Objective: To investigate the independent factors affecting the prognosis of patients after resection of esophageal cancer, and to inquire into the relationship between GSTM1, GSTT1 gene polymorphisms and esophageal cancer prognosis.
Methods: The clinical data of 273 patients with esophageal cancer were retrospectively analyzed. The patients were followed-up after their surgery, and the gene polymorphisms of GSTM1 and GSTT1 in each individual were detected by polymerase chain reaction (PCR). The clinical features along with the gene polymorphisms of GSTM1 and GSTT1 associated with the prognosis of patients were analyzed by using the method of univariate analysis and Cox proportional hazard model. The cumulative survival rate was estimated by Kaplan-Meier methods, and the survival curves were compared by using the log-rank test.
Results: The overall cumulative survival rate of first year, third year and fifth year is 94.6%, 58.5% and 17.8%, respectively. The median survival time (MST) is 38.7 months. The results of univariate analysis showed that: infiltration depth, length of tumor, the number of lymph node metastasis, the region of lymph node metastasis and the genetic polymorphism of GSTM1 and GSTT1 gene loci were associated with the survival of postoperative patients. Cox multivariate analysis further indicated that the length of tumor, the number of lymph node metastasis and the combined genotype (1) [GSTM1 (+/+) or (+/-) & GSTT1 (-/-)] were the independent prognostic factors. The length of tumor, the number of lymph node metastasis were the risk factors for the prognosis, and the combined genotype (1) had protective effect on survival when compared with reference [GSTM1 (+/+) or (+/-) & GSTT1 (+/+) or (+/-)].
Conclusion: The length of tumor, the number of lymph node metastasis were confirmed as the independent prognostic factors of esophageal carcinoma, and the null genotypes for GSTT1 (-/-) might be a protective factor for survival and GSTM1 (-/-) might be a potential negative prognostic factor in patients with esophageal cancer.
Keywords: Esophageal carcinoma; GSTM1; GSTT1; prognostic factors.