High prevalence of hypothyroidism among patients with cutaneous melanoma.

We have previously reported a high prevalence of hypothyroidism among patients with uveal melanoma. The objectives of the present study were to determine if a similar pattern of thyroid pathology exists among patients with cutaneous melanoma as well. To address this question, the medical records of all patients registered at the University of Texas M.D. Anderson Cancer Center with a diagnosis of cutaneous melanoma during the years 1997 and 1998 were examined for a history of overt hypothyroidism, defined as a requirement for thyroid hormone replacement. Data regarding stage and site of the primary tumor were obtained for these patients and for age/gender matched euthyroid controls from the same melanoma study population. Among 1,580 cutaneous melanoma patients (948 M/632 F), 111 (7.0%) gave a history of hypothyroidism [23/948 M (2.4%) and 88/632 F (13.9%)]. The prevalences of hypothyroidism for both males and females were significantly higher than those reported for the general population. Characteristics of the primary tumor did not differ between cases and controls, although there was a trend for a lower rate of primary tumor ulceration among the hypothyroid case subjects. We conclude that hypothyroidism of varied etiologies is common among patients with cutaneous melanoma. These data suggest that melanoma may be responsive to hormones of the thyroid hormone control loop, raising many questions of clinical and biologic importance.