New primary lung cancers after a head and neck cancer: The impact of radiation therapy and latency period on risk.

Abstract

10015 Background: Patients with head and neck cancer (HNC) have an increased risk of developing a new primary lung cancer (NPLC). Our objective was to assess the critical latency period after HNC when the risk for a NPLC was highest and to see if radiation therapy (XRT) had an impact on this risk. Methods: This was a population based study of patients with HNC in the Surveillance, Epidemiology, and End Results (SEER) database. The risk of NPLC was calculated using standardized incidence ratios (SIR) and from this, the number needed to screen (NNS) was extrapolated. The cohort was separated by delivery of XRT and latency period of the NPLC. Results: There were a total of 4,209 NPLC from the cohort of 85,154 HNC patients. The SIR, NNS, observed/expected number of NPLC for both the no XRT and XRT groups are shown in table 1. As compared to the no XRT group, the XRT group had higher SIR and lower NNS values across all latency periods. The highest SIR for both the no XRT and XRT groups came between 1 and 3 years. Conclusions: In patients with HNC, the risk of developing a NPLC is associated with receiving XRT. This risk is highest within 10 years of the initial HNC diagnosis. The NNS was especially low for the XRT group, less than 100 for most latency periods. Since low dose computed tomography scans for lung cancer screening in smokers has a NNS of 217, screening for these patients should be considered, especially within 10 years of the primary HNC diagnosis. This may contribute to better survivorship care in these patients. [Table: see text]