The effects of post‐surgical administration of goserelin plus anastrozole compared to goserelin alone in patients with severe endometriosis: a prospective randomized trial

BACKGROUND: Among patients using GnRH analogues for endometriosis it has been postulated that peripheral and inflammation‐induced in‐situ aromatization of adrenal androgens are probably the main reasons for the high rates of failure during follow‐up. We hypothesized that in cases with premenopausal severe endometriosis, use of a combination of anastrozole and goserelin to achieve almost maximal endocrine blockade of estrogen synthesis after conservative surgery may increase the pain‐free interval and reduce the recurrence rates as compared to goserelin alone. METHODS: In a prospective randomized trial, we evaluated the efficacy of using either a combination of anastrozole and goserelin for 6 months or goserelin alone for 6 months after conservative surgery for severe endometriosis. The primary outcome measures were the symptom recurrence rates and the impact of treatment on endometriosis‐related multidimensional score. The secondary outcome measures were the impact of allocated treatment regimens on menopausal quality of life and on lumbar spine bone mineral density (BMD). RESULTS: When we analyzed the Kaplan–Meier survival curves, we detected a statistically significant advantage of goserelin plus anastrozole as compared to goserelin only, in terms of the median time to detect symptom recurrence (>2.4 versus 1.7 months; log‐rank test; P = 0.0089). This statistically significant advantage occurred with a relative risk of 4.3 [95% confidence interval (CI) 1.3–9.8]. Three cases out of 40 recurred in the goserelin plus anastrozole arm (7.5%), whereas we detected recurrences in 14 cases out of 40 cases in the goserelin‐only arm (35%) during the follow‐up period of 24 months. Based on these data, the interpretation of Kaplan–Meier curves indicates that at the end of follow‐up, 54.7 versus 10.4%, respectively, of the patients were free of recurrence. The mean of the differences in terms of Δbaseline–24 months post‐medical therapy multidimensional score were statistically significant in favour of goserelin and anastrozole (9.2 ± 2.1 versus 6.7 ± 2.8; paired t‐test; P < 0.0001; 95% CI 1.5–4.0). We observed a statistically significant difference in suppression of estradiol concentrations and a significantly greater BMD loss at the end of treatment in the goserelin and anastrozole arm as compared to goserelin‐only arm. However, this did not elicit deterioration in menopausal quality of life and the observed bone loss was not significant in terms of ΔBMD between the