Objective To investigate the prognostic value of gastroepiploic lymph node (GLN) metastasis in transverse colon cancer.

Methods The propensity score matching and retrospective cohort study was conducted. The clinicopathological data of 371 patients with transverse colon cancer who were admitted to Fujian Medical University Union Hospital from November 2010 to November 2017 were collected. There were 202 males and 169 females, aged from 21 to 92 years, with a median age of 58 years. Patients were performed complete mesocolic excision combined with GLN dissection by one group of surgeons. Of the 371 patients with transverse colon cancer, 15 cases had positive GLN metastasis (GLN+), and 356 cases had negative GLN metastasis (GLN-). Observation indicators: (1) the propensity score matching conditions and comparison of baseline data between GLN- patients and GLN+patients with transverse colon cancer after propensity score matching; (2) follow-up and survival of GLN- patients and GLN+patients with transverse colon cancer; (3) influencing factors for prognosis of patients with transverse colon cancer. Patients were followed up by outpatient examination or telephone interview to detect tumor metastasis and survival. Follow‑up was conducted once every 3 months within postoperative 2 years, once every 6 months within postoperative 2-5 years and once a year thereafter up to January 2020. The propensity score matching was conducted by 1∶4 matching using the nearest neighbor method. Measurement data with skewed distribution were described as M (range), and comparison between groups was analyzed using the rank sum test. Count data were represented as absolute numbers, and comparison between groups was analyzed using the chi‑square test or Fisher exact probability. The Kaplan‑Meier method was used to calculate survival rates and draw survival curves, and Log‑rank test was used for survival analysis. Univariate and multivariate analyses were performed using the COX proportional hazard regression model. The variables with P<0.10 in the univariate analysis were included for multivariate analysis.

Results (1) The propensity score matching conditions and comparison of baseline data between GLN- patients and GLN+ patients with transverse colon cancer after propensity score matching: 55 of 371 patients had successful matching, including 44 GLN- patients and 11 GLN+ patients. Before propensity score matching, the age, cases in stage 0 or stage 1 of M staging, preoperative carcinoembryonic antigen were 60 years(range, 24-92 years), 328, 22, 4.1 μg/L(range, 0.2-343.7 μg/L) for GLN- patients, respectively, versus 67 years(range, 21-79 years), 11, 4, 5.0 μg/L(range, 0.7-952.4 μg/L) for GLN+ patients, showing significant differences in the above indicators between the two groups (Z=-1.440, χ²=9.031, Z=-2.086, P<0.05). After propensity score matching, the above indicators were 58 years(range, 45-67 years), 40, 4, 4.0 μg/L(range, 2.0-10.0 μg/L) for GLN- patients, respectively, versus 67 years(range, 59-71 years), 9, 2, 5.0 μg/L(range, 8.0-19.0 μg/L) for GLN+ patients, showing no significant difference between the two groups (Z=-1.580, χ²=0.105, Z=-0.821, P>0.05). (2) Follow‑up and survival of GLN- patients and GLN+ patients with transverse colon cancer: GLN- patients and GLN+ patients with transverse colon cancer were followed‑up for 12-92 months and 1-70 months, with a median time of 53 months and 30 months respectively. Three cases of GLN- patients and 2 cases of GLN+patients had postoperative liver metastasis, respectively, showing no significant difference between the two groups (χ²=0.344, P>0.05). One case of GLN- patients and 3 cases of GLN+ patients had heterochronous lung metastasis, respectively, showing a significant difference between the two groups (χ²=4.870, P<0.05). The 5‑year disease progression‑free survival rates were 82.3% and 33.9% for GLN- patients and GLN+ patients, respectively, showing a significant difference between the two groups (χ²=13.366, P<0.05). (3) Influencing factors for prognosis of patients with transverse colon cancer: results of univariate analysis showed that pT staging, pN staging, M staging and GLN metastasis were related factors for prognosis of patients with transverse colon cancer (hazard ratio=1.599, 5.107, 4.511, 6.273, 95% confidence interval as 0.467-5.471, 1.867-13.971, 1.385-14.694, 2.052-19.176, P<0.05). Results of multivariate analysis showed that pN staging, M staging and GLN metastasis were independent influencing factors for prognosis of patients with transverse colon cancer (hazard ratio=6.399, 6.163, 4.024, 95% confidence interval as 2.028-20.189, 1.666-22.800, 1.177-13.752, P<0.05).

Conclusion For the patients with transverse colon cancer, GLN metastasis is associated with high postoperative heterochronous lung metastasis rate and poor prognosis. GLN metastasis is an independent prognostic factor for patients with transverse colon cancer.