Background: 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.
Objective: 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.
Design: 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).
Outcome measures: Postoperative mortality, morbidity, surgical margins, local and distant recurrence, and survival were analyzed.
Results: 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.
Limitations: This study is limited by the retrospective analysis of a database, obtained from a single institution and covering a 16-year period.
Conclusion: 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.