Parathyroid Cancer Treatment (PDQ®): Treatment - Health Professional Information [NCI] - General Information About Parathyroid Cancer
Parathyroid Cancer Treatment (PDQ®): Treatment - Health Professional Information [NCI] Guide
- General Information About Parathyroid Cancer
- Cellular Classification of Parathyroid Cancer
- Stage Information for Parathyroid Cancer
- Treatment Option Overview
- Localized Parathyroid Cancer
- Metastatic Parathyroid Cancer
- Recurrent Parathyroid Cancer
- Changes to This Summary (11 / 08 / 2013)
- About This PDQ Summary
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Approximately 40% to 60% of patients experience a postsurgical recurrence, typically in the range of 2 to 5 years after the initial resection.[11,12] In most cases, hypercalcemia precedes physical evidence of recurrent disease. The location of recurrence is typically regional, either in the tissues of the neck or in cervical lymph nodes, and accounts for approximately two thirds of recurrent cases.[13] Often, local recurrences in the neck are difficult to identify because they may be small and multifocal, and they may involve scar tissue from a previous surgical procedure. Use of ultrasonography, sestamibi-thallium scanning, and positron emission tomography may help to identify difficult-to-detect recurrent disease.[14,15,16] In older studies, distant metastases were reported to occur in 25% of patients, primarily in the lungs but also in the bone and liver.[13,17] More recent series indicate that the incidence of recurrence may be higher, possibly because of more accurate pathologic diagnoses that exclude patients with atypical adenomas.[1] Because of its low malignant potential, the morbidity and mortality associated with parathyroid cancer primarily result from the metabolic consequences of the disease and not directly from malignant growth.[9,17] In the National Cancer Database series of 286 patients, the 10-year survival rate was reported to be approximately 49%.[2] A smaller series has reported a 10-year survival rate of 77%, which might be related to improvements in supportive medical care and in the prevention of fatal hypercalcemia.[9]
Operatively, parathyroid cancers may be distinguished from adenomas by their firm, stony-hard consistency and lobulation; adenomas tend to be soft, round, or oval in shape, and of a reddish-brown color.[5] In most series, the median maximal diameter of parathyroid carcinoma is between 3.0 cm and 3.5 cm compared with approximately 1.5 cm for benign adenomas.[1] In approximately 50% of the patients, the malignant tumor is surrounded by a dense, fibrous, grayish-white capsule that infiltrates adjacent tissues.[5] Histopathologically, as with other endocrine neoplasms, the distinction between benign and malignant parathyroid tumors is difficult to make.[1,5,18] The extent to which capsular and vascular invasion appears to be unequivocally correlated with tumor recurrences and metastases makes a strong case for these findings to be considered the sole pathognomonic markers of malignancy.[18,19]