Original Paper

Cancer Causes & Control

, Volume 23, Issue 12, pp 1929-1937

First online:

Obesity and survival in population-based patients with pancreatic cancer in the San Francisco Bay Area

  • Zhihong GongAffiliated withDepartment of Epidemiology and Biostatistics, University of California San FranciscoDepartment of Cancer Prevention and Control, Roswell Park Cancer Institute
  • , Elizabeth A. HollyAffiliated withDepartment of Epidemiology and Biostatistics, University of California San Francisco
  • , Paige M. BracciAffiliated withDepartment of Epidemiology and Biostatistics, University of California San Francisco Email author 

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Abstract

Background

Obesity has been consistently associated with increased risk of pancreatic cancer incidence and mortality. However, studies of obesity and overall survival in patients with pancreatic cancer are notably lacking, especially in population-based studies.

Methods

Active and passive follow-up were used to determine vital status and survival for 510 pancreatic cancer patients diagnosed from 1995 to 1999 in a large population-based case–control study in the San Francisco Bay Area. Survival rates were computed using Kaplan–Meier methods. Hazard ratios (HR) and 95 % confidence intervals (CI) were estimated in multivariable Cox proportional hazards models as measures of the association between pre-diagnostic obesity and pancreatic cancer survival.

Results

An elevated hazard ratio of 1.3 (95 % CI, 0.91–1.81) was observed for obese [body mass index (BMI) ≥ 30] compared with normal range BMI (<25) patients. Associations between BMI and overall survival did not statistically significantly vary by known prognostic and risk factors (all p-interaction ≥0.18), yet elevated HRs consistently were observed for obese compared with normal BMI patients [localized disease at diagnosis (HR, 3.1), surgical resection (HR, 1.6), ever smokers (HR, 1.6), diabetics (HR, 3.3)]. Poor survival was observed among men, older patients, more recent and current smokers, whereas improved survival was observed for Asian/Pacific Islanders.

Conclusions

Our results in general provide limited support for an association between pre-diagnostic obesity and decreased survival in patients with pancreatic cancer. Patterns of reduced survival associated with obesity in some patient subgroups could be due to chance and require assessment in larger pooled studies.

Keywords

Pancreatic cancer Obesity Survival Population-based cohort