Long-Term Obesity Is Linked With Poorer Pancreatic Cancer Survival
Although multiple studies have shown that high body mass index (BMI) is associated with an increased risk of developing pancreatic cancer, few studies have evaluated the impact of BMI on survival and none have used prospectively collected data on BMI. Now a large prospective study by Brian M. Wolpin, MD, MPH, Assistant Professor of Medicine at Dana-Farber Cancer Institute and Harvard Medical School, and colleagues has found that patients with a BMI in the obese range live on average 2 to 3 months less following their diagnosis compared with healthy-weight patients. The study is published in the Journal of Clinical Oncology.
The researchers analyzed survival by prediagnostic BMI assessed in 1986 among 902 participants from two large prospective cohorts—The Nurses’ Health Study and the Health Professionals Follow-up Study—diagnosed with pancreatic cancer between 1988 and 2010. Their findings show that the median length of survival after diagnosis was 5 months. On average, healthy-weight patients (BMI < 25 kg/m2) lived 2 to 3 months longer than obese patients (BMI ≥ 35 kg/m2).
The association between higher prediagnostic BMI and shorter survival continued after adjusting for differences in age, gender, race/ethnicity, smoking status, and disease stage. The study also found that obese patients were more likely to be diagnosed with advanced disease: 72% of obese patients had metastatic disease at diagnosis compared with 59% of healthy-weight patients.
In addition, the association between BMI and survival was strongest among the 202 patients with high BMI measured 18 to 20 years before diagnosis, “suggesting the importance of chronic exposure to elevated BMI in the association with survival,” wrote the researchers.
“While previous retrospective studies suggested a link between obesity and pancreatic cancer survival, the prospective nature of this study makes the findings more reliable,” said Smitha S. Krishnamurthi, MD, ASCO Cancer Communications Committee member and gastrointestinal cancers expert.
Determining Treatment Effectiveness
The study data also suggests further avenues of research on the link between obesity and cancer, for example, whether the same changes that promote tumor development in obese people also affect tumor aggressiveness. Such research might reveal whether tumors that develop in obese people respond differently to treatments than tumors that develop in healthy-weight people.
The study authors reported no potential conflicts of interest.
Funding for this research was supported in part by a 2009 Conquer Cancer Foundation of ASCO Career Development Award to Dr. Wolpin.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
