Risk factors influencing sphincter preservation in laparoscopic radical rectal cancer surgery

Table 1 Comparison of clinical data between sphincter-preserved and sphincter-unpreserved groups, n (%)

Factors	Sphincter-preserved group (n = 150)	Sphincter-unpreserved group (n = 29)	Statistics	P value
Age (years)	67 (59, 72)	65 (57, 73)	0.719	0.472
Sex			0.001	0.985
Male	98 (65.3)	19 (65.5)
Female	52 (34.7)	10 (34.5)
Residence			3.951	0.047
Rural	63 (42.0)	18 (62.1)
Urban	87 (58.0)	11 (37.9)
BMI (kg/m2)	22.8 ± 3.2	22.5 ± 3.3	0.587	0.558
Time since onset of first symptoms or diagnosis (months)	2 (1, 6)	3 (2, 7)	1.225	0.220
Duration of preoperative care (days)	7 (5, 9)	7 (6, 10)	0.925	0.355
Preoperative bowel preparation time (days)	6 (4, 7)	6 (5, 7)	0.731	0.465
Colonic polyps	72 (48.0)	8 (27.6)	4.097	0.043
Rectal polyps	20 (13.3)	1 (3.4)	1.438	0.230
Tumours with bleeding	107 (71.3)	20 (69.0)	0.066	0.797
Tumours causing obstruction	22 (14.7)	1 (3.4)	1.821	0.177
Neoadjuvant chemotherapy	20 (13.3)	10 (34.5)	6.349	0.012
Preoperative radiotherapy	16 (10.7)	7 (24.1)	2.827	0.093
History of hypertension	53 (35.3)	12 (41.4)	0.384	0.535
Diabetes mellitus	22 (14.7)	7 (24.1)	0.984	0.321
Coronary artery disease	24 (16.0)	2 (6.9)	0.972	0.324
Peripheral vascular lesions of the lower extremities	11 (7.3)	5 (17.2)	1.840	0.175
History of previous abdominal surgery	41 (27.3)	6 (20.7)	0.554	0.457
History of recent aspirin use	22 (14.7)	3 (10.3)	0.104	0.747
Smoking history	26 (17.3)	6 (20.7)	0.186	0.666
Alcohol consumption history	20 (13.3)	3 (10.3)	0.019	0.891
Preoperative hypoproteinemia	17 (11.3)	5 (17.2)	0.334	0.563
Preoperative anemia	13 (8.7)	5 (17.2)	1.141	0.285
Pelvic effusion	48 (32.0)	8 (27.6)	0.220	0.639
Clinical stage			1.383	0.240
0/I/II	95 (63.3)	15 (51.7)
III/IV	55 (36.7)	14 (48.3)
Tumour T stage			0.030	0.863
Tis/T1/T2	49 (32.7)	9 (31.0)
T3/T4	101 (67.3)	20 (69.0)
N stage			0.390	0.532
N-	87 (58.0)	15 (51.7)
N+	63 (42.0)	14 (48.3)
Degree of tumour differentiation			4.003	0.144
Medium differentiation	124 (82.7)	22 (75.9)
High differentiation	17 (11.3)	2 (6.9)
Low differentiation	9 (6.0)	5 (17.2)
Mucinous adenocarcinoma	14 (9.3)	7 (24.1)	3.813	0.051
Vascular invasion	38 (25.3)	7 (24.1)	0.018	0.892
Nerve invasion	75 (50.0)	22 (75.9)	6.548	0.011
Preoperative fever of ≥ 37 °C	31 (20.7)	10 (34.5)	2.627	0.105
ASA grading			0.283	0.595
I/II	112 (74.7)	23 (79.3)
III/IV	38 (25.3)	6 (20.7)
Tumour height			69.652	< 0.001
Upper rectum	55 (36.7)	1 (3.4)
Middle rectum	73 (48.6)	2 (6.9)
Lower rectum	22 (14.7)	26 (89.7)
Maximum transverse tumour diameter (cm)	3.5 (2.8, 4.6)	3.8 (3.2, 4.4)	0.502	0.616
CEA (ng/mL)	3.25 (1.60, 10.55)	5.79 (3.21, 10.41)	2.444	0.015
CA19-9 (ng/mL)	13.65 (8.02, 21.43)	21.61 (12.28, 24.80)	2.299	0.022
ALB (g/L)	38.0 ± 4.1	38.0 ± 3.8	0.001	0.999
GLU (mmol/L)	4.89 (4.35, 5.63)	5.24 (4.61, 5.33)	0.849	0.396
Potassium (mmol/L)	3.9 (3.7, 4.2)	3.9 (3.8, 4.2)	0.527	0.598
PT-T (second)	12.3 (11.6, 12.9)	12.3 (11.7, 12.6)	0.031	0.975
DD (mg/L)	0.77 (0.62, 1.11)	0.88 (0.72, 1.72)	1.874	0.061
WBC (109/L)	5.38 (4.54, 6.41)	5.75 (5.07, 5.82)	1.106	0.269
PLT (109/L)	203 (166, 239)	204 (188, 222)	0.672	0.502

BMI: Body mass index; TNM: Tumour-node-metastasis; ASA: American Society of Anaesthesiologists; CEA: Carcinoembryonic antigen; ALB: Albumin; GLU: Glucose level; PT-T: Prothrombin time; DD: D-dimer levels; WBC: White blood cell count; PLT: Platelet count.

Table 2 Logistic regression analysis of sphincter preservation in laparoscopic radical rectal cancer surgery

Variable	β	P value	OR	95%CI
Residence	-1.046	0.131	0.351	0.090-1.367
Colonic polyps	-2.207	0.006	0.110	0.023-0.535
Neoadjuvant chemotherapy	1.848	0.302	6.347	0.190-211.759
Preoperative radiotherapy	0.807	0.674	2.241	0.052-95.916
Mucinous adenocarcinoma	2.504	0.009	12.230	1.847-80.999
Nerve invasion	1.836	0.012	6.272	1.499-26.247
Tumour height
Upper rectum			Refence
Middle rectum	-0.301	0.837	0.740	0.042-13.001
Lower rectum	5.292	< 0.001	198.820	13.665-2892.686
CEA	0.021	0.390	1.021	0.974-1.070
CA19-9	0.015	0.240	1.015	0.990-1.041
DD	0.013	0.755	1.013	0.934-1.099

TNM: Tumour-node-metastasis; CEA: Carcinoembryonic antigen; DD: D-dimer levels; OR: Odds ratio; CA19-9: Carbohydrate antigen 19-9.