LOS ANGELES – A multicenter of patients who had low anterior resection with stapled anastomosis for rectal cancer found no clinical or economic benefit in routinely sending anastomotic doughnuts for histopathological evaluation.
“Several small studies outside the United States have found no benefit in histologic examination of anastomotic stapler doughnuts,” lead study author Dr. Jeremy Sugrue said at the annual meeting of the American Society of Colon and Rectal Surgeons. “We wanted to see if this held true in our population.”
Dr. Sugrue, of the division of colon and rectal surgery in the department of surgery at the University of Illinois at Chicago, and his associates performed a retrospective review of 486 patients who underwent a low anterior resection with stapled anastomosis for rectal cancer between 2002 and 2015 at three medical institutions. The primary outcome was pathologic findings in the doughnuts and their impact on patient management. Secondary outcomes included tumor characteristics that may influence how often a surgeon may send a doughnut to pathology, along with approximate cost.
The mean age of the 486 patients was 60 years, 55% were male, and the mean gross distal margin of the primary tumor specimen was 2.9 cm. “The majority of tumors were located in the middle rectum, and the rest were evenly distributed between the lower rectum, upper rectum, and rectosigmoid regions,” said Dr. Sugrue, who is a general surgery resident. About half of the patients received neoadjuvant radiation or chemotherapy.
Benign findings were found in 33 patients. Among these, 16 had inflammatory changes, including 12 who had nonspecific changes, 3 who had changes from radiation, and 1 had inflammatory bowel disease changes. In addition, 13 patients with benign findings had polyps in their doughnuts (10 hyperplastic and 3 adenomatous), while 4 patients had miscellaneous changes including two cases of vessel micro calcification, one case of diverticuli, and one case of melanosis coli.
Among the 412 patients with malignant findings, 410 (99.5%) had no cancer in the doughnuts and no cancer at the distal resection margin in the primary tumor specimens. “In the two patients where we found cancer in the doughnuts, these patients also had a positive distal margin,” Dr. Sugrue said. “We did not find any patients with a positive distal margin and a negative doughnut. Likewise, we did not find any patients with a negative distal margin or an unexpectedly positive doughnut.”
The researchers also found that patients with low rectal tumors were significantly more likely to have their doughnut sent to pathology, compared with those with rectosigmoid tumors. “However, when we looked at distal margin comparing patients who had doughnuts reported on pathology with those who did not, there was no statistically significant difference,” Dr. Sugrue said. After averaging pathology professional fees and technical fees across all three institutions, he and his associates determined that doughnuts add $643 in cost when processed by pathology as a unique specimen.
Limitations of the study, he said, include its retrospective design, “which inherently introduces selection bias, and we did not perform a precise cost-benefit analysis.”
Dr. Sugrue reported having no financial disclosures.