Oligometastatic adenoid cystic carcinoma: Correlating tumor burden and time to treatment with outcomes

Background: There is limited information on the management and outcomes of oligometastases (OM) in adenoid cystic carcinoma (ACC).

Methods: Retrospective study of 42 patients with metastatic ACC of the head and neck. Imaging studies were analyzed to identify patients with OM (1-5 lesions) at any point during follow-up.

Results: There was radiographic evidence of OM in 33/42 (79%) patients. Eighteen patients had OM when treated for metastases, with median overall survival (OS) of 36.0 versus 9.2 years for patients with polymetastases (6+ lesions, HR 0.38, 95%CI 0.14-0.89). Earlier locally ablative treatment, but not systemic treatment, of patients with OM predicted improved survival 3 years after metastasis (HR 0.15, 95%CI 0.02-0.63) and postponed systemic treatment by 80 more months (HR 0.22, 95%CI 0.07-0.71).

Conclusions: There is a considerable population of ACC patients with detectable oligometastases, and early locally ablative treatment of oligometastases may be associated with improved outcomes.