Large polyps and superficial T1a colon cancers often can be removed endoscopically, but many are still being referred for more intensive surgical resection.
"The technology and expertise to remove large polyps and superficial cancers from the colon is available fairly broadly in the U.S., but it's not being applied," according to Michael Wallace, MD, Professor of Medicine at the Mayo Clinic in Jacksonville, Fla., and Editor-in-Chief, of the journal Gastrointestinal Endoscopy.
Historically, large polyps of 2 cm or more in diameter and superficial cancers were treated surgically by removing the affected segment of the colon. But surgical resection often comes with fairly significant complications, more hospital time, and increased costs.
Over the past 2 decades, endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) have become more commonly available and provide ways that are effective and less invasive.
Between 1-2 percent of all polyps are classified as large, and generally can't be removed during a screening colonoscopy. According to Wallace, it can take about an hour to remove a 2-4 cm polyp, and 2-3 hours to remove polyps 4 cm or bigger.
Among patients who undergo surgery for nonmalignant colorectal polyps, studies suggest upwards of 14 percent will have at least one major short-term postoperative event (Gastrointest Endosc 2018; doi:10.1016/j.gie.2017.03.1550). Complications from partial colectomy can include postoperative infection, wound dehiscence, higher readmission and reoperation rates, need for an ostomy, and sometimes death.
It is increasingly recognized that even polyps considered to be benign, over the long term, can eventually become cancerous. Polyp removal is an outpatient procedure, whereas patients who undergo surgical resection typically spend at least 2-3 days in hospital.
Colon Surgery Rates
"During the past 10-20 years, the techniques to remove large polyps through colonoscopy have been developed and refined. There are now many centers in the U.S. that perform it. But there is still published data that show the number of colon surgeries for benign polyps has not decreased. Many patients are still getting unnecessary surgery for these large polyps," Wallace told Oncology Times.
Indeed, one study published in Gastroenterology by researchers from the University of North Carolina analyzed national data and found that surgery for nonmalignant colorectal polyps is not only common in the U.S., but rates have actually increased over the past 14 years (2018; doi:10.1053/j.gastro.2018.01.003). The study used data from the Healthcare Cost and Utilization Project National Inpatient Sample for 2000 through 2014.
The researchers identified 1,230,458 surgeries for nonmalignant colorectal polyps and colorectal cancer in the U.S. Of these, 25 percent (over 300,000) were for nonmalignant colorectal polyps, and data showed the incidence of surgery for these increased significantly from 5.9 per 100,000 adults in 2000 to 9.4 in 2014. At the same time, the incidence of surgery for colorectal cancer significantly decreased, from 31.5 to 24.7 surgeries per 100,000 adults.
Cost-Effectiveness
Endoscopic removal is proving far more cost-effective than surgical resection. One study published in Gastrointestinal Endoscopy in 2016 by Law and colleagues showed endoscopic removal of a complex colon polyp was $5,570 per patient compared to $18,717 per patient for laparoscopic removal (2016;83(6):1248-1257).
Another 2016 cost-analysis study in Clinical Gastroenterology and Hepatology compared the costs incurred in patients who had large (mean of 36 mm) laterally spreading lesions in the colon and rectum removed by either EMR or surgery (2016; doi:10.1016/j.cgh.2015.08.037). EMR was performed in 1,353 patients for a total cost of $6,316,593 and total inpatient hospitalization length of stay was 1,180 days. For the same number of patients, the total cost predicted for the surgical management group was $16,601,502, with a total inpatient hospitalization length of stay of 4,986 days.
Performing EMR & ESD
The reasons for referrals of patients with large polyps to surgeons by gastroenterologists may be largely due to historical habits since it used to be the norm, Wallace said. But now, there's no reason gastroenterologists can't refer these patients to high-volume centers which generally have gastroenterologists who have the additional training and certification do perform EMR and ESD.
A website created by journalist Jim Sease, who had a large polyp removed, has an extensive list of centers which have the expertise (http://www.sease.com/polyp/emr.html). "I refer patients to this informative website all the time," he said.
Nearly every region in the U.S. has high-volume centers with at least one gastroenterologist qualified to do these procedures. Wallace admits large polyps can be tricky to remove and it takes training, along with a high volume of cases, to become skilled. The American Society for Gastrointestinal Endoscopy has a certification program, and supervised training for this is increasingly done during fellowship training.
As for the endoscopic approaches, EMR is used for polyps that sit on the mucosal layer, while ESD can be used for T1a tumors that may sit no deeper than the submucosal layer.
With ESD "you can remove a noninvasive polyp of any size in a single piece. You make an incision around the perimeter of the polyp, then you dissect underneath it so when the polyp comes out it's all in a single piece. That's vital if it's a cancer. You want to be 100 percent sure you got everything out by looking at the margin," Wallace said.
With EMR, a benign polyp is often taken out in multiple pieces, especially if it's very large. "This is fine for noninvasive polyps. But it's not appropriate to remove an invasive polyp in multiple pieces," he noted.
There are a variety of features of polyps that indicate whether they are surface or invasive. Ones with a broad base can be challenging because of a risk of injuring blood vessels or perforating the colon. Large margins around the polyp are also needed.
"Carefully examine the polyp to make sure you can define the edges. Sometimes the edges are quite subtle," Wallace explained. "Ensure you remove the entire polyp and have a margin of tissue around it without perforating or damaging the blood vessels around it."
The bigger a polyp is the trickier it can be to remove. Also, certain locations make removal more challenging. "If it's on a tight angled area or fold, its more challenging. If it's at either the proximal boundary of the ileocecal valve or at the very lower end near the anal opening, that can be difficult because of the tight spaces one has to work in," Wallace said.
Also, there needs to be a strong, trained team to help make these procedures successful. "It's not just the physician's skill, it's the whole team," he concluded.
Pippa Wysong is a contributing writer.