Mutagen sensitivity and risk of second cancer in younger adults with head and neck squamous cell cancer: 15-year results.

PURPOSE: To evaluate the mutagen sensitivity phenotype on the risk of second primary cancer (SPC) in patients with head and neck squamous cell carcinoma (HNSCC), and to estimate the long-term rate of SPC and the outcome with SPC. METHODS: A survey was made regarding SPC among 124 younger (≤ 50 years) adults with HNSCC who were enrolled in a pretreatment mutagen sensitivity investigation during 1996-2006. Mutagen sensitivity was assessed by exposing lymphocytes to bleomycin in vitro and quantifying the bleomycin-induced chromatid breaks per cell (b/c). Patients were classified as hypersensitive (> 1 b/c) or not hypersensitive (≤ 1 b/c). RESULTS: Mean follow-up time for all patients was 68 months (range: 5-288 months), and the 15-year cancer-specific survival was 15%. Twenty patients (16%) developed a SPC (15-year estimated rate: 41%), and half of them was hypersensitive. The crude rate of SPC for hypersensitive (n = 65) or not hypersensitive (n = 59) patients were 15 and 17%, respectively (p = 0.4272). The 15-year estimated rate of SPC for hypersensitive and not hypersensitive patients was 36 and 48%, respectively (p = 0.3743). Gender, UICC stages, anatomical sites of index cancer did not prove to be a significant risk factor for SPC. Forty-five percent of SPC developed after the 10-year follow-up. The 3­year cancer-specific survival was 23% with SPC. CONCLUSION: According to our findings, mutagen hypersensitivity was not associated with an increased SPC risk in HNSCC patients. Patients are at a lifelong risk of developing a SPC. Survival with SPC is very poor.