Pre-diagnosis consumption of preserved vegetables and prognosis of invasive oesophageal squamous cell carcinoma: a prospective cohort study in one high-risk area in China

OBJECTIVE: To investigate the prognostic effect of pre-diagnosis preserved vegetable consumption on oesophageal squamous cell carcinoma (ESCC) in Yanting County, China. METHODS: This prospective cohort study enrolled consecutive patients with ESCC. The pre-diagnosis diet consumption data were collected using a food frequency questionnaire at baseline. Preserved vegetable consumption was categorized into two groups: < 1/week and ≥1/week. Kaplan–Meier survival curve analysis with a log-rank test and a Cox proportional hazard regression model analysis were undertaken to compare the two consumption groups. RESULTS: The study enrolled 185 patients (121 males and 64 females) with ESCC. Patients consuming preserved vegetables ≥1/week had a median survival time of 41 months, but patients consuming preserved vegetables <1/week did not achieve a median survival time. The adjusted hazard ratio (HR) for an intake of ≥1/week was 1.58 (95% confidence interval [CI] 1.01, 2.47). Among ‘ever smokers’, the HR increased to 2.04 (95% CI 1.10, 3.77) and among ‘ever alcohol drinkers’, the HR increased to 2.50 (95% CI 1.33, 4.73). Among ‘never smokers’ or ‘never alcohol drinkers’, no significant association was observed. CONCLUSION: A high consumption of preserved vegetables was associated with a poorer prognosis among patients with ESCC.