2823 - Development of a Validated Radiation Score for Treatment Compliance in Gynecological Cancer Patients Receiving Radiation Therapy

Purpose/Objective(s): The requirement of intensive multimodal therapy in the treatment of gynecological cancers highlights the necessity to understand the impact of patient and treatment related factors in successful completion of the treatment. The objective of this study is to evaluate these variables to enhance adherence to required treatment schedule, thereby maximizing therapeutic benefits. We aim to provide a validation score for each significant factor and assess the combined influence of these parameters on treatment duration.

Materials/Methods: We conducted a multi-hospital, single-institution review of treatment parameters and patient characteristics related to successful completion of radiation therapy. The patient characteristics examined included age, ECOG performance status, comorbidities, and primary cancer site. Treatment parameters included RT fields, number of fractions, and the use of sequential or concurrent systemic therapy, with or without surgery. Each parameter was assigned a validation score of 0 to 1 or up to 7, aggregated into a total score (0-35). Univariate logistic regression analysis, ROC curve and sensitivity-specificity analyses were employed to evaluate the association between predictors and treatment completion. Multivariate analysis was not performed due to insufficient events of interest observed. Independent predictors were analyzed using a univariate logistic regression model.

Results: 82 patients from a cohort of 142, treated between June 2024 and January 2025 were assessed for completion of radiation in 8-week timeframe and treatment termination for any reason as the endpoint measure to test the proposed validation score. Our findings indicate a significant association between the total score and treatment outcomes, whether early termination or prolonged treatment (p=0.009, OR 1.26, 95% CI 1.06-1.51) with a cutoff at score 18. In further analysis, factors such as RT fractions, primary cancer site, systemic therapy, and surgery were independently associated with outcomes. An increase in RT fractions above median 28, escalates the odds of treatment delay by 41% (OR=1.41, 95% CI:1.09-1.83, p=0.008). Vagina/cervix as primary cancer site linked to increased odds of delay (OR=9.49, 95% CI: 2.36-38.25, p=0.034). CCRT raises the risk of extended treatment (OR=17.78, 95% CI: 2.14-147.87, p=0.008), with pre-RT chemotherapy shows no association (OR=2.45, 95% CI: 0.21-29.21, p=0.472). Absence of surgery significantly increases treatment extension likelihood (OR=7.48, 95% CI: 2.24-24.92, p=0.001).

Conclusion: The proposed validation score successfully predicts certain variables associated with successful treatment completion, with greater odds for shorter fractionation courses, non-cervix/vaginal sites, no concomitant systemic therapy, and post-operative patients. Engaging certain patient subsets, underscores the need for personalized treatment plans and strategic interventions to improve therapy schedule adherence.