Fertility sparing treatment in patients with endometrial cancer (FERT-ENC): a multicentric retrospective study from the Spanish Investigational Network Gynecologic Oncology Group (SPAIN-GOG).

Objective: The primary objective was to evaluate the response rate of conservative treatment for endometrial cancer, and the secondary objective was to assess oncological, fertility and obstetric outcomes in patients who underwent fertility preservation treatment.

Material And Methods: This multicentre, observational, retrospective study evaluated endometrial cancer patients who underwent fertility-sparing treatment in Spanish centres between January 2010 and January 2020. Seventy-three patients with stage IA endometrioid adenocarcinoma of the uterus were included in the study.

Results: The levonorgestrel intrauterine device (LNG-IUD) was the most common fertility-sparing treatment (53.4%), followed by megestrol acetate (20.5%) and medroxyprogesterone acetate (16.4%). During the 24-month follow-up period, the rate of complete response to fertility-sparing management was 74% (n = 54), and 8.2% (n = 6) of patients presented a partial response. Additionally, 13 (17.8%) patients presented with persistent disease and six (8.2%) relapsed after response. The LNG-IUD was associated with a higher complete response rate than the other methods (87.2 vs. 58.8%; p = 0.01). Surgical treatment (at least hysterectomy) was performed in 44 (60.3%) patients as the end of fertility-sparing treatment. Four (5.5%) patients presented relapse after surgery, associated with final FIGO stage III (p = 0.036), myometrial invasion > 50% (p = 0.018) and final tumour grade 2-3 (p = 0.018). The mean follow-up period was 57.8 (range 6-159) months. The 5-year relapse-free survival and overall survival rates were 92.6% [95% CI (81.3, 97.2)] and 93.5% [95% CI (80.7, 97.9)], respectively. During follow-up, three patients (4.1%) died of the disease after completion of surgical treatment. Up to 50.7% of patients included in the study attempted to get pregnant. Of these, the rate of pregnancy was 81.1% (n = 30/37), and reproductive techniques were used for this purpose in 78.4% of cases.

Conclusions: Fertility-sparing management presented a high response rate in patients with endometrial cancer. LNG-IUD was associated with a better response rate compared to the other treatment options. Moreover, in patients using this management method, pregnancy could be achieved using reproductive techniques.