Early adulthood body mass index, cumulative smoking, and esophageal adenocarcinoma survival

Smoking and obesity are esophageal adenocarcinoma (EAC) risk factors. However, the same risk factors may also affect biological aggressiveness and cancer outcomes. Our study evaluated the combined effects of early-adulthood obesity and cumulative smoking on the EAC survival.

In two EAC cohorts, Toronto (TO; N=235) and Boston (BO; N=329), associations between early adulthood body mass index (EA-BMI), BMI at 1year prior to diagnosis (BMI-1), and smoking with overall survival (OS) were assessed using Cox proportional hazard models, adjusted for relevant covariates.

Both cohorts were predominantly Caucasian (89%), male (88%), ever-smokers (73%) with locally advanced/metastatic EAC (78%), and good ECOG performance status (90%); median packyears was 34; median EA-BMI, 24; median BMI-1, 25. No relationships with survival were found with BMI-1. For smoking and EA-BMI, TO, BO, and combined TO-BO analyses showed similar associations: smoking conferred worse OS in the combined TO-BO cohort, with adjusted hazard ratios (aHR) of 1.22 (95%CI: 1.15-1.43;p<0.0001) for each 20 pack-year increase. Likewise, EA-BMI ≥25 was associated with worse OS (EA-BMI of 25-<30, aHR=1.84,95%CI: 1.37-2.48; and EA-BMI>30, aHR=2.78, 95%CI: 1.94-3.99). Risk of death was also increased in remotely underweight patients with EA-BMI<18.5 (aHR=2.03,95%CI: 1.27-3.24), when compared to normal-EA-BMI (18≤EA-BMI<25).

Two key modifiable behaviors, elevated BMI in early adulthood and heavy cumulative smoking history are independently associated with increased mortality risk in two North American cohorts of EAC patients.