Predictive model for sphincter preservation in lower rectal cancer

Table 5 Studies on predictive factors for sphincter-preserving surgery in low-lying rectal cancer

Ref.	Types of study	Sample size	Predictive factors
[14]	Retrospective	540	Younger age. Good performance status. cT1-T2. Higher relative lymphocyte value. Lower CRP value. Longer interval between CRT and surgery
[15]	Retrospective	268	Younger age at diagnosis, proximal location in the rectum, nonfixed tumor, and institution experience
[62]	Retrospective	42	BMI, distance of tumor from anal verge, diameter of upper pubis to coccyx
[174]	Retrospective	230	Cancers within 4 cm of anal verge, surgeon procedure volume, neoadjuvant radiotherapy
[175]	Retrospective	409	CRM
[176]	Retrospective	1020	Preoperative CEA ≥ 10 ng/ml. T4 stage, N stage, low rectal tumor, advanced age, ASA ≥ III, and male sex
[176]	Retrospective	330	Age > 40. Female sex. Well differentiated tumor. cT1-T2. Distance of tumor from anal verge. Total infiltrated circumference. BMI
[177]	Retrospective	47713	Age < 60, female gender, and white race, high procedural volume
[178]	Retrospective	541	Tumor height prior to CRT higher than 4.5 cm, non mucinous or signet ring adenocarcinoma, pathological T stage higher than T3, preoperative CRT
[179]	Retrospective	403	Tumor location, tumor markers, ASA score, T4 stage, lymph node metastasis, distant metastasis
[180]	Metanalysis	3026	Older age especially > 65 years of age, male sex, ASA score ≥ 3, comorbidity, and distant metastasis
[181]	Retrospective	331	Neoadjuvant chemoradiotherapy, cT3 stage, distant metastasis
[182]	Retrospective	179	neoadjuvant chemotherapy, preoperative radiotherapy, mucinous adenocarcinoma, nerve invasion, and tumour height, CEA

CRT: Chemoradiotherapy; ASA: American Society of Anesthesiologists; CRM: Circumferential resection margin; CRP: C-reactive protein; CEA: Carcinoembryonic antigen; BMI: Body mass index.