['We have analyzed the risk factors and the impact of external beam radiotherapy (EBRT) in reducing the locoregional recurrence of parathyroid carcinoma (PTC).', 'Various parameters such as clinical presentation, intraoperative findings, surgical methods, and usage of parafibromin were analyzed. Selected endpoints were locoregional progression-free survival and overall survival.', 'Three patients had local recurrence. Two of them received EBRT after the first recurrence but continued to have local recurrence. One patient was lost to follow-up. Six patients with EBRT remain asymptomatic with a locoregional progression-free survival and overall survival of 42 months. The presence of a palpable nodule in the neck, serum calcium >14 mg/dL, and intraoperative substrap adhesion (OR=9.3, 95% confidence interval, 1.76-56.1; P<0.05) should raise suspicion. Four of 5 patients showed a predominantly negative staining with parafibromin.'] Is high index of clinical suspicion with optimal surgical techniques and adjuvant radiotherapy critical to reduce locoregional disease progression in parathyroid carcinoma?