3495 - Clinical Outcomes of Stage IVB Gynecologic Malignancies Treated with Definitive Radiotherapy

K. Dibs¹, A. Yaney¹, T. Andraos², D. D. Martin², and A. M. Quick²; ¹The Ohio State University Wexner Medical Center, Columbus, OH, ²Department of Radiation Oncology, The Ohio State University Wexner Medical Center, Columbus, OH

Purpose/Objective(s): The standard approach for managing stage IVB gynecologic malignancies (GMs) is not firmly established. Systemic therapy stands as the central treatment for these conditions, with patients (pts) showing survival improvement when treated with immune therapy. Although palliative radiotherapy and debulking surgeries may be implemented for symptom control, adopting more aggressive loco-regional treatments entailing definitive radiotherapy with or without definitive surgery could potentially improve patients’ outcomes. We are presenting patients update and longer follow-up. Materials/

Methods: A retrospective analysis of stage IVB GMs treated between 2015-2023. Pts were treated with aggressive intent regimen consistent of chemotherapy and radiation with or without curative surgery. Overall survival defined as the time from diagnosis to the date of death. Progression free survival was defined as the time from diagnosis to recurrent/progressive disease. Local control was defined as the time from diagnosis to recurrent/progressive disease in the field of radiation.
Results: 24 pts were identified, with a median age of 58 yrs (range: 25-72). The majority, 22 pts (92%) had ECOG performance status of 0-1 according. 11 pts (46%) had cervical primary, 10 pts (42%) had endometrial cancer, and the remaining 3 pts (12%) had vulvar cancer. Regarding histology, 12 pt (50%) had adenocarcinoma, 9 pts (38%) had squamous cell carcinoma, and the remainder were diagnosed with either clear cell or neuroendocrine tumor. 13 pts (54%) underwent curative surgery before proceeding with radiation. The median prescribed dose was 45 Gy (range: 42-55) delivered via intensity modulated radiation therapy (IMRT) or volumetric modulated arc therapy (VMAT) in 22 pts and 2 pts had 3D conformal radiotherapy (3DCRT). One of the pts received 42Gy twice daily over 28 fractions. 15 pts (63%) treated with extended field radiotherapy. 11 pts (45%) received brachytherapy with median dose of 17.5 Gy (range: 12-27.5). 11 pts (45%) had concurrent chemoradiotherapy with cisplatin. All patients treated with different chemotherapy combination with or without targeted therapy or immune therapy. At a median follow-up of 43.2 months (range: 3.7-100.5), the 3-year- OS was 65%, PFS was 55%, and local control was 86%. Pts who had curative surgery had better OS and PFS (3-year OS 82% vs. 50%, p .05; 3-year PFS 73% vs. 40%, p .05). The PFS tend to be worse among the 5 pts who were unable to complete radiotherapy (3-year PFS 62% vs. 40%, p .06). Clear cell and neuroendocrine histologies had worse OS (HR 14.65 [CI 2.01-106.5], p .008) and PFS (HR 11.7 [CI 1.61-84.72], p .015). There was no correlation between the number of metastatic sites with OS (HR 0.57 [CI 0.15-02.16], p .41) or PFS (HR 0.49 [0.13-01.78], p .28)
Conclusion: Aggressive loco-regional treatment with stage IVB GM may improve pts outcomes. For cases deemed operable, curative surgical intervention could be considered. A larger number of pts and prospective trials are warranted.