HealthDay News — For patients with pancreatic cancer, those who were obese prediagnosis were more than twice as likely to die over an 18- to 20-year period than healthy-weight patients, researchers found.
Having a BMI of 35 or greater in the 18 to 20 years prediagnosis was associated with a 2.31-fold increased risk for death in patients with pancreatic cancer (95% CI 1.48-3.61, P<0.001) compared with having a BMI less than 25, Brian Wolpin, MD, MPH of the Dana-Faber Cancer Institute in Boston, Mass., and colleagues reported in the Journal of Clinical Oncology.
More advanced-stage disease was also more prevalent among those with higher prediagnositic BMI — 72.5% of obese patients had metastatic disease versus 59.4% of healthy-weight patients (P=0.02), they found.
A number of dietary factors have previously been associated with pancreatic cancer risk, including soft drink, bacon and sausage and heavy alcohol consumption. To analyzed the association between prediagnostic BMI and cancer survival, Wolpin and colleagues examined data from 902 pancreatic cancer patients who participated in two large prospective cohort studies, the Nurses’ Health Study and the Health Professionals Follow-Up Study.
They used prediagnostic BMI — the participant’s BMI as reported at baseline in each study — due to weight loss that can occur with subclinical or newly diagnosed pancreatic cancer. The researchers also analyzed data on age, race, smoking status, multivitamin use, weekly hours of physical activity, alcohol intake, energy intake and history of diabetes.
Data on date and stage of cancer diagnosis, as well as whether the disease local and amendable to surgical resection, locally advanced and not resectable without distant metastases, distant metastatic disease or an unknown stage was also obtained from medical records.
Mean participant age at baseline was 57.8 years, median time between baseline BMI and pancreatic cancer diagnosis was 14.7 years, mean baseline BMI was 25.9. Overall 36% of participants were considered overweight, whereas 15% were obese.
A total of 65% of participants had metastatic disease, 19.3% had localized disease and 15.3% had locally advanced disease.
Risk of death was significantly increased for patients with BMI ≥35 kg/m² versus those with BMI of less than 25 kg/m² after adjusting for age, sex, cohort enrollment, race, smoking status and time period of diagnosis (hazard ratio, 1.53; 95% CI: 1.11-2.09). With longer lag times between reported BMI and cancer diagnosis, the correlation of BMI with survival was stronger.
Among patients with BMI collected 18 to 20 years before diagnosis, hazard ratio for death was 2.31 comparing obese with healthy-weight patients. The correlation was stronger among never-smokers (HR, 1.61; P trend=0.002) than among ever-smokers (HR, 1.36; P trend = 0.63).
There was a correlation between higher prediagnostic BMI with more advanced stage at diagnosis — 72.5% and 59.4%, respectively, of obese and healthy-weight patients presented with metastatic disease.
“These data emphasize the link between chronic alterations in systemic metabolism and pancreatic cancer survival and suggest obesity-related metabolic pathways for possible therapeutic intervention in patients with pancreatic adenocarcinoma,” the researchers concluded.