Patterns and Predictors of Cervical Lymph Node Metastasis in Parathyroid Carcinoma.

BACKGROUND

Parathyroid carcinoma (PC) is a rare endocrine malignancy with poor outcomes. Over 60% of PC patients experience repeated disease recurrence or metastasis. The significance of cervical lymph node dissection (LND) for PC remains inconclusive.

METHODS

PC patients diagnosed at Peking Union Medical College Hospital between 1992 and 2021 were reviewed retrospectively. Clinical data, initial tumor histological staging, parafibromin histochemical staining results, Ki67 index, gene mutation status and outcome information were collected systemically. The risk factors for recurrence and lymph node or distant metastasis were explored.

RESULTS

Sixty-eight PC patients receiving LND were enrolled. Cervical lymph node metastasis was identified in 19.4% of patients at initial surgery and 25.0% of patients including reoperations for recurrences. The independent risk factor for PC recurrence was a Ki67 index ≥ 5% (HR4.41, 95% confidence interval (CI)1.30-14.95, = 0.017). Distant metastasis was an independent prognostic factor for PC patient overall survival (HR 5.44, 95% CI 1.66-17.82, = 0.005). High-risk Schulte staging ( = 0.021) and abnormalities ( = 0.012) were risk factors for cervical lymph node metastasis.

CONCLUSION

Most PCs were slow-growing, but lymph node metastasis was not rare. For patients planning to undergo remedial surgery after previous local resection of PC, central LND is suggested for tumors with high-risk Schulte staging or abnormalities.