Adenoid cystic carcinoma of the paranasal sinuses

Adenoid cystic carcinoma of the paranasal sinuses is a rare neoplasm whose propensity for perineural spread frequently results in positive surgical margins at the skull base. Radiation therapy (RT) may be used to treat unresectable tumors or as an adjuvant for positive surgical margins after attempted resection. A retrospective review of the experience at the University of Michigan Medical Center was undertaken to study the factors influencing survival and to compare the efficacy of RT alone versus as an adjuvant treatment to surgical resection. All patients selected for review (n = 17) had a histologically confirmed diagnosis of adenoid cystic carcinoma arising from the paranasal sinuses with an average follow-up of 6 years. The choice of treatment modality was based upon the resectability of the tumor by clinical and radiologic parameters. This was therefore not a randomized study and there was a clear bias against the radiation only group, which contained the more advanced and locally aggressive tumors. The 6-year survival for the combined surgery + RT group was 73% compared with 50% for the radiation only group (p = NS). The overall local recurrence rate was 76% and the rate of distant metastases was 18%. Of the 10 patients who underwent surgical resection eight (80%) had positive surgical margins at the skull base.