Clinical presentation and management of patients with primary hyperparathyroidism in Italy

PURPOSE

Evaluation of the phenotype of primary hyperparathyroidism (PHPT), adherence to International Guidelines for parathyroidectomy (PTx), and rate of surgical cure.

METHOD

From January 2014-January 2016, we performed a prospective, multicenter study in patients with newly diagnosed PHPT. Biochemical and instrumental data were collected at baseline and during 1-year follow-up.

RESULTS

Over the first year we enrolled 604 patients (age 61 ± 14 years), mostly women (83%), referred for further evaluation and treatment advice. Five hundred sixty-six patients had sporadic PHPT (93.7%, age 63 ± 13  years), the remaining 38 (6.3%, age 41 ± 17  years) had familial PHPT. The majority of patients (59%) were asymptomatic. Surgery was advised in 281 (46.5%). Follow-up data were available in 345 patients. Eighty-seven of 158 (55.1%) symptomatic patients underwent PTx. Sixty-five (53.7%) of 121 asymptomatic patients with at least one criterion for surgery underwent PTx and 56 (46.3%) were followed without surgery. Negative parathyroid imaging studies predicted a conservative approach [symptomatic PHPT: OR 18.0 (95% CI 4.2-81.0) P < 0.001; asymptomatic PHPT: OR 10.8, (95% CI 3.1-37.15) P < 0.001). PTx was also performed in 16 of 66 (25.7%) asymptomatic patients without surgical criteria. Young age, serum calcium concentration, 24 h urinary calcium, positive parathyroid imaging (either ultrasound or MIBI scan positive in 75% vs. 16.7%, P = 0.001) were predictors of parathyroid surgery. Almost all (94%) of patients were cured by PTx.

CONCLUSIONS

Italian endocrinologists do not follow guidelines for the management of PHPT. Negative parathyroid imaging studies are strong predictors of a non-surgical approach. PTx is successful in almost all patients.

The use of ultrasensitive thyroglobulin assays reduces but does not abolish the need for TSH stimulation in patients with differentiated thyroid carcinoma

Measurement of serum Tg using ultrasensitive assays is proposed to replace TSH-stimulated Tg measurement in the follow-up of differentiated thyroid cancer (DTC). Aim of our study was to verify this possibility using two ultrasensitive Tg assays. We selected 215 DTC patients with undetectable (<1 ng/ml) basal serum Tg at the time of a recombinant human TSH (rhTSH) stimulation. According to standard criteria, 173 (80.4%) patients were considered free of disease, 17 (7.9%) had documented disease and 25 (11.7%) had no evidence of disease but detectable serum rhTSH-stimulated Tg (biochemical disease). The sera of these patients were re-assayed with two commercial ultrasensitive assays and the results were compared with the clinical data. Basal Access and E-Iason Tg assays were able to distinguish patients with persistent disease or free of disease with a sensitivity of 82.3 and 82.3%, specificity of 85.5 and 86.1%, positive predictive value (PPV) of 35.8 and 36.8%, negative predictive value (NPV) of 98 and 98.6%, respectively. With both assays the addition of neck ultrasound to basal Tg increased the sensitivity and the NPV to 100% and decreased the false negative rate to 0%. In patients with detectable basal Tg without evidence of disease, serum Tg converted from detectable to undetectable in about 80% of the cases during 2-yr follow-up. Our study indicates that the combination of neck ultrasound and basal ultrasensitive Tg allows to identify all patients free of disease and can decrease the need for rhTSH stimulation in nearly 80% of the patients.

Medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) accounts for 5-8% of all thyroid cancers. MTC is mainly sporadic in nature, but an hereditary pattern [multiple endocrine neoplasia type 2 (MEN 2)] is present in 20-30% of cases, transmitted as an autosomal-dominant trait due to germline mutations of the RET proto-oncogene. About 98% of patients with MEN 2 have germline mutations in exons 5, 8, 10, 11, 13, 14, 15 or 16 of the RET gene. The primary treatment of both hereditary and sporadic forms of MTC is total thyroidectomy and removal of all neoplastic tissue present in the neck. The therapeutic option for lymph node surgery should be dictated by the results of presurgical evaluation. After total thyroidectomy, measurements of serum calcitonin (CT) and carcinoembryonic antigen are of paramount importance in the postsurgical follow-up of patients with MTC as they reflect the presence of persistent or recurrent disease. Complete remission is demonstrated by undetectable and stimulated serum CT measurement. On the contrary, if serum CT is detectable under basal conditions or becomes detectable after stimulation, the patient is probably not cured, but imaging techniques will not demonstrate any disease until serum CT approaches levels >150 pg/ml. The tumour metastasises early to both paratracheal and lateral cervical lymph nodes. Metastases outside the neck may occur in the liver, lungs, bones and, less frequently, brain and skin. Surgery is the main treatment for local and distant metastases whenever feasible. Systemic chemotherapy with dacarbazine, 5-fluorouracil and doxorubicin (alone or in combination) has shown very limited efficacy, achieving only partial responses in the range of 10-20% and of short duration. Several kinase inhibitors are currently under evaluation and preliminary results are promising. Familial cases must be identified by searching for RET proto-oncogene mutations in the proband and in family members. Carriers of the RET gene are candidates for prophylactic thyroidectomy at different ages depending on the risk associated with the specific RET mutations.

Limited value of repeat recombinant human thyrotropin (rhTSH)-stimulated thyroglobulin testing in differentiated thyroid carcinoma patients with previous negative rhTSH-stimulated thyroglobulin and undetectable basal serum thyroglobulin levels

CONTEXT

One year after initial treatment, low-risk differentiated thyroid cancer (DTC) patients undergo recombinant human (rh)TSH-stimulated serum thyroglobulin (Tg) (rhTSH-Tg) and neck ultrasound (US).

OBJECTIVE

The need for more rhTSH-Tg in these patients is controversial. We evaluated the utility of a second rhTSH-Tg in DTC patients 2-3 yr after their first evaluation.

RESULTS

At the first rhTSH-Tg, basal and stimulated serum Tg was undetectable in 68 of 85 patients. Neck US was unremarkable in all but one, who had evidence of lymph node disease. Seventeen of 85 patients had undetectable serum Tg that became positive after rhTSH, with negative imaging in 10 and evidence of disease in seven. Patients with no evidence of disease were reevaluated 2-3 yr later (second rhTSH-Tg). In patients in which the first stimulated Tg was undetectable, all had undetectable basal serum Tg, which remained undetectable after rhTSH in 66 of 67 patients (98.5%) and became detectable in one (1.5%) (positive neck US). In the 10 patients with detectable stimulated Tg in the first test, basal serum Tg and US were negative at the second test, but rhTSH-Tg became detectable in six. Compared with the first rhTSH-Tg, the second stimulated Tg in these six patients decreased in one, increased in three, and stabilized in two patients.

CONCLUSIONS

The second rhTSH-Tg was informative in patients who had first stimulated Tg detectable but not in those who had undetectable Tg at the first test, in which the only patient with recurrence was diagnosed by neck US. Thus, rhTSH-Tg should be repeated only in patients who have had a positive first rhTSH-Tg and negative imaging.