Retrospective study of the functional and oncological outcomes of conformal sphincter preservation operation in the treatment of very low rectal cancer

Abstract

Background: Conformal sphincter preservation operation (CSPO) is a new surgical procedure for very low rectal cancers (within 4-5 cm from the anal verge). CSPO preserves more of the dentate line and distal rectal wall and also avoids injuring nerves in the intersphincteric space, resulting in satisfactory anal function after resection. The aim of this study was to analyze the short-term surgical results and long-term oncological and functional outcomes of CSPO.

Methods: Consecutive patients with very low rectal cancer, who had CSPO between January 2011 and October 2018 at Changhai Hospital, Shanghai were included. Patient demographics, clinicopathological features, oncological outcomes and anal function were analyzed.

Results: A total of 102 patients (67 men) with a mean age of 56.9 ± 10.8 years were included. The median distance of the tumor from the anal verge was 3 (IQR, 3-4) cm. Thirty-five patients received neoadjuvant chemoradiation (nCRT). The median distal resection margin (DRM) was 0.5 (IQR, 0.3-0.8) cm. One patient had a positive DRM. All circumferential margins were negative. There was no perioperative mortality. The postoperative complication rate was 19.6%. The median duration of follow-up was 28 (IQR, 12-45.5) months. The local recurrence rate was 2% and distant metastasis rate was 10.8%. The 3-year overall survival and disease-free survival rates were 100% and 83.9%, respectively. The mean Wexner incontinence and low anterior resection syndrome scores 12 months after ileostomy reversal were 5.9 ± 4.3, and 29.2 ± 6.9, respectively.

Conclusions: For patients with very low rectal cancers, fecal continence can be preserved with CSPO without compromising oncological results.

Keywords: Disease-free survival; Follow-up studies; Local; Low anterior resection syndrome; Margins of excision; Neoplasm recurrence; Postoperative complications; Rectal neoplasms; Surgery.

Fig. 1

The CSPO technique. a, b The tumor was pulled out of the anus through the rectal lumen, the distal dissection line was made at least 1 cm below the inferior tumor margin, preserving more rectum on the opposite tumor side. c The rectal stump was closed by manual interrupted sutures. d The stapler was inserted to the upper tip of the rectal stump to preserve more rectum wall. e, f The hiatal ligament

Fig. 2

Drawing of the transection lines for ISR (blue lines). Total intersphincteric resection (total-ISR) is defined as an internal sphincter resection at the intersphincteric groove, subtotal-ISR is between the dentate line (DL) and ISG, and partial-ISR is at the DL. But the CSPO stops at the entrance of ISS, and resection line in the internal sphincter is inclined and conformed to the tumor edge

Fig. 3

Colonoscopy a Preoperative colonoscopy shows that the mass is 1 cm above the dentate line. b Five months postoperatively, colonoscopy shows the anastomotic line 2–3 cm away from the dentate line

Fig. 4

Survival after CSPO. a Disease-free survival, b overall survival

Fig. 5

Flow chart of patients

Fig. 6

Stoma free survival of patients after CSPO. a Stoma free survival of all the patients after CSPO. b Stoma free survival for patients with and without nCRT, p = 0.23