Intraoperative intraperitoneal chemotherapy increases the incidence of anastomotic leakage after anterior resection of rectal tumors

Table 1 Patient-related variable

Variable	Intraoperative chemotherapy (+) (n = 171)	Intraoperative chemotherapy(-) (n = 306)	P-value
Age (yr, mean ± SD)	58.1 ± 10.1	59.1 ± 11.3	0.627
Sex, n (%)			0.829
Male	109 (63.7)	192 (62.7)
Female	62 (36.3)	114 (37.3)
BMI (kg/m2, mean ± SD)	24.4 ± 3.1	23.9 ± 3.4	0.123
Smoking, n (%)	59 (34.5)	87 (28.4)	0.168
Alcohol, n (%)	46 (26.9)	67 (21.9)	0.218
Hypertension, n (%)	46 (26.9)	75 (24.5)	0.565
Ischemic heart disease, n (%)	6 (3.5)	7 (2.3)	0.622
Diabetes, n (%)	22 (12.9)	39 (12.7)	0.970
Hepatitis, n (%)	14 (8.2)	16 (5.2)	0.202
History of malignancy, n (%)	9 (5.3)	12 (3.9)	0.493
Incomplete intestinal obstruction, n (%)	20 (11.7)	25 (8.2)	0.206
Preoperative chemotherapy, n (%)	32 (18.7)	65 (21.2)	0.511
Preoperative radiotherapy, n (%)	21 (12.3)	44 (14.4)	0.522
Preoperative hemoglobin, (g/L, mean ± SD)	136.8 ± 18.1	136.2 ± 18.0	0.813
Preoperative albumin (g/L, mean ± SD)	43.6 ± 3.5	44.2 ± 3.7	0.075
ASA grade, n (%)			0.987
1	6 (3.5)	14 (4.6)
2	154 (90.1)	269 (87.9)
3	11 (6.4)	23 (7.5)

SD: Standard deviation; BMI: Body mass index; ASA: American Society of Anesthesiologists.

Table 2 Surgery-related variables

Variable	Intraoperative chemotherapy (+) (n = 171)	Intraoperative chemotherapy(-) (n = 306)	P-value
Approach, n (%)			0.751
Open	4 (2.3)	6 (2.0)
Laparoscopic	167 (97.7)	300 (98.0)
NOSE surgery, n (%)	3 (1.8)	18 (5.9)	0.035a
Operation time, (min, mean ± SD)	164.0 ± 54.7	172.0 ± 62.9	0.187
Consolidation suture, n (%)	27 (15.8)	37 (12.1)	0.256
Defunctioning stoma, n (%)	46 (26.9)	64 (20.9)	0.137
Estimated blood loss (mL, mean ± SD)	59.7 ± 54.4	67.1 ± 100.1	0.764
Transfusion, n (%)	4 (2.3)	14 (4.6)	0.219
Left colic artery preservation, n (%)	11 (6.4)	20 (6.5)	0.965
Transanal tube, n (%)	75 (43.9)	170 (55.6)	0.014a
Number of stapler firing, n (%)			0.007a
1 and 2	146 (85.4)	229 (74.8)
More than 2	25 (14.6)	77 (25.2)

^aP < 0.05 vs Control. SD: Standard deviation; NOSE: Natural orifice specimen extraction.

Table 3 Tumor related variables

Variable	Intraoperative chemotherapy (+) (n = 171)	Intraoperative chemotherapy(-) (n = 306)	P-value
Distance of tumor from anal verge (cm, mean ± SD)	7.9 ± 3.0	8.3 ± 2.9	0.092
Tumor location, n (%)			0.621
Above peritoneal reflection	121 (70.8)	223 (72.9)
Below peritoneal reflection	50 (29.2)	83 (27.1)
Pathological T stage, n (%)			0.865
T1, T2, and no tumor residual after preoperative therapy	25 (14.6)	43 (14.1)
T3 and T4	146 (85.4)	263 (85.9)
Pathological N stage, n (%)			0.337
N0 and no tumor residual after preoperative therapy	81 (47.4)	131 (42.8)
N1 and N2	90 (52.6)	175 (57.2)
TNM stage, n (%)			0.374
No tumor residual after preoperative therapy	3 (1.8)	8 (2.6)
I	8 (4.7)	11 (3.6)
II	70 (40.9)	112 (36.6)
III	90 (52.6)	175 (57.2)
Degree of differentiation, n (%)			0.628
Low and low-middle grades	58 (30.2)	94 (30.8)
Middle, high-middle, and high grades and no tumor residual after therapy	134 (69.8)	211 (69.2)

SD: Standard deviation.

Table 4 Incidence of anastomotic leakage

Variable	Intraoperative chemotherapy (+) (n = 171)	Intraoperative chemotherapy(-) (n = 306)	P-value
AL patients	13 (7.6)	5 (1.6)	0.001a
Grade, n (%)			0.044a
A	0	0
B	1 (0.6)	3 (1.0)
C	12 (7.0)	2 (0.7)
Occurrence time of AL			0.278
Early AL	13 (7.6)	4 (1.3)
Delayed AL	0	1 (0.3)

^aP < 0.05 vs Control. AL: Anastomotic leakage.

Table 5 Multivariate logistic regression analysis

Variable	P-value	OR	95%CI
Intraoperative intraperitoneal chemotherapy	0.002	5.386	1.808-16.042
Gender	0.077	3.235	0.882-11.859
Diabetes	0.985	1.015	0.213-4.843
Incomplete intestinal obstruction	0.752	1.261	0.301-5.287
Distance of tumor from anal verge	0.869	0.985	0.824-1.178
NOSE surgery	0.388	2.696	0.283-25.675
Consolidation suture	0.319	0.340	0.041-2.835
Defunctioning stoma	0.157	0.312	0.062-1.565
Transanal tube	0.518	0.708	0.248-2.019
Number of stapler firing	0.733	0.811	0.244-2.698

OR: Odds ratio; CI: Confidence interval; NOSE: Natural orifice specimen extraction.

Table 6 Stratification analysis

Variable	P-value	OR	95%CI	Woolf homogeneity test
Gender				P = 0.805
Male	0.002	5.276	1.637-17.000
Female	0.589	3.767	0.335-42.393
Overall	0.003	4.962	1.733-14.206
Diabetes				P = 0.441
Yes	1.000	1.810	0.108-30.436
No	0.001	5.759	1.823-18.193
Overall	0.002	4.941	1.732-14.093
Incomplete intestinal obstruction				P = 0.305
Yes	0.161	2.471	1.712-3.565
No	0.009	3.915	1.313-11.673
Overall	0.003	4.936	1.714-14.217
Tumor location				P = 0.964
Above peritoneal reflection	0.009	4.932	1.513-16.081
Below peritoneal reflection	0.296	5.234	0.529-51.758
Overall	0.002	4.997	1.748-14.286
NOSE surgery				P = 0.209
Yes	0.143	10.000	2.685-37.239
No	0.003	4.354	1.506-12.585
Overall	0.002	4.855	1.727-13.649
Consolidation suture				P = 0.588
Yes	0.422	2.423	1.805-3.253
No	0.002	4.800	1.656-13.910
Overall	0.002	5.162	1.797-14.829
Defunctioning stoma				P = 0.302
Yes	1.000	1.400	0.085-22.978
No	<0.001	6.319	1.994-20.026
Overall	0.002	5.092	1.793-14.461
Transanal tube				P = 0.468
Yes	0.259	3.136	0.684-14.375
No	0.013	6.931	1.463-32.844
Overall	0.004	4.894	1.682-14.241
Number of stapler firings				P = 0.480
1 and 2	0.011	4.136	1.272-13.446
More than 2	0.045	10.364	1.026-104.656
Overall	0.002	4.942	1.733-14.096

OR: Odds ratio; CI: Confidence interval; NOSE: Natural orifice specimen extraction.