Stapling of the ileal pouch-anal anastomosis, with preservation of the anal transitional zone, remains controversial due to the potential risk of dysplasia and cancer.
However, natural history, and optimal treatment of anal transitional zone dysplasia, 10 or more years after surgery are unknown.
In this study, a research team from Cleveland, Ohio, established the risk of dysplasia in the anal transitional zone. They also assessed the outcome of a conservative management policy for anal transitional zone dysplasia, with a minimum of 10 years' follow-up after ileal pouch-anal anastomosis.
The team studied 289 patients undergoing anal transitional zone-sparing stapled ileal pouch-anal anastomosis for IBD, between 1986 and 1990.
They included 178 patients undergoing anal transitional zone-sparing ileal pouch-anal anastomosis, who were studied with serial anal transitional zone biopsies for at least 10 years, postoperatively.
Median follow-up was 130 months.
| No cancer was found in the anal transitional zone during the study period.|
|Diseases of the Colon and Rectum|
The researchers found that anal transitional zone dysplasia developed in 8 patients, between 4 and 123 months after surgery.
The team identified no association with gender, age, preoperative disease duration, or extent of colitis. However, the risk of anal transitional zone dysplasia was associated with cancer or dysplasia as a preoperative diagnosis, or in the proctocolectomy specimen.
Dysplasia was high grade in 2 patients and low grade in 6.
Of these, 2 patients with low-grade dysplasia, on 2 or more occasions after detection of low-grade dysplasia, underwent completion mucosectomy and perineal pouch advancement with neo-ileal pouch-anal anastomosis.
Of the patients with high-grade dysplasia, 1 was to undergo completion mucosectomy, however this was not found to be technically feasible. Instead, partial mucosectomy, with vigorous anal transitional zone biopsy, was performed with close postoperative surveillance. Biopsies were negative for dysplasia.
The second high-grade dysplasia underwent examination under anesthesia with negative anal transitional zone biopsies and will be kept under close surveillance.
The team found no cancer in the anal transitional zone during the study period.
The research team treated the 4 other patients with low-grade dysplasia expectantly, and have been dysplasia-free for a median of 119 months.
Dr Feza Remzi’s team concluded, “Anal transitional zone dysplasia after stapled ileal pouch-anal anastomosis is infrequent and is usually self-limiting”.
“Anal transitional zone preservation did not lead to the development of cancer in the anal transitional zone with a minimum of 10 years of follow-up.”
“Long-term surveillance is recommended to monitor dysplasia.”
“If repeat biopsy confirms persistent dysplasia, mucosectomy with perineal pouch advancement and neo-ileal pouch-anal anastomosis is recommended.”