Prognostic Significance of Primary Tumor Surgery in Adenoid Cystic Carcinoma Patients With Distant Metastases at Diagnosis: A Population-Based Database Analysis in Head and Neck Region.

Adenoid cystic carcinoma (ACC) is an aggressive cancer that often leads to poor prognosis, especially when it has metastasized. The prognostic significance of primary tumor surgery (PTS) for ACC with distant metastasis (DM) at the time of diagnosis has not been extensively studied. Using data from the surveillance, epidemiology, and end results (SEER) database from 2010 to 2019, we identified patients with ACC in head and neck region and synchronous DM. We evaluated the effect of PTS on different patterns of metastasis using Kaplan-Meier analysis, log-rank tests, and multivariate Cox regression analysis to assess the therapeutic benefit of PTS in the overall cohort and various subgroups. Of the 192 identified patients with synchronous metastatic ACC of head and neck, 91 (47.4%) underwent PTS. Patients who received PTS had significantly better survival than nonsurgical patients (median overall survival: 19 vs 43 months, = .006). Cox regression analysis also showed that PTS was associated with improved survival (HR = .46, 95% CI: 0.42-0.88; = .028). In sub-analyses, except for patients with liver metastases [overall survival (OS), = .107, cancer-specific survival (CSS), = .153], PTS consistently conferred significant survival benefits in patients with bone metastases (OS, = .041, CSS, = .065) and lung metastases (OS, = .016, CSS, = .027). PTS also led to better survival in patients who did not receive radiotherapy (median OS: 13 vs 52 months, = .007). Our study suggests that PTS in metastatic ACC patients of head and neck improved overall and CSS, particularly in those with bone or lung metastases and those who did not receive radiotherapy. However, further prospective studies are needed to confirm these findings, and the indications for PTS in metastatic ACC should be carefully evaluated by a multidisciplinary board.