Second primary malignancy for early-stage head and neck squamous cell carcinoma by SEER17 registries

Investigating treatment modalities' association with second primary malignancy risk in early-stage head and neck squamous cell carcinoma (HNSCC).

Data of 5-year survivors of early-stage (stages I-II, seventh TNM staging manual) HNSCC from 2000 to 2020 were extracted from the Surveillance, Epidemiology, and End Results (SEER) database. Standardized incidence ratio and excess absolute risk were used to assess second primary malignancy (SPM) development externally. Relative risk was estimated to compare SPM risk within groups. Fine-Gray's model estimated cumulative incidence of second primary malignancy.

Overall, 8957 5-year survivors with early-stage HNSCC were enrolled. Patients receiving definitive radiotherapy had poorer survival than surgery patients. Surgery correlated with lower risk of second primary malignancy (RR = 0.89, 95% CI 0.80-0.99), especially for oropharyngeal squamous cell carcinoma (RR = 0.56, 95% CI 0.39-0.82). Differences in the risk of second primary malignancy among subgroups based on clinical characteristics were not significant. Treatment modalities did not significantly affect risk of second primary malignancy within each subgroup.

Surgery led to better survival and lower risk of second primary malignancy compared to definitive radiotherapy in 5-year survivors. Incidence and sites of second primary malignancy varied by primary sites, emphasizing targeted long-term surveillance's importance.