Abstract 1191: Differences in time to second primary malignancies: Development among patients with head and neck squamous cell carcinoma
Authors: Boakye Eric Adjei , Buchanan Paula , Hinyard Leslie , Osazuwa-Peters Nosayaba , Schootman Mario , Piccirillo Jay F. 
Published: August 2018

Abstract
Purpose: Second primary malignancies (SPMs) are the leading cause of death in survivors of head and neck squamous cell carcinoma (HNSCC). Patients with HNSCC are at increased risk of SPM. This is concerning since the number of survivors among these patients has been increasing. The human papillomavirus (HPV) has emerged as a distinct risk factor for oropharyngeal squamous cell carcinoma, which has different prognosis from classic tobacco/alcohol-associated HNSCC. We assessed the time to development of SPM in a large U.S. cohort of patients with an index HNSCC, comparing potentially-HPV-associated and non-HPV-associated HNSCC.
Methods: This was a population-based cohort study of 109,512 patients with HNSCC in the Surveillance, Epidemiology, and End Results registry (2000-2014). HNSCC included were for invasive squamous cell carcinoma per the International Classification of Diseases for Oncology, third edition codes. SPM was defined as the first subsequent primary cancer occurring at least 2 months after first cancer diagnosis. Time to SPM development was calculated as the date of diagnosis of SPM minus 2 months after the index diagnosis date. The main exposure was HPV-relatedness, based on whether patients' first HNSCC was potentially-HPV-associated or non-HPV-associated. Adjusted Cox proportional hazards regression model was used to evaluate the differences in the time to development of SPM and HPV-relatedness, adjusting for age at diagnosis, sex, race, marital status, year of diagnosis of first cancer, stage, grade, and treatment.
Results: Among the 109,512 patients with an index HNSCC, 12.3% developed SPM. Median time to SPM development overall was 31 months, for an index potentially-HPV-associated HNSCC patients was 32 months, and for an index non-HPV-associated HNSCC patients was 30 months. Patients diagnosed with an index non-HPV-associated HNSCC had a 36% higher risk of developing SPM (aHR=1.36; 95% CI: 1.38-2.53) compared with those with an index potentially-HPV-associated HNSCC. When sites were broken down further, compared to patients with oropharynx cancer, patients with hypopharynx (aHR=1.63; 95% CI: 1.50-1.77) had the higher risk of developing SPM, followed by oral cavity (aHR=1.40; 95% CI: 1.33-1.47), and larynx (aHR=1.27; 95% CI: 1.21-1.33) cancers. Patients had higher risk of developing SPM if they were 60-69 (aHR=2.49; 95% CI: 2.34-2.66) or ≥70 (aHR=2.82; 95% CI: 2.64-3.02) vs. 18-49 years, male (aHR=1.08; 95% CI: 1.04-1.13), black (aHR=1.23; 95% CI: 1.16-1.30) vs. white, and distant (aHR=1.15; 95% CI: 1.09-1.23) vs. localized tumor.
Conclusion: Patients with an index non-HPV-associated-HNSCC were more likely to develop SPM compared to those with potentially-HPV-associated-HNSCC. Health care professionals may consider this during follow-up of patients with HNSCC.
Citation Format: Eric Adjei Boakye, Paula Buchanan, Leslie Hinyard, Nosayaba Osazuwa-Peters, Mario Schootman, Jay F. Piccirillo. Differences in time to second primary malignancies: Development among patients with head and neck squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1191.