Is the Volume of the Parathyroid Gland a Predictor of Maxacalcitol Response in Advanced Secondary Hyperparathyroidism?

Abstract

We evaluated the relationship between the volume of parathyroid glands estimated by ultrasonography (US) and response of 22-oxa calcitriol (Maxacalcitol, OCT) in patients with secondary hyperparathyroidism (2HPT) to evaluate whether the volume can be a predictor of the OCT response. Eleven institutes participated in this study. Ninety-four patients with advanced 2HPT were enrolled. The volume of the parathyroid glands were estimated by US before and 6 months after OCT treatment. The response of OCT treatment was classified into three groups (Group A: i-PTH < 300 pg/mL; Group B: 300 pg/mL < or = i-PTH < 500 pg/mL; Group C: i-PTH > or = 500 pg/mL). Forty-eight patients were in Group A, 28 patients in Group B, and 18 patients in Group C. The PTH levels at the beginning and 6 months were 458.3-199.1 pg/mL (P < 0.0001) in Group A, 524.6-403.2 pg/mL (P = 0.007) in Group B and 736.7-613.6 pg/mL (ns) in Group C, respectively. The volume of the largest gland in Group B was significantly larger than that in Group A (96.2 vs. 343.2 mm3: P < 0.001). Clinical factors affecting response of OCT was evaluated by logistic regression analysis and only the volume of the largest gland was a significant factor. In the patients whose volume was less than 300 mm3, the OCT response was significantly effective. We conclude that the glandular volume of the largest parathyroid gland estimated by US can be a useful factor to predict the OCT response in patients with moderate or severe renal HPT.

Surgical Treatment of Secondary Hyperparathyroidism due to Chronic Kidney Disease

“…The conclusion drawn was that the volume of the largest gland as estimated by US could be a useful predictor of the response to OCT in patients with moderate or severe 2HPT. In patients whose glandular volume was less than 300 mm 3 , the OCT was significantly more effective compared with that in patients whose volume was more than 300 mm 3 (19). These results indicated that when a patient has at least one nodular gland, 2HPT may be resistant to medical treatment, including OCT. Volume of parathyroid gland estimated by ultrasonograpy By US it is possible to detect swollen parathyroid glands and measure three dimensions, and to estimate the volume of glands by using the formula (a*b*c* /6) (a,b,c: dimensions of the gland) (20).…”

Cinacalcet Effectively Reduces Parathyroid Hormone Secretion and Gland Volume Regardless of Pretreatment Gland Size in Patients with Secondary Hyperparathyroidism

“…Moreover, the response to vitamin D sterols is substantially reduced once parathyroid hyperplasia has progressed to the advanced nodular form, presumably because of the reduced expression of calcium-sensing receptors (CaSR) and vitamin D receptors (VDR) (6 -10). Several clinical studies suggest that parathyroid gland volume in excess of 500 mm 3 , as evaluated by ultrasonography, appears to be a useful indicator of responsiveness to vitamin D therapy (11)(12)(13). This concept is supported by the observation that surgically removed parathyroid glands weighing Ͼ500 mg usually exhibit nodular formations (3).…”

“…It is well known that, in patients with SHPT, the presence of parathyroid enlargement is a major determinant of response to treatment with vitamin D sterols (11)(12)(13). This finding is attributed to the observation that most of the enlarged glands removed from severe SHPT patients exhibit a nodular pattern of hyperplasia and decreased VDR expression (6,9,10), which could render the parathyroid glands less responsive to the biologic actions of vitamin D. In contrast, the present study showed that treatment with cinacalcet, an allosteric activator of the CaSR, is effective in suppressing PTH secretion even in patients with enlarged glands, in which the expression of CaSR is likely to be markedly decreased (7)(8)(9).…”

Histology and immunohistochemistry of the parathyroid glands in renal secondary hyperparathyroidism refractory to vitamin D or cinacalcet therapy

“…The failure of medical therapy is primarily due to progressive downregulation (8, 9, 10) of both calcium-sensing receptors (CaSR) and vitamin D receptors (VDR) (4,11,12,13). Actually, it is widely acknowledged that the PTG volume (maximum diameter O10 mm or volume O500 mm 3 ) negatively influences the response to calcitriol or vitamin D analog treatment (14,15). In these cases, parathyroidectomy (PTx) may be indicated (16).…”