O-093. Incidence of second primary tumors in a cohort of head and neck cancer patients in Brazil

Aims: Second primary tumors are an important issue in the follow-up of a cancer patient. About 10-20% of the patients with head and neck cancer will develop a second primary tumor during follow-up period. The objectives of this study were to analyze factors associated with the development of a second primary tumor in head and neck patients and to compare its incidence with that in the general population. Method: Patients were prospectively enrolled in three metropolitan areas as part of a case-control study. Six-hundred and five patients presenting with a previously untreated head and neck cancer were eligible and analyzed in this study. Results: Forty-seven patients (7.8%) developed a second primary cancer. The site of primary tumor was the only important factor associated with risk of a second primary: patients with lip, oral and oropharyngeal cancers had a RR of 2.56 (95% CI 1.2-5.2), compared with larynx and hypopharynx cancer patients. There were 47 second primaries in the cohort, while the expected frequency (based on general population rates) was 14.4, for a standardized incidence ratio of 3.26 (95% CI 2.4-4.3). Conclusions: Patients with lip, oral and oropharyngeal carcinomas had a higher risk of developing a second primary tumor when compared with larynx and hypopharynx cancer patients. Moreover, patients with head and neck cancer showed a higher incidence rate of second primary tumor when compared with the general population.