Site specific dependency of second primary cancer in early stage head and neck squamous cell carcinoma

BACKGROUND. A study was conducted to determine the site specificity of second primary cancer (SPC) following early (Stage I and II) squamous cell carcinoma of the head and neck (SCH) and its impact on prognosis. METHODS. Between 1956 and 1999, 1,639 early stage SCHs in 1,609 patients were treated by radiotherapy at the authors' institution. The risk of additional respiratory and upper digestive tract (RUDT) carcinoma and the treatment outcome were reviewed for each SCH site. Second primary RUDT carcinomas were the second most common cause of death (113 cases) after death from primary SCH carcinomas (350 cases). RESULTS. Among the 1,609 early stage SCH patients, 333 second primary cancers were documented in 258 patients, 235 (71%) of which were RUDT carcinomas. The risk of SPCs was 3.2% per year, and the risk of SPCs in the RUDT region was 2.3% per year. The risk of SPCs was almost two times higher in males (3.7% per year) than in females (2.2% per year). The highest risk of SPC was observed in the oro-hypopharynx index cancer group (8.5% per year), and the lowest risks were observed in the epipharynx group (0% per year) and the maxillary sinus group (1.4% per year). CONCLUSIONS. Different SPC risks according to the SCH site result in a different prognosis for each site of early stage SCH. Long-term follow-up care after the initial treatment for early SCH should be continued according to the site of the initial SCH.