Quantifying the Therapeutic Benefit of External Beam Radiotherapy in Uterine Serous Carcinoma: A Real-World Study
Author(s)
Eleftherios samartzis, MD1, Lucy Gilbert, MD2, Vincent McCarty, MSc3, Neil R. Brett, PhD4, Marielle Bassel, BA4, John S. Sampalis, MSc, PhD4.
1University Hospital Zürich, Zurich, Switzerland, 2Department of Oncology, McGill University, Montreal, QC, Canada, 3Department of Surgery, McGill University, Montreal, QC, Canada, 4PPD™ Observational Studies, Thermo Fisher Scientific, Montreal, QC, Canada.
1University Hospital Zürich, Zurich, Switzerland, 2Department of Oncology, McGill University, Montreal, QC, Canada, 3Department of Surgery, McGill University, Montreal, QC, Canada, 4PPD™ Observational Studies, Thermo Fisher Scientific, Montreal, QC, Canada.
OBJECTIVES: Uterine serous carcinomas (USC) have a poor prognosis despite treatment, and account for 40% of Endometrial Cancer related deaths. External beam radiotherapy (EBRT) adjuvant to chemotherapy is common treatment. Views differ regarding the utility of EBRT in USC. The objective was to assess the incremental therapeutic benefit of adjuvant EBRT in patients with USC.
METHODS: This retrospective observational cohort study at McGill University Health Center (2008-2023), examined USC patients treated with chemotherapy alone or with adjuvant EBRT, with up to 5-year follow-up. Multivariate logistic regression and Receiver Operator Curve (ROC) analyses were performed to assess effectiveness and identify responders to treatment.
RESULTS: 50 patients receiving chemotherapy (C) and 61 receiving chemotherapy with adjuvant EBRT were identified. Mean (SD) age of the C and EBRT groups were 67.3(9.1) and 69.3(8.0) years respectively (P=0.219). The proportion with stage III/IV disease was C:74%, EBRT:30% (P<0.001) and the proportion with malignant cytology was C:52.0%, EBRT:15.5% (P=0.046). The adjusted hazard ratio (HR [95%CI]) for progression-free survival for EBRT was 0.503 (0.221-1.145; P=0.101). Logistic regression analysis identified older age, FIGO stage (III/IV), progesterone receptor-positive and malignant cytology as predictors of progression in the EBRT group. ROC analysis identified three distinct groups with high (31.2%; OR=0.267), intermediate (22.6%; OR=0.375) and low (46.2%; OR=1.038) potential benefit of EBRT in preventing progression. Numbers needed to treat were 3.5, 4.2 and 176 respectively. Restricting EBRT to the high and intermediate benefit groups would prevent 32/50 (64%) non- beneficial exposures to EBRT along with the associated reductions in expenditures and impact on patient Quality of Life.
CONCLUSIONS: Results suggest that using clinical decision algorithms for adjuvant EBRT in USC may enhance treatment benefit and cost-effectiveness. This should be confirmed by additional RWE studies. The study underscores the value of real-world evidence in optimizing treatment effectiveness and patient benefits.
METHODS: This retrospective observational cohort study at McGill University Health Center (2008-2023), examined USC patients treated with chemotherapy alone or with adjuvant EBRT, with up to 5-year follow-up. Multivariate logistic regression and Receiver Operator Curve (ROC) analyses were performed to assess effectiveness and identify responders to treatment.
RESULTS: 50 patients receiving chemotherapy (C) and 61 receiving chemotherapy with adjuvant EBRT were identified. Mean (SD) age of the C and EBRT groups were 67.3(9.1) and 69.3(8.0) years respectively (P=0.219). The proportion with stage III/IV disease was C:74%, EBRT:30% (P<0.001) and the proportion with malignant cytology was C:52.0%, EBRT:15.5% (P=0.046). The adjusted hazard ratio (HR [95%CI]) for progression-free survival for EBRT was 0.503 (0.221-1.145; P=0.101). Logistic regression analysis identified older age, FIGO stage (III/IV), progesterone receptor-positive and malignant cytology as predictors of progression in the EBRT group. ROC analysis identified three distinct groups with high (31.2%; OR=0.267), intermediate (22.6%; OR=0.375) and low (46.2%; OR=1.038) potential benefit of EBRT in preventing progression. Numbers needed to treat were 3.5, 4.2 and 176 respectively. Restricting EBRT to the high and intermediate benefit groups would prevent 32/50 (64%) non- beneficial exposures to EBRT along with the associated reductions in expenditures and impact on patient Quality of Life.
CONCLUSIONS: Results suggest that using clinical decision algorithms for adjuvant EBRT in USC may enhance treatment benefit and cost-effectiveness. This should be confirmed by additional RWE studies. The study underscores the value of real-world evidence in optimizing treatment effectiveness and patient benefits.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
CO198
Topic
Clinical Outcomes
Topic Subcategory
Clinical Outcomes Assessment
Disease
Oncology