RESUMO
BACKGROUND: Parathyroid carcinoma (PC) is an uncommon disease that generally is detected postoperatively and traditionally is associated with a poor prognosis. Our purpose was to evaluate treatment outcomes, prognostic factors, and usefulness of some proposed staging systems for this disease. METHODS: A multicenter review of patients with surgically resected PC was performed, led by the Spanish Association of Surgery. All surgical units affiliated with its endocrine surgery section were invited to answer a questionnaire that collected several hospital-related, clinical, biochemical, operative, pathologic, and follow-up data. Their relationships with prognosis were assessed by both univariate and multivariate analysis, as well as the effectiveness of three staging systems for parathyroid carcinoma. RESULT: Of the 6,863 patients undergoing parathyroidectomy, 62 (0.9%) had PC. Of them, 12 (19.3%) died, in 5 cases (8%) because of disease, and 14 (22.6%) suffered recurrence, after a median follow-up of 55 months. The most predictive independent variables on tumor recurrence were intraoperative tumor rupture (hazard ratio [HR] 6.22; 95% confidence interval [CI] 1.19-32.36; P = .030); the presence of mitotic figures within tumor parenchyma cells (HR 4.76; 95% CI 1.24-18.21; P = .022); and allocation in class III according to Schulte differentiated staging classification (HR 5.23; 95% CI 1.41-19.31; P = .013). As to disease-specific survival, poor outcomes were associated with intraoperative tumor rupture (HR 58.71; 95% CI 2.39-1,439.96; P = .013) and distant recurrence (HR 38.74; 95% CI 3.44-435.62; P = .003). CONCLUSION: In addition to factors associated with tumor histopathology and stage, prognosis of PC is greatly influenced by surgeon's performance, which emphasizes the importance of preoperative diagnosis.