Background: Radioactive iodine therapy (RAI) is a classical therapeutic approach in patients with differentiated thyroid carcinoma (DCT). Few data are currently available on RAIs potential impacts on testicular function.
Design: A longitudinal prospective multi-center study (PHRC N°P040419) included male patients before a single radioiodine dose of 3.7 GBq of I 131 (V0), at 3 months (V3) and 13 months (V13) post treatment.
Method and Patients: Hormonal assessments (FSH, LH, Testosterone, inhibin B) as well as sperm parameters (number, mobility and morphology), DNA fragmentation and sperm FISH analysis in order to detect chromosomal abnormalities were performed at V0, V3 and V13.
Results: Thirty six patients were included in the study. At V0, all patients had normal gonadal function. At V3, FSH median levels were significantly increased as compared to V0, respectively 9 UI/l±4.8 (N: 37 UI/l) versus 4 UI/l±3 (P<0.0001). Between V3 and V13, FSH levels decreased but remained higher than baseline levels. Inhibin B median levels decreased significantly at V3 (P<0.0001) and returned to V0 levels at V13. LH and T levels were not modified at V3 or V13.
Median sperm concentration significantly decreased at V3 as compared to V0 (20 vs 48 million/ml; P<0.0001) and returned to V0 levels at V13. In parallel, a statistically significant decrease in sperm morphology was observed at V3. Sperm mobility and DNA fragmentation were not modified after RAI. However sperm chromosomal abnormalities were increased at V3 (P<0.0005) and V13 (P<0.01), as compared to V0.
Conclusion: In this prospective study, RAI transiently altered FSH, inhibin B and sperm number. Furthermore, chromosomal abnormalities observed at V3 were found to persist 13 months after RAI. Therefore, our study illustrates that counseling about fertility could be interesting in male patients with DCT treated by a single dose of radioiodine.
20 May 2017 - 23 May 2017