Pancreatic Cancer Risk Linked to Number of First-Degree Relatives Who Are Affected by Cancer

The risk of developing pancreatic cancer rises with an increasing number of first-degree relatives with pancreatic or other cancer in a dose-response manner, according to a study presented at the 2018 AACR Pancreatic Cancer: Advances in Science and Clinical Care conference in Boston, Massachusetts.¹

Previous studies have suggested that first-degree relatives of patients with pancreatic cancer have a 2-fold increase in risk for developing the disease, but the effect on the risk of developing pancreatic cancer if more than 1 first-degree relative has cancer is unknown. The aim of this study was to evaluate the risk of individuals who have more than 1 first-degree relative with pancreatic cancer or some other malignancy.

The study included 721 offspring who were deemed at risk of developing pancreatic cancer and 223 kindreds, defined as affected trios — in which both parents have pancreatic cancer and/or another cancer type plus 1 offspring with pancreatic cancer. Patients whose parents both had cancer were identified using an unbiased ascertainment approach, and all patients prospectively provided detailed histories between 2000 to 2017. The Surveillance, Epidemiology, and End Results Program data were used as a referent for the general population.

The entire cohort demonstrated a significantly increased risk of developing pancreatic cancer compared with the general population (standardized incidence ratio [SIR], 3.33; 95% CI, 1.94-5.34). 

There was a dose-response relationship for risk with an increasing number of first-degree relatives with pancreatic cancer. Pancreatic cancer present in only 1 offspring resulted in an SIR of 2.72 (95% CI, 1.35-4.86), whereas when 1 parent and 1 offspring had pancreatic cancer, the SIR was 4.07 (95% CI, 1.09-10.42), and when 2 parents and 1 offspring had the disease, the SIR was 30.01 (95% CI, 3.37-108).

The authors concluded that “[pancreatic cancer] risks to offspring are 2.7- to 30-fold higher in this setting compared to the general population.” They predicted that “these results will inform genetic counseling for pancreatic cancer risk.”

Reference

1. Petersen G, Chaffee KG, Stevens MA, Toledo-Hernandez A, Fagan SE. Pancreatic cancer risk in offspring when both parents have cancer. Presented at: AACR Pancreatic Cancer: Advances in Science and Clinical Care; September 21-24, 2018; Boston, Massachusetts: Abstract A030.