Prognosis and risk factors for early-stage adenoid cystic carcinoma of the major salivary glands

BACKGROUND: Adenoid cystic carcinoma (ACC) is characterized by slow growth, frequent local recurrences, and distant metastasis (DM). However, these findings frequently are reported in patients with advanced-stage tumors, but the outcomes of early-stage tumors are poorly defined. We sought to evaluate the risk factors for the development of DM in early-stage ACC. METHODS: We retrospectively reviewed the charts of 60 patients who were diagnosed with clinical early-stage (T1-2/N0) ACC to determine the risk factors for development of DM and survival of these patients. RESULTS: DM was detected in 12 (20%) of the patients, with a median latency of 31.5 months after diagnosis. Univariate analysis revealed that DM was associated with age ≥45 years, pathologically positive lymph nodes, extracapsular spread (ECS) from lymph nodes, high-grade histology, and solid tumor subtype. Multivariate analysis revealed solid tumor subtype and ECS to be significantly associated with DM. Disease-specific survival rates at 5 and 10 years for patients with DM were 80% and 40%, respectively, and were both 100% for patients without DM. CONCLUSION: Although the majority of patients with clinical early-stage ACC of the major salivary glands have favorable prognosis, a significant percentage of patients will develop DM. Solid tumor subtype and nodal ECS were independent predictors of DM in early-stage ACC of major salivary glands. Other clinical and pathological variables may also contribute. These subgroups had poor overall and disease-specific survival. Such patients should be observed closely for the development of DM. Systemic therapy should be considered at the time of diagnosis.