Comparison of anal function and quality of life after conformal sphincter preservation operation and intersphincteric resection of very low rectal cancer: a multicenter, retrospective, case-control analysis.

"Declarations Conflict of interestThe authors declare that they have no competing interest. Conflict of interest The authors declare that they have no competing interest."

"Funding This study was supported by Joint Research Projects of Shanghai Municipal Hospital Emerging Cutting-edge Technology [Grant number SHDC12016122]; the First Affiliated Hospital of Naval Medical University "234 Subjects Peak Climbing Plan" (2019YXK032); National Key Clinical Specialty Construction Project (2012); Biomedicine Guidance Project of Shanghai Science and Technology Committee (134119a1400)."

"The clinical data of patients who underwent CSPO and ISR for very low rectal cancer was collected in Changhai Hospital Affiliated to Naval Medical University (n = 117) and Huashan Hospital Affiliated to Fudan University (n = 66), respectively, from August 2011 to April 2020. This study was approved by the Ethics Committee of the First Affiliated Hospital of Naval Medical University (committee’s reference number CHEC2022-021) and followed the precepts established by the Helsinki Declaration. Each patient signed the informed consent. The work has been reported in line with the STROCSS criteria []. This research was retrospectively registered in the Chinese Clinical Trial Register (ChiCTR2300070971)."