The removal of abnormal growths, or polyps, from the colon is a standard procedure performed during a colonoscopy to prevent colorectal cancer. While most polyps are small and removed in a single piece, large polyps require a specialized approach for complete and safe removal. This advanced technique is known as a piecemeal polypectomy (PP). Understanding the process and follow-up care is important for patients undergoing this procedure.
What Piecemeal Polypectomy Is and When It Is Necessary
Piecemeal polypectomy is an endoscopic method used to remove large, non-pedunculated polyps (flat or sessile). This technique is reserved for lesions measuring \(20\) millimeters or more in diameter, which cannot be safely extracted in one single piece. Attempting an “en bloc” or single-piece removal of such a large area risks damaging the deeper layers of the colon wall.
The decision to perform PP often places the procedure in the category of Endoscopic Mucosal Resection (EMR). By fragmenting the large polyp into smaller sections, the endoscopist can remove the entire lesion without resorting to invasive surgical resection. This non-surgical approach avoids the greater risks and longer recovery times associated with traditional bowel surgery, making EMR a highly effective, colon-preserving treatment option for large, benign polyps.
How the Procedure is Performed
The piecemeal polypectomy begins with submucosal injection, performed using a thin needle passed through the endoscope. A specialized solution, usually sterile saline mixed with a coloring agent and sometimes diluted epinephrine, is injected directly beneath the polyp. The injected fluid creates a cushion that lifts the polyp away from the underlying muscle layer of the colon wall, a process often referred to as the “lift sign.”
This lift acts as a protective layer, significantly reducing the risk of thermal injury or perforation to the deeper tissue during resection. Once the polyp is elevated, the endoscopist uses an electrosurgical snare to capture and resect small portions of the lesion. This process is repeated systematically, cutting the polyp into multiple fragments until the entire visible growth is removed. Any remaining microscopic tissue at the edges of the resection site may be treated with argon plasma coagulation (APC) to reduce recurrence risk.
Potential Complications and Recurrence Risk
While piecemeal polypectomy is relatively safe, the risk of immediate complications is slightly higher than with standard polypectomy. Primary immediate risks include post-polypectomy bleeding, which can occur during the procedure or up to two weeks later. There is also a small risk of perforation, though the submucosal injection technique helps guard against this.
The most notable long-term risk unique to the piecemeal technique is local recurrence of the polyp tissue. Because the polyp is removed in fragments, there is an increased chance that microscopic remnants may be left behind at the resection site. Recurrence rates are often reported to be in the range of \(5\%\) to over \(30\%\). This recurrence is generally benign and managed with further endoscopic procedures, but it necessitates a more rigorous follow-up schedule.
Post-Procedure Surveillance Schedule
Due to the elevated risk of recurrence inherent to the piecemeal technique, the surveillance schedule following a PP is much more aggressive than after a standard polypectomy. This intensified follow-up aims to detect and remove any residual or recurrent tissue before it progresses. The first follow-up procedure, often called a “check colonoscopy,” is typically scheduled three to six months after the initial resection.
During this early follow-up, the endoscopist carefully inspects the exact removal site for any signs of residual tissue. If no recurrence is found, the next surveillance colonoscopy is recommended one year later, and then every three years thereafter, provided the site remains clear. Adherence to this strict schedule is essential to ensure the complete clearance of the large polyp and preserve the colon.