Incidence of vestibular schwannomas

Objective: To determine the incidence of vestibular schwannoma (VS) in Denm ark in a period of 19 1/2 years. Study Design: Retrospective review of pros pective registered data on all patients with VS operated on by the translab yrinthine, lateral suboccipital, or middle cranial fossa approach, as well as patients who were allocated to the "wait-and-scan" group. Methods: Chart s were reviewed and tabulated for age, extrameatal tumor extension, and dat e of diagnosis. The available data were divided into three periods: June 19 76 to June 1983, July 1983 to June 1990, and July 1990 to December 1995, Re sults: The number of newly diagnosed tumors in the first period was 278, co rresponding to an incidence of 7.8 tumors/million population per year in th e second period 337, corresponding to an incidence of 9.4 tumors/million po pulation per year; and in the third period 355, corresponding to an inciden ce of 12.4 tumors/million population per year, A significant increase in in cidence of the newly diagnosed intracanalicular tumors in the second and th ird periods was observed, Conclusion: The increase in incidence of VS can p robably be explained by the awareness among otolaryngologists of the diagno sis of VS and better access to computed tomography and magnetic resonance i maging scans. The observed increase in the diagnosis of the small and intra meatal tumor creates a clinical dilemma, whether to operate on tumors in th is early stage or to allocate patients to the wait-and-scan group. This pro blem will still be relevant in the upcoming years, since the incidence of i ntrameatal and small VS is expected to increase.