The efficacy and tolerability of short-term low-dose estrogen-only add-back therapy during post-operative GnRH agonist treatment for endometriosis

Treatment protocol. Immediately after surgery and then at one-monthly intervals, a GnRH agonist was administered (six treatments in total). Add-back therapy was performed for five months beginning one month after surgery. Ultrasound and CA-125 level were evaluated two months after the last GnRH agonist treatment.

The incidence of symptoms during GnRHa treatment with add-back therapy over five months of add-back treatment. Incidence refers to at least one occurrence of symptoms. The incidence of symptoms was not significantly different between the two add-back treatment groups.

The frequencies of hot flashes and uterine bleeding with time. (A) Hot flashes. (B) Uterine bleeding. Patients received daily add-back therapy beginning at the same time as the second GnRHa injection (second month). The frequency of hot flashes was high in the first month after the initiation of add-back therapy, but decreased markedly in the second month in both groups. The incidence of hot flashes each month was not significantly different between the two groups. The incidence of uterine bleeding decreased with time and was less common in group B than group A patients from the second month after the start of add-back therapy; however, this difference was not statistically significant.