[Female reproductive function -after radioiodine therapy for differentiated thyroid carcinoma].

Background: Combined treatment of differentiated thyroid cancer (DTC) may have an impact on the reproductive health of patients, in particular on the ovarian reserve (OR) of childbearing-age women. However, knowledge in this area is still insufficient to create general recommendations and an algorithm for managing this cohort of patients based on their current reproductive status and desire to realize their reproductive potential.

Aim: To assess ovarian function and OR using anti-Müllerian hormone (AMH) and follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2) in dynamics in the early follicular phase in women of reproductive age receiving combined treatment for DTC.

Materials and methods: In a single-center prospective non-comparative study, the clinical and morphological, anamnestic and laboratory parameters of patients receiving combined treatment for DTC were analyzed. The levels of AMH, FSH, LH and E2 were determined in dynamics - after surgical treatment but no later than one month before radioiodine therapy (RAIT), as well as 3 and 6 months after RAIT on the background of suppressive therapy.

Results: A total of 39 women aged 18 to 40 years with a median age of 32 years [27; 37] undergoing combined treatment for DTC were enrolled in the study. The frequency of transient menstrual cycle disturbances after surgery was 18%, and after RAIT - 38%. According to the post-operative DTC status the majority of patients belonged to ATA intermediate-risk group (69%). In addition, 72% of patients received thyroid hormone withdrawal for a period of 4 weeks as a preparation for RAIT. The average activity of 131I was 3720 MBq [3050; 3838]. The levels of FSH and LH did not differ significantly before and after RAIT (R=NS). The level of E2 decreased significantly 3 months after RAIT (P<0.010), further increasing in 6 months to almost the initial values (P=NS). The level of AMH decreased significantly 3 and 6 months after RAIT compared with baseline values (P<0.001). The median AMH before the treatment was 4.10 ng/ml [2.34; 5.82], the nadir of AMH was observed after 3 months - 2.09 ng/ml [1.05; 3.05], and after 6 months AMH increased to 2.31 ng/ml [1.42; 3.37]. In 29% of patients, the AMH level decreased below the reference after 3 months. The predictor of AMH level below 1.2 ng/ml (reflecting reduced OR) 3 months after RAIT was the patient's age before RAIT. Using the Juden index, a cut-off point of 31 years was determined.

Conclusion: The level of AMH decreases significantly after RAIT for DTC, which indicates the effect of the therapy on OR, while age at the time of RAIT is the main predictor of AMH level below 1.2 ng/ml after 3 months.