High prevalence of hyperthyroidism in patients with poor prognosis non seminomatous germ cell tumors

Abstract

16018 Background: Patients (pts) with metastatic non seminomatous germ cell tumors (NSGCT) with elevated beta human chorionic gonadotrophin (ß-HCG) can present with hyperthyroidism. This paraneoplastic phenomenon is due to a weak intrinsic thyroid stimulating activity of ß-HCG. The prevalence of hyperthyroidism in pts presenting with NSGCT is unknown. Methods: All consecutive metastatic NSGCT pts who presented at the UMCG between April 2001 and April 2007 were analyzed. Thyroid function was assessed by measuring thyroid stimulating hormone (TSH) and free thyroxine (FT4) levels. Hyperthyroidism was diagnosed when TSH was below normal (< 0.40 mE/L) combined with an elevated FT4 (>18.2 pmol/L). Information on disease status including International Germ Cell Cancer Classification (IGCCC), symptoms and clinical outcome was subtracted from the medical records. Results: 148 NSGCT pts were included in this analysis. Thyroid function tests 2 weeks before or within 1 week after starting chemotherapy were available for 144 pts. Prognosis was good in 86 (60%), intermediate in 37 (26%) and poor in 21 pts (14%) according to IGCCC. Five pts with hyperthyroidism (3.5%) were identified with TSH levels ranging from 0.002 to 0.21 mE/L and FT4 levels ranging from 21.3 to >75 pmol/L. Hyperthyroidism was present in 5/21 poor prognosis pts (24%) versus in none in the good and intermediate prognostic group (p<0.001). Of the pts with ß- HCG ≥ 50,000 IU/L, 50% had hyperthyroidism versus 0 % in patients with a ß-HCG < 50,000 IU/L (p<0.001). Pts presented with weight loss (n=5), fatigue (n=3), tachycardia (n=3), night sweats (n=2) and irregular pulse (n=1) as potential manifestations of hyperthyroidism. FT4 normalized < 26 days after starting chemotherapy in all pts. One pt received propranolol for tachycardias. Conclusions: Hyperthyroidism is frequently present in pts with NSGCT with poor prognosis including highly elevated ß-HCG. Since its symptoms overlap with those of extensive metastatic disease, it may not be recognized. To optimize supportive care at start of chemotherapy in poor prognosis pts, thyroid function should be known and symptomatic hyperthyroidism should be treated temporarily with beta blockade or antithyroidal medication. No significant financial relationships to disclose.