Effect of temperature on gastro-esophageal cancer outcomes: A SEER study.

467 Background: Cold stress suppresses antitumor response in animal models, leading to tumor growth . Recent studies have also shown a negative correlation between the average annual temperature (AAT) and cancer incidence. We hypothesized that esophageal cancer (EC) and gastric cancer (GC) patients living in warmer climates have improved overall (OS) and disease-specific survival (DSS) than those living in colder climates. Methods: A retrospective analysis was conducted using the Surveillance, Epidemiology, and End Results (SEER) database from 1996 to 2015. AAT at the county level was calculated based on the National Centers for Environmental Information. Cox multivariate regression models were performed to measure the association between temperature (measured continuously at diagnosis and in 5-degree increments) and OS/DSS, adjusting for variables. All associations were compared at a significance level of 0.05. The OS and DSS were summarized using Kaplan-Meier methods. All statistics were performed using SAS version 9.4 (SAS Institute Inc., Cary, NC). Results: A total of 17,408 EC patients were analyzed. The average age of the cohort was 65 years, 79% of which were male and 21% were female. Of them, 61.6% had adenocarcinoma, and 37.6% were squamous. After adjusting for covariates, patients in regions with AAT >53.5°F had an 11% improvement in OS [HR 0.89 (95% CI 0.86-0.92), p<0.0001] and 12% in DSS [HR 0.88 (95% CI 0.85-0.91), p<0.0001]. When the temperature was analyzed in 5°F increments, with each increment, there was a 3% improvement in OS [HR 0.97 (95% CI 0.96-0.98), p<0.0001] and 4% in DSS [HR 0.96 (95% CI 0.95-0.97), p<0.0001]. Subgroup analysis of squamous and adenocarcinoma showed similar results. These findings were validated in 20,553 GC patients. After adjusting for covariates, patients in regions with AAT >53.5 had a 12% improvement in OS [HR 0.88 (95% CI 0.85-0.90), p<0.0001] and 14% in DSS [HR 0.86 (95% CI 0.83-0.89), p<0.0001]. When analyzed in 5°F increments, with each increment, there was a 4% improvement in OS [HR 0.96 (95% CI 0.95-0.97), p<0.0001] and 4% in DSS [HR 0.96 (95% CI 0.95 - 0.97), p<.0001]. Conclusions: We showed for the first time that higher environmental temperatures are associated with significant improvements in OS and DSS in patients with gastro-esophageal cancer. Further confirmatory and mechanistic studies are required to implement specific interventional strategies.[Table: see text]