Polymorphous low-grade adenocarcinoma: A Danish national study

• The first national study on polymorphous low-grade adenocarcinoma.
• We present survival rates and an analysis of associated prognostic factors.
• The study confirms PLGA’s indolent course but with a notable amount of recurrences.
• Findings warrant complete surgical excision as the primary treatment.
• Adjuvant radiotherapy should be considered in high-risk cases.

SummaryObjectivesTo present a national series of polymorphous low-grade adenocarcinoma (PLGA) patients, including survival rates and an analysis of prognostic factors.Materials and methodsBy merging three Danish nationwide registries, 73 patients diagnosed with PLGA from 1990 to 2005 were identified. Histological slides were reviewed and data concerning demographics, tumour site, clinical stage, treatment profiles and follow-up were retrieved. Survival estimates and prognostic factors were evaluated by comparing Kaplan–Meier plots using the Mantel–Haenszel log-rank test.ResultsOf the 73 patients, 47 (64%) were female. Median age was 58 years. The most common location was the palate (73%). Median latency was five months. Recurrence was seen in 13% of patients. Overall survival (OS), disease-specific survival (DSS) and recurrence-free survival (RFS) rates after 10 years were 73%, 99% and 83%, respectively. Univariate analyses suggested that free resection margins significantly improve RFS.ConclusionPLGA usually has an excellent survival outcome even in cases of advanced stage disease and locoregional recurrence. Primary choice of treatment should be complete surgical excision. Although there is no convincing evidence for the efficacy of adjuvant radiotherapy, it should still be considered, particularly in cases of involved resection margins and advanced stage disease. Late recurrences are common and respond well to salvage therapy.