high-risk conditions, including familial CRC and inflammatory bowel disease, were excluded. The polypectomy site at the index procedure was reviewed by a blinded gastroenterologist to assess the adequacy of polypectomy.
Adequacy of Resection Difficult to Ascertain
The investigators reviewed the adequacy of the polypectomies and determined that the resections likely were incomplete for eight patients (22.2%). They confirmed complete resection for two of the 36 patients (5.5%), and for 26 patients (72.2%), they could not determine whether the resection was complete, due to a lack of photo documentation.
They then looked cecal intubation and adequate bowel prep to further assess the adequacy of the exam in the 28 patients whose resection status was complete or unknown. They found that of the two patients with a possible missed lesion after complete resection, one had a missed lesion despite an adequate exam and the other had an inadequate exam. Among the 26 patients whose polypectomy completion status was unknown, 25 had a missed lesion despite undergoing an adequate exam (69.44% of all patients). The remaining patient in that group was found to have an inadequate exam.
Follow-up Plan and Adherence
“We found that providers documented the adequacy of a follow-up plan in 95% of the patients, and practitioners subsequently noted that there was a lack of adherence to the plan in 22% of the patients. Thus, we concluded that at least 22% of post-polypectomy colorectal cancer was likely related to incomplete polypectomies,” Dr. Karna said.
“The take-home points from our study are the adequacy of polypectomy plays a key role in development of PPCRC,” he added. “Therefore, the site should be carefully reviewed to assess completion of the procedure intra-procedurally.”
“Our study highlights the inadequacy of polypectomy as a potential preventable cause of post-polypectomy CRC and reinforces the need for including polypectomy adequacy as a quality benchmark for screening colonoscopy,” said senior investigator Mohammad Bilal, MD, formerly of the University of Minnesota and now the director of Third Space Endoscopy at the University of Colorado Medicine, in Aurora. “The findings strongly suggest that gastroenterologists should assess polypectomy sites carefully to look for residual adenoma in order to prevent the future development of CRC.”
Lack of Photo Documentation Remains an Issue
Photo documentation of polypectomy is a research interest of Carol A. Burke, MD, a staff gastroenterologist at Cleveland Clinic, in Ohio, and a member of the U.S. Multi-Society Task Force on CRC, which has made recommendations for photo documentation of large polyps before and after resection (Gastrointest Endosc 2023;98[5]:797-802; DDW 2024, abstract 208).
“Classification systems to assign appropriate potential causes of post-colonoscopy colorectal cancer are established. The study from Karna and colleagues extended the assessment to post-polypectomy CRC,” Dr. Burke told Gastroenterology & Endoscopy News.
Over nearly 20 years, investigators followed patients for 5 years after a colonoscopy. Using the modified World Endoscopy Organization system they deemed 22% of PPCRC cases to be the result of incomplete polypectomy, yet 72% (26/36) of resected polyps had no associated photo documentation.
“This study reinforces a critical but often overlooked gap in colonoscopy practice: the absence of photo documentation of critical features. The lack of post-polypectomy imaging corroborates previous work from the Cleveland Clinic,” Dr. Burke said. “Without visual confirmation of key aspects of colonoscopy and polypectomy, the true quality of colonoscopy cannot be established.”
—Caroline Helwick
Dr. Bilal reported financial relationships with Boston Scientific, Cook and Steris. Drs. Burke and Karna reported no relevant financial disclosures.
This article is from the July 2025 print issue.