Objective: To estimate the effectiveness of gonadotropin-releasing hormone (GnRH) analogues cotreatment in preventing chemotherapy-induced amenorrhea in young breast cancer patients undergoing cyclophosphamide-based chemotherapy.
Methods: One hundred hormone-insensitive breast cancer participants (aged 18-40 years) were recruited from two university-affiliated oncology centers in Egypt. Opting for type of cotreatment was based on available timeframe until start of chemotherapy. Fifty women ready for early chemotherapy were randomized to receive either chemotherapy alone (arm I) or chemotherapy after downregulation (estradiol less than 50 pg/mL) by GnRH antagonist and agonist (arm II). Then, GnRH antagonist was discontinued and agonist was continued until the end of chemotherapy. When chemotherapy was to start later than 10 days after study inclusion, 50 women were randomized to receive either chemotherapy alone (arm III) or chemotherapy after downregulation with GnRH agonist (arm IV). Resumption of menstruation at 12 months after end of chemotherapy was the primary outcome. Postchemotherapy hormonal and ultrasound changes were secondary outcomes.
Results: Twelve months after termination of chemotherapy, there were no differences in menstruation resumption rates between GnRH-treated patients and control group individuals in either early (80% in arms I and II, risk ratio 1, 95% confidence interval 0.7-.32; P=1.00) or delayed chemotherapy groups (80% and 84% in arms III and IV, risk ratio 0.95, 95% confidence interval 0.73-1.235; P=.71). There were no differences in hormonal and ultrasound markers between GnRH analogue users and control group individuals. The use of GnRH analogue cotreatment did not predict independently the odds of menstruating at 12 months.
Conclusion: GnRH analogue cotreatment does not offer a significant protective effect on ovarian function in patients treated by cyclophosphamide-based chemotherapy.
Clinical trial registration: Australian New Zealand Clinical Trials Registry. www.anzctr.org.au, ACTRN12609001059257.
Level of evidence: I.