Polymorphous low-grade adenocarcinoma of the head and neck: A population-based study of 460 cases.

Abstract

Polymorphous low-grade adenocarcinoma (PLGA) is a rare malignant neoplasm of the minor salivary glands. This study analyzes the demographic, clinicopathologic, incidence, and survival characteristics of head and neck PLGA (HN-PLGA). The Surveillance, Epidemiology, and End Results (SEER) database was queried for HN-PLGA cases from 2001 to 2011 (460 cases). Data analyzed included patient demographics, incidence trends, and survival outcomes. Head and neck PLGA occurred most frequently in the sixth and seventh decades of life. Mean age at diagnosis was 61.3 (± 15.0) years. There was a female predilection with a female-to-male ratio of 2.15:1. There was a predilection toward blacks among the US population, with black-to-white incidence rate ratio of 2.33:1. The most common site of HN-PLGA was the palate (57.2%), followed by the lip (7.0%). Average tumor size was 2.1 (± 1.3) cm at presentation. The majority of cases were localized at the time of presentation (70.5%), with rare distant metastasis (4.3%). The most common treatment modality was surgery alone (77.9%), followed by surgery with radiotherapy (19.5%). Elective neck dissection was performed in 5.3% of the cases. Survival analysis showed excellent 10-year disease-specific (96.4%) and relative (94.7%) survival rates. Ten-year disease-specific survival was better among those treated with surgery alone (98.0%) or surgery with adjuvant radiotherapy (90.9%) than those treated with radiotherapy alone (75.0%) (P < 0.0001). This study represents the largest cohort of HN-PLGA cases. Head and neck PLGA shows a predilection for women and blacks in the US population. It has an excellent survival outcome with surgery being the treatment of choice.