Recombinant human thyrotropin to help confirm lack of evidence of radiation-induced differentiated thyroid cancer in young women seeking pregnancy.

BACKGROUND Women with a history of differentiated thyroid carcinoma who are contemplating pregnancy may wish reassurance regarding apparent remission. However, the thyroid hormone withdrawal needed to obtain serum thyroglobulin testing (Tg) results in weeks-long biochemical and clinical hypothyroidism, which could increase miscarriage and fetal death rates if pregnancy occurred during withdrawal of thyroxine or soon thereafter. Recombinant human thyrotropin (rhTSH) elevates thyrotropin exogenously, allowing uninterrupted thyroid hormone therapy and avoids hypothyroidism. MATERIAL AND METHODS Thirty female radiation-induced papillary thyroid carcinoma survivors who had undergone total- or near-total thyroidectomy and who were now seeking pregnancy (mean age 23.9 ± 1.8 years), and who were considered cancer-free by local standards, underwent rhTSH-aided Tg testing to help confirm remission. At the time of rhTSH testing, mean follow-up after primary surgical treatment was 11.1 ± 3.9 years, and all patients had negative neck ultrasonography, undetectable unstimulated serum Tg (< 0.2 ng/mL) and no interfering anti-Tg antibodies. However, based on T3, N1 or M1 status, 28/30 (93.3%) patients had high recurrence risk. RESULTS rhTSH produced no serum Tg increase in 27/30 women (90.0%). Serum Tg increases to 0.4-0.9 ng/ml were observed in 3 women, but careful neck ultrasonography found no lymphadenopathy. Reassured about their remission, 14/30 women (46%) have become pregnant and delivered healthy children in the 3 years since rhTSH-aided testing. CONCLUSIONS rhTSH-aided Tg testing is useful in confirming absence of tumor in female patients with a history of radiation-induced thyroid cancer who are seeking pregnancy, but who also have a high risk of thyroid cancer recurrence.