ESTRO 2025 - Abstract Book

S2258

Interdisciplinary – Health economics & health services research

ESTRO 2025

11

Digital Poster Effectiveness and Utility of the CECIL Patient Decision Aid for Cisplatin-Intolerant Cervical Cancer Patients (NCT05701735) Warren Bacorro 1,2 , Aida Bautista 3 , Genalin Amparo 4 , Irene Tagayuna 5 , Jennifer Madera 6 , Carl Jay Jainar 2 , Vannesza Chua 2 , Gonzalo Banuelos 2 , Kathleen Baldivia 2 , Jocelyn Mariano 7 , Gil Gonzalez 7 , Teresa Sy Ortin 2 , Michala Short 8 , Rodel Canlas 1 1 Graduate School, University of Santo Tomas, Manila, Philippines. 2 Department of Radiation Oncology, University of Santo Tomas Hospital – Benavides Cancer Institute, Manila, Philippines. 3 Department of Obstetrics and Gynecology, Manila Doctors Hospital, Manila, Philippines. 4 Department of Obstetrics and Gynecology, Our Lady of Lourdes Hospital, Manila, Philippines. 5 Department of Obstetrics and Gynecology, De Los Santos Medical Center, Quezon City, Philippines. 6 Department of Obstetrics and Gynecology, Chinese General Hospital and Medical Center, Manila, Philippines. 7 Department of Obstetrics and Gynecology, University of Santo Tomas Hospital, Manila, Philippines. 8 Department of Radiation Oncology, University of South Australia, Adelaide, Australia Purpose/Objective: In cervical cancer, adding chemotherapy to radiotherapy improves survival but increases toxicity. In patients with contraindications, cisplatin or its substitute may decrease radiotherapy compliance due to toxicity. We evaluated the effectiveness (primary objective) and utility (secondary objective) of the CECIL, a previously validated patient decision aid (PtDA) for chemotherapy or its exclusion in these patients. Material/Methods: A block-randomized controlled trial was conducted to evaluate the effectiveness of the PtDA in reducing decisional conflict as measured by the Decisional Conflict Scale (DCS) and its utility as measured by the Preparation for Decision Making Scale (PDMS). To detect a 0.40 difference in group proportions with low post-intervention DCS (<25), 16 and 24 participants for the control and experimental groups were required for a two-sided 0.10 alpha error and 0.90 power. To detect utility (≥75% reporting PDMS≥3.5), 24 participants in the experimental group were required for a one-sided 0.10 alpha error and 0.90 power. Assuming 10% attrition, we targeted for 18 and 27 participants into the control and experimental groups. Age, education, socioeconomic status, and decision self-efficacy as measured by the Decision Self-Efficacy Scale (DSES), were studied as determinants of outcomes. Results: From February 2023 to August 2024, 8 and 10 participants were recruited into the control and experimental groups. On interim analysis at 43% accrual, there was 0.15 difference in the proportions with DCS<25 (0.75 control, 0.90 experimental, z-value -0.85). The futility index was 0.999, thus our decision for trial closure. Nevertheless, mean post-intervention DCS was lower in the experimental than in the control group (11.6 versus 19.3, p=0.07). Among the PtDA users, 80% reported a PDMS of ≥3.5, indicating utility in preparation for decision making. The highest scored utilities were: preparing to talk to their doctor regarding what matters to them (4.6); preparing to make a better decision (4.5); preparing to think about how involved they want to be in the decision (4.5); preparing for a follow-up visit with their doctor (4.5); and identifying questions they want to ask their doctor (4.4). Among the studied variables, only decision self-efficacy was a strong determinant for post-intervention DCS ( r =- 0.879) and utility ( r =0.836). ANCOVA confirmed that both decision self-efficacy (ω²=0.392, p<0.01) and PtDA use (ω²=0.146, p=0.02) were independent determinants of post-intervention DCS. Conclusion: The CECIL reduces mean decisional conflict scores and is utile in preparation for decision making. Decision self efficacy is a strong determinant for post-intervention decisional conflict and PtDA utility.