For patients with secondary hyperparathyroidism (SHPT) refractory to medication, ultrasound-guided percutaneous microwave thermoablation may be an effective option that avoids surgery, a small study suggests.
Linxue Qian, MD, and colleagues of Beijing Friendship Hospital in China, tested outpatient thermoablation on 56 hemodialysis patients with SHPT at their hospital in 2012-2013. Serum parathyroid hormone levels (sPTH) ranged from 638–2,500 pg/mL and nodule size from 0.5–3.5 cm in diameter.
Thermoablation of the parathyroid gland required clinicians to place instruments precisely alongside nodules while avoiding healthy tissue and nerves. In a 2-step procedure, the investigators first created a buffer zone wider than 1 cm between the parathyroid gland and surrounding tissue using 2% lidocaine. After they inserted the ablation needle into the parathyroideum using ultrasound guidance (Phillips IU22 ultrasound imaging platform), they ablated the target area with microwave energy of 2,450 MHz for 3–5 seconds (KY-2000 microwave therapy). They used an unusual technique of lifting the parathyroid gland away from the esophagus, tracheal groove, and surrounding tissues in an effort to protect these structures.
A total of 138 glands were ablated. Three patients experienced hoarse throat from the procedure.
Results published in Ultrasound in Medicine & Biology showed that sPTH levels were significantly lower 1 month after thermoablation than before it. For 34 patients who had a 6-month follow-up visit, sPTH levels also were lower than baseline. Patients did experience a slight rebound of PTH after the 1-month mark possibly due to residual tumor cells at the edge of ablated nodules.
The researchers wrote that the ablation technique “fails to achieve the same effect as complete tumor resection, but the symptoms of patients were mitigated, especially regarding bone pain, which was eliminated in six patients.” Itchiness and insomnia were not improved, however.
Dr Qian and colleagues concluded that ultrasound-guided percutaneous ablation therapy for SHPT is “minimally invasive and highly targetable, requires shorter ablation time and is associated with little pain.”
They further noted that patients do not require hospitalization and have fewer complications than with surgery. Treatment also can be repeated if necessary.