MA03.10 Population-Based Relative Risks for Lung Cancer Based on Complete Family History of Lung Cancer

Abstract

Published risk estimates for diagnosis of lung cancer based on family history are typically focused on close relatives, rather than a more diverse or complete family history. This study provides relative risks (RR) for lung cancer based on comprehensive family history data obtained from a statewide Cancer Registry linked to a high quality genealogy data resource. Risk estimates presented avoid common recall, recruitment, ascertainment biases, and are based on an individual’s (proband’s) lung cancer family history constellation (pattern of lung cancer affected relatives). A population-based genealogical resource linked to a statewide electronic SEER cancer registry estimated relative risk (RR) for lung cancer for an individual based upon their lung cancer family history. Family history data available for a proband included degree of relationship (first to third-degree), paternal or maternal family lung cancer history, number of lung cancer affected relatives and age at diagnosis of affected relatives. Over 1.3M probands probands with specific constellations of lung cancer were analyzed. To estimate RRs, the observed number of lung cancer cases among probands with a specific family history constellation was compared to the expected number using internal cohort-specific rates. 5,048 lung cancer cases were identified. Significantly elevated RR was observed for any number of lung-cancer-affected relatives among first-, second-, or third-degree relatives. RRs for lung cancer were significantly elevated for each additional lung cancer first-degree relative (FDR) ranging from RR=2.57 (2.39, 2.76) for >= 1 FDR to RR=4.24 (1.56, 9.23) for ≥3 FDRs affected. In an absence of FDR family history, increased risk for lung cancer was significant for increasing numbers of affected second-degree relatives (SDR) ranging from 1.41 (1.30, 1.52) for ≥ 1 SDR to 4.76(1.55, 11.11) for ≥ 4 SDRs. This was also seen in the absense of FDRs and SDRs for affected third-degree relatives (TDR) ranging from 1.18 (1.11, 1.24) for ≥1 affected TDR to 1.55 (1.03, 2.24) for ≥ 4 affected TDRs. RRs were significantly increased with earlier age at diagnosis of a first degree relative, and equivalent risks for maternal compared to paternal history were observed. This study provides unbiased, population-based estimates of lung cancer risk based on a proband’s complete family history that can be 2-5+ times increased. Estimates of RR for lung cancer based on family history are arguably very relevant clinically. The constellation RR estimates presented could serve in individual decision making to direct resource utilization, and could be pivotal in decision making for screening, treatment, and post treatment surveillance.