Objective: This study aimed to evaluate fulvestrant efficacy in women with estrogen receptor-positive low-grade gynecological cancers. The primary objective was to determine the response rate. Secondary objectives were progression-free survival, clinical benefit, duration of response, safety, tolerability, and quality of life.

Methods: FUCHSia is an open-label, single-arm, prospective, multi-center phase II study. The study population included patients with recurrent/metastatic low-grade gynecological malignancies with estrogen receptor positivity who received a maximum of two lines of previous hormonal therapy. Patients received fulvestrant (FASLODEX, AstraZeneca) via two intramuscular injections (250 mg/5 mL each) in the gluteal muscle on day 1, day 15, day 29, and then every 28 days thereafter until disease progression, withdrawal from the trial due to any unacceptable adverse event, or withdrawal of patient consent.

Results: A total of 15 patients (uterine sarcoma n=4; sex cord-stromal ovarian tumors n=3; endometrial carcinoma n=4; serous ovarian cancer n=4) were enrolled. Median follow-up was 48 weeks (interquartile range (IQR) 26-122) in the uterine sarcoma cohort, 63 weeks (IQR 28-77) for sex cord-stromal tumors, 19 weeks (IQR 17-21) for endometrial carcinoma, and 60 weeks (IQR 40-119) for serous ovarian cancer. One partial response according to Response Evaluation Criteria in Solid Tumors v1.1 was observed in one uterine sarcoma patient. No responses were observed in the other cohorts. However, stable disease was observed in three uterine sarcomas (median duration 12 weeks), three sex cord-stromal tumors (median duration 32 weeks), and four low-grade serous ovarian cancer patients (median duration 20 weeks), leading to a disease control rate of 100% for these tumor types. All patients with endometrial carcinoma showed progressive disease.

Conclusion: Fulvestrant may control tumor growth in recurrent/metastatic estrogen receptor-positive low-grade gynecological malignancies of specific histology. Further studies are needed to confirm these results.

Keywords: Genital Neoplasms, Female; Ovarian Neoplasms; Sarcoma; Sex Cord-Gonadal Stromal Tumors.

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目标： 本研究旨在评估氟维司群在雌激素受体阳性低级别妇科癌症女性患者中的疗效。主要目的是确定反应率。次要目的包括无进展生存期、临床效益、反应持续时间、安全性和耐受性以及生活质量。

方法： FUCHSia是一项开放标签、单臂、前瞻性、多中心的II期研究。研究对象为接受过最多两线激素治疗后复发/转移低级别妇科恶性肿瘤且雌激素受体阳性的患者。患者通过两次臀肌内注射（每次250毫克/5毫升）给予氟维司群（FASLODEX，阿斯利康），即第1天、第15天、第29天以及之后每28天一次，直至疾病进展或因任何不可接受的不良事件退出试验或患者撤回同意为止。

结果： 共纳入了15名患者（子宫肉瘤4例；性索-间质卵巢肿瘤3例；子宫内膜癌4例；浆液性卵巢癌4例）。在子宫肉瘤队列中的中位随访时间为48周（四分位距(IQR) 26-122），性索-间质肿瘤为63周（IQR 28-77），子宫内膜癌为19周（IQR 17-21），浆液性卵巢癌为60周（IQR 40-119）。根据实体瘤疗效评价标准v1.1，一名子宫肉瘤患者出现了一次部分反应。其他队列中未观察到任何反应。然而，在三名子宫肉瘤（中位持续时间12周）、三个性索-间质肿瘤（中位持续时间32周）以及四例低级别浆液性卵巢癌患者（中位持续时间20周）中均观察到了病情稳定，导致这些类型的肿瘤控制率为100%。所有子宫内膜癌患者均显示疾病进展。

结论： 氟维司群可能能够抑制特定组织学类型的复发/转移低级别雌激素受体阳性妇科恶性肿瘤的生长。需要进一步的研究来确认这些结果。

关键词： 生殖系统肿瘤；女性卵巢肿瘤；肉瘤；性索-间质肿瘤。