Low rectal cancer: classification and standardization of surgery

Surgical treatment of low rectal cancer is controversial, and one of the reasons is the lack of definition and standardization of surgery in low rectal cancer.

We classified low rectal cancers in 4 groups with the aim of demonstrating that most patients with low rectal cancer can receive conservative surgery without compromising oncologic outcome.

Patients with low rectal cancer <6 cm from anal verge were defined in 4 groups: type I (supra-anal tumors: >1 cm from anal ring) had coloanal anastomosis, type II (juxta-anal tumors: <1 cm from anal ring) had partial intersphincteric resection, type III (intra-anal tumors: internal anal sphincter invasion) had total intersphincteric resection, and type IV (transanal tumors: external anal sphincter invasion) had abdominoperineal resection. Patients with ultra-low sphincter-preserving surgery (types II-III) were compared with those with conventional sphincter-preserving surgery (type I).

Postoperative mortality, morbidity, surgical margins, local and distant recurrence, and survival were analyzed.

Of 404 patients with low rectal cancer, 135 were type I, 131 type II, 55 type III, and 83 type IV. There was no difference in local recurrence (5% to 9% vs 6%), distant recurrence (23% vs 23%), and disease-free survival (70%-73% vs 68%) at 5 years between ultra-low (types II-III) and conventional (type I) sphincter-preserving surgery. Predictive factors of survival were tumor stage and R1 resection but not the type of tumor or type of surgery.

This study is limited by the retrospective analysis of a database, obtained from a single institution and covering a 16-year period.

Classification of low rectal cancers and standardization of surgery permitted sphincter-preserving surgery in 79% of patients with low rectal cancer without compromising oncologic outcome. This new surgical classification should be used to standardize surgery and increase sphincter-preserving surgery in low rectal cancer.