Onset and prognostic features of anastomotic leakage in patients undergoing radical surgery after neoadjuvant chemoradiation for rectal cancer

Table 1 Comparison of clinical data between the incident and non-incident groups

Category	Incident group (n = 61)		Non-incident group (n = 59)		t/χ2	P value
	Cases	Percentage (%)	Cases	Percentage (%)
Sex
Male	48	78.69	31	52.54	9.115	0.003
Female	13	21.31	28	47.46
Age (years)
< 55	33	54.10	38	64.41	1.319	0.251
≥ 55	28	45.90	21	35.59
Tumor distance from anal margin (cm)
< 5	29	47.54	35	59.32	1.672	0.196
≥ 5	32	52.46	24	40.68
Interval between radiotherapy and surgery (weeks)
≥ 8	15	24.59	18	30.51	0.527	0.468
< 8	46	75.41	41	69.49
Stoma creation (preventive)
Yes	27	44.26	22	37.29	0.604	0.437
No	34	55.74	37	62.71
Hand-sewn anastomosis
Yes	18	29.51	15	25.42	0.251	0.616
No	43	70.49	44	74.58
Surgery time (minute)
≥ 180	22	36.07	11	18.64	4.566	0.033
< 180	39	63.93	48	81.36
Intraoperative bleeding (mL)
≥ 150	23	37.70	11	18.64	5.366	0.021
< 150	38	62.30	48	81.36
Pelvic radiation injury
Yes	34	55.74	15	25.42	11.408	0.001
No	27	44.26	44	74.58
Smoking history
Yes	15	24.59	11	18.64	0.625	0.429
No	46	75.41	48	81.36
Alcohol history
Yes	16	26.23	13	22.03	0.288	0.591
No	45	73.77	46	77.97
Hypertension
Yes	11	18.03	15	25.42	0.965	0.326
No	50	81.97	44	74.58
Diabetes
Yes	8	13.11	9	15.25	0.113	0.737
No	53	86.89	50	84.75
Preoperative anemia
Yes	5	8.20	8	13.56	0.893	0.345
No	56	91.80	51	86.44
Preoperative hypoalbuminemia (< 35 g/L)
Yes	6	9.84	8	13.56	0.403	0.525
No	55	90.16	51	86.44
Intraoperative blood transfusion
Yes	25	40.98	13	22.03	4.977	0.026
No	36	59.02	46	77.97
Tumor center location
Below the peritoneal reflection	15	24.59	17	28.81	0.274	0.601
Above the peritoneal reflection	46	75.41	42	71.19
Differentiation degree
Moderately to well-differentiated	52	85.25	45	76.27	1.559	0.212
Poorly differentiated or undifferentiated	9	14.75	14	23.73

Table 2 Assignments

Factor	Assignment
Sex	Male = 1, female = 0
Surgery time (minute)	≥ 180 = 1, < 180 = 0
Bleeding amount (mL)	≥ 150 = 1, < 150 = 0
Pelvic radiation injury	Yes = 1, No = 0
Intraoperative blood transfusion	Yes = 1, No = 0

Table 3 Multivariate analysis for factors influencing postoperative anastomotic leakage

Factor	B	SE	Wald	P value	OR	95%CI
						Lower	Upper
Sex	1.204	0.407	8.754	0.003	3.335	1.502	7.407
Surgery time	0.901	0.428	4.438	0.035	2.462	1.065	5.691
Bleeding amount	0.899	0.408	4.856	0.028	1.407	1.183	1.905
Pelvic radiation injury	1.307	0.395	10.956	0.001	3.694	1.704	8.008
Intraoperative blood transfusion	0.899	0.408	4.856	0.028	2.457	1.105	5.467

OR: Odds ratio.

Table 4 Analysis of clinical manifestations and prognosis of patients with postoperative anastomotic leakage

Clinical feature	Cases	Percentage (%)
ISREC classification
Grade A	30	49.18
Grade B	25	40.98
Grade C	6	9.84
Fistula location
Anterior wall	9	14.75
Posterior wall	40	65.57
Lateral wall	8	13.11
Circumferential	4	6.56
Clinical manifestation
Fever	6	9.84
Abdominal pain/bloating	7	11.48
Abnormal drainage	1	1.64
Anorectal pus discharge	16	26.23
Anorectal/coccygeal pain	18	29.51
Rectal irritation sign	11	18.03
Abnormal vaginal discharge	2	3.28
Necrosis of everted bowel	2	3.28
Number of invasive interventions (times)
< 2	49	80.33
≥ 2	12	19.67
Prognosis
Chronic sacrococcygeal fistula formation	15	24.59
Anastomotic stenosis	18	29.51
Long-term stoma	12	19.67

ISREC: Swiss Institute for Experimental Cancer Research.

Table 5 Univariate analysis of factors affecting poor prognosis in patients with postoperative anastomotic leakage

Factor	Favorable prognosis group (n = 27)		Unfavorable prognosis group (n = 34)		t/χ2	P value
	Cases	Percentage (%)	Cases	Percentage (%)
Sex
Male	22	81.48	26	76.47	0.225	0.635
Female	5	18.52	8	23.53
Age (years)
< 55	15	55.56	18	52.94	0.041	0.839
≥ 55	12	44.44	16	47.06
Tumor distance from the anus (cm)
< 5	9	33.33	23	67.65	7.105	0.008
≥ 5	18	66.67	11	32.35
Interval between radiotherapy and surgery (weeks)
≥ 8	7	25.93	8	23.53	0.047	0.829
< 8	20	74.07	26	76.47
Prophylactic stoma
Yes	12	44.44	15	44.12	0.001	0.980
No	15	55.56	19	55.88
Hand-sewn anastomosis
Yes	9	33.33	9	26.47	0.341	0.559
No	18	66.67	25	73.53
ISREC classification
Grade A	19	70.37	11	32.35	10.468	0.005
Grade B	5	18.52	20	58.82
Grade C	3	11.11	3	8.82
Fistula location
Anterior wall	4	14.81	5	14.71	7.507	0.057
Posterior wall	14	51.85	26	76.47
Lateral wall	7	25.93	1	2.94
Circumferential	2	7.41	2	5.88

ISREC: Swiss Institute for Experimental Cancer Research.

Table 6 Multivariate analysis of factors influencing poor prognosis in patients with postoperative anastomotic leakage

Factor	B	SE	Wald	P value	OR	95%CI
						Lower	Upper
Distance of Tumor from the anal verge	1.431	0.549	6.800	0.009	4.182	1.427	12.258
ISREC Classification	0.890	0.436	4.167	0.041	2.435	1.036	5.723

The assignment was as follows: The distance between the tumor and the anal margin was < 5 cm = 1, 5 cm = 0; Swiss Institute for Experimental Cancer Research grade A = 1, grade B = 2, grade C = 3. ISREC: Swiss Institute for Experimental Cancer Research; OR: Odds ratio.