Parathyroid Carcinoma: An Update on Treatment Outcomes and Prognostic Factors from the National Cancer Data Base (NCDB).

BACKGROUND: Parathyroid carcinoma is a rare disease. Conflicting results on prognostic factors and extent of surgical resection for patients with parathyroid carcinoma have been made based on small sample sizes. A large, robust dataset is needed to help address some of the controversies.

METHODS: A retrospective review of patients with parathyroid carcinoma in the National Cancer Data Base from 1985 to 2006 was performed. Characteristics of the cohort and type of treatment were evaluated. Prognostic factors were assessed with Cox proportional hazards regression models and 5- and 10-year OS rates were determined.

RESULTS: There were 733 evaluable patients with a mean age of 56.1 ± 15.3 years (median 57, range 15-89) and mean tumor size of 29.6 ± 18.4 mm (median 25.0 mm, range 10.0-150.0). Tumor size, age at diagnosis, male sex, positive nodal status, and complete tumor resection had hazard ratios for death of 1.02 (1.01-1.02, p < 0.0001), 1.06 (1.05-1.07, p < 0.0001), 1.67 (1.24-2.25, p = 0.0008), 1.25 (0.57-2.76, p = 0.6), and 0.42 (0.22-0.81, p = 0.01), respectively, on multivariable analysis. Patients who had removal of the parathyroid tumor with concomitant resection of adjacent organs had HR for death of 0.70 (0.35-1.41, p = 0.3). The 5- and 10-year OS rates were 82.3 and 66 % respectively.

CONCLUSIONS: Patient age, tumor size, and sex have modest effects on survival in patients with parathyroid carcinoma. A staging system with prognostic value for parathyroid carcinoma should include at least these pertinent prognostic factors.