What is the recommended treatment for a patient with parathyroid adenoma?

Treatment of Parathyroid Adenoma

Surgical excision of the abnormally functioning parathyroid tissue is the definitive treatment for parathyroid adenoma and is typically indicated even when asymptomatic, given the potential negative effects of long-term hypercalcemia. 1

Surgical Approach Selection

The choice between two curative operative strategies depends on preoperative imaging findings and clinical context:

Minimally Invasive Parathyroidectomy (MIP)

• MIP is the preferred approach for patients with a single parathyroid adenoma confirmed by concordant preoperative imaging (occurs in approximately 80% of primary hyperparathyroidism cases). 1
• This unilateral operation with limited dissection targets only the affected gland and offers significant advantages:
  • Shorter operating times (mean 23-47 minutes in specialized centers) 2, 3
  • Faster recovery 1
  • Decreased perioperative costs 1
  • Lower morbidity 4
• MIP requires confident and precise preoperative localization of a single parathyroid adenoma to guide the surgical approach. 1
• Intraoperative PTH monitoring must be used to confirm removal of the hyperfunctioning gland. 1

Bilateral Neck Exploration (BNE)

• BNE remains the necessary surgical method in specific situations: 1
  • Discordant or nonlocalizing preoperative imaging
  • High suspicion for multigland disease (MGD), which affects approximately 15-20% of patients 1
  • Parathyroid carcinoma (rare, <1% of cases) 1
• During BNE, all parathyroid glands are identified and examined by the surgeon, who resects the diseased glands. 1

Preoperative Imaging Requirements

Preoperative imaging is essential for surgical planning but has no utility in confirming or excluding the diagnosis of primary hyperparathyroidism (diagnosis is made biochemically with serum calcium and PTH). 1

Recommended Imaging Studies

• The combination of ultrasound and 99mTc-sestamibi scintigraphy with SPECT/CT (parathyroid scan) is highly sensitive for parathyroid adenoma localization. 1
• Adding ultrasound to sestamibi scan increases accuracy of adenoma detection to 83% (compared to 74% for sestamibi alone or 61% for ultrasound alone). 4
• 4-D parathyroid CT (multiphase CT neck without and with IV contrast) is an alternative imaging modality with reported sensitivity of 79-92% for single-gland disease. 1

Critical Imaging Considerations

• Preoperative imaging is absolutely essential in the reoperative setting (persistent or recurrent hyperparathyroidism) to localize target lesions and identify postoperative changes from previous explorations. 1
• Parathyroid reoperations have lower cure rates and higher complication rates than first-time surgery. 1

Intraoperative Monitoring

Intraoperative quick PTH (QPTH) measurement is strongly recommended during MIP to confirm complete removal of hyperfunctioning parathyroid tissue. 5, 6

• PTH levels should be assessed no earlier than 12 hours after dosing if using calcimimetics preoperatively. 7
• Persistence of elevated QPTH after removal of the visualized adenoma suggests occult hyperfunctioning tissue and may require conversion to BNE. 5

Special Populations and Situations

Ectopic Parathyroid Adenomas

• Radio-guided surgery using intraoperative gamma probe is particularly useful for detecting adenomas in ectopic locations: 5, 6, 3
  • Upper mediastinum
  • Carotid bifurcation
  • Deep paratracheal/paraesophageal space
  • Intrathymic locations
• Very low doses of Tc-99m MIBI (1-37 MBq) are adequate for successful radio-guided surgery. 6, 3

Patients with Previous Neck Surgery

• MIP can be successfully performed in patients who have undergone previous parathyroid or thyroid surgery, limiting surgical trauma at reoperation. 5, 6
• Success rates of 78-97% have been reported in this population. 5, 6

Concomitant Nodular Goiter

• The gamma probe technique is not recommended in patients with concomitant nodular goiter (except for ectopic adenomas), as it is difficult to differentiate radioactivity of the adenoma from thyroid nodules intraoperatively. 5, 6
• BNE is the preferred approach in these patients. 5

Hereditary Syndromes

• In patients with multiple endocrine neoplasia syndromes, the surgical approach may include total four-gland parathyroidectomy with autotransplantation of parathyroid tissue to the neck or forearm. 1
• Transcervical thymectomy is often performed concurrently due to increased risk of supernumerary or intrathymic parathyroid glands. 1

Medical Management (Non-Surgical Candidates Only)

Cinacalcet is indicated for treatment of hypercalcemia in adult patients with primary hyperparathyroidism for whom parathyroidectomy would be indicated on the basis of serum calcium levels, but who are unable to undergo parathyroidectomy. 7

• Starting dose: 30 mg twice daily 7
• Titrate every 2-4 weeks through sequential doses (30 mg twice daily, 60 mg twice daily, 90 mg twice daily, and 90 mg 3-4 times daily) to normalize serum calcium 7
• This is NOT first-line therapy—surgery remains the only definitive cure. 1
• Cinacalcet is contraindicated if serum calcium is below the lower limit of normal. 7

Common Pitfalls to Avoid

• Do not rely on imaging alone to diagnose hyperparathyroidism—diagnosis must be biochemical. 1
• Do not proceed with MIP if imaging is discordant or nonlocalizing—convert to BNE. 1
• Do not skip intraoperative PTH monitoring during MIP—this is essential to confirm adequate resection. 5, 6
• Monitor for hypocalcemia postoperatively, particularly in patients with severe or long-standing disease. 7

Outcomes

• Overall cure rate of 98.6% can be achieved with appropriate patient selection, preoperative localization, and intraoperative PTH monitoring. 4
• MIP success rates of 97-98.85% have been reported in appropriately selected patients. 5, 6, 3
• Conversion to BNE is required in only 1.4-4.3% of cases planned for MIP. 5, 4