Beyond the initial diagnosis: Epidemiological factors associated with second primary cancers among patients with head and neck squamous cell carcinoma (a SEER-based study).

6081 Background: Patients with Head and Neck cancer squamous cell carcinoma (HNSSC) have an increased risk of developing a Second Primary Cancer (SPC). We evaluated the epidemiological factors associated with SPC among patients with Stage 1-4 HNSCC using the SEER database from 2004-2020. Methods: Stage 1-4 HNSSC cases from 2004-2020, with a minimum of six months of follow-up, were identified using SEER.Stat 8.4.2 using ICD-10 CM codes. Adjusted odd’s ratios (aOR) for developing SPC (dependent variable) and the independent variables (sex, age, race and ethnicity, site of primary cancer, and marital status) were generated using multivariate logistic regression. All the analyses were performed on SAS OnDemand. Results: 127,919 cases of HNSCC were identified from 2004-2020. Oral cavity cancer accounted for 41.2% of the cases. 18,192 (14.2%) patients developed SPC. Patients with primary hypopharynx, laryngeal, and oral cavity cancer had the highest odds of developing SPC (p< 0.0001). The most prevalent sites for developing SPC were the lung (25.0%), head and neck (24.1%), and prostate (10.6 %). Males had significantly higher odds of developing SPC than females (aOR - 1.11 (1.07, 1.5)). When compared to the NH-white population, Hispanics and NH-Asian had significantly lower odds of developing SPC (aOR - 0.72 (0.68, 0.77) and 0.72 (0.68, 0.78) respectively), while NH-Blacks had higher odds of developing SPC (aOR - 1.1(1.01,1.23)). Conclusions: Our study emphasizes the substantial risk of SPC in HNSCC patients, with oral cavity cancer as the predominant primary cancer subtype. Specific HNSCC sites show elevated SPC odds, mainly primary hypopharyngeal cancer, emphasizing the need for targeted surveillance. Demographic variations reveal gender and racial disparities in SPC susceptibility, advocating for tailored monitoring and preventive strategies in high-risk subpopulations to enhance overall cancer care and survivorship. Table: see text