Salivary gland neoplasms represent 2-7 %of all head and neck neoplasms, but only approximately 0.5% of malignancies. Acinic cell carcinoma comprises 3-9 percent of all salivary gland neoplasm and up to 17 percent of salivary gland malignancies with the majority of occurring in the parotid gland. Although the overall survival for patients with acinic cell in generally favorable, this neoplasm does have the potential to recur both locoregional and distant sites. Given the rarity of this disease there have been only few reports on prognostic factors associated with alterations in survival outcomes. The goals of this study were to to identify clinicopathologic factors associated with adverse survival as to assess the impact of local, regional, and distant recurrences on survival and furthermore.

Methods: Retrospective chart review of patients seen at MD Anderson Cancer Center from January 1970 to November 2007 with the diagnosis of acinic cell carcinoma. We 155 patients identified with mean follow-up of 6.8 years (range 0.2-38 years). The mean age at presentation was 52 years old (range 11-100).

Results: In this cohort, we observed a median survival of 28.5 years (range 0.2-38 years), with 8% (13) of patients dying from their disease. Most of these deaths, 77%, were attributed to the development of distant metastases with a mean time to death of 3.8 years (range 0.73-11.2). Women (n=104) were affected twice as often as men (n=51) but appear to have a significantly improved survival (p<0.0001). Patients diagnosed before the age of 45 years had a significantly improved survival (p<0.0001) compared to their elder counterparts, independent of gender. The size of the neoplasm at initial diagnosis also carried prognostic significance with lesions >3 cm having a decreased overall survival (p=0.037). Interestingly, the presence of positive surgical margins or the addition of postoperative radiation therapy was not correlated with alterations in survival. The local, regional, and distant recurrence rates were 20%, 9%, and 19% respectively but the presence of a recurrence, independent of site, was not associated with a diminished survival. In contrast, the development of distant metastases, most frequently to the lungs, was strongly associated with death from the disease (OR: 5.5, CI:2.11 to 14.09, p=0.0004) while local and regional recurrences did not carry this association.

Conclusions: Acinic cell carcinoma is a rare neoplasm the with a generally high survival rate. In this study we have identified several factors that are associated with poorer survival outcomes that include the male gender, age >45 years old, neoplasms > 3 cm, and the development of a recurrence at a distant metastatic site. These results suggest that maximizing local and regional control for this disease can offer substantial benefit when no distant disease is detectable. Patients with adverse risk factors should be monitored closely and aggressive adjuvant therapy should be considered for distant recurrences in this subset of patients.