ESTRO 2023 - Abstract Book

S487

Sunday 14 May 2023

ESTRO 2023

In this single center cohort analysis surgical resection and/or RT boost of macroscopic nodal disease in LACC suggest superior RNC in patients with LACC. These findings underline the need for an additional LN therapy to standard 45-50.4Gy CRT. OC-0604 HYPOCx-iRex (TCTR20210812003) a phase II RCT: 44Gy/20F VS 45Gy/25F CCRT in Cervical Cancer T. Prasartseree 1 , P. Dankulchai 1 , W. Sittiwong 1 1 Faculty of Medicine, Siriraj Hospital, Mahidol University, Department of Radiology, Division of Radiation Oncology, Bangkok, Thailand Purpose or Objective HYPOCx-iRex trial (TCTR20210812003) , a phase II RCT comparing modest hypofractionated ( HYPO 44Gy/20F ) to conventional fractionation ( CVRT 45Gy/25F) definitive concurrent chemoradiotherapy in patient with locally advanced cervical cancer, was lauched since September 2021. A pre-specified interim analysis of acute toxicity and early response rate was performed. Materials and Methods Patients with locally advanced cervical carcinoma were enrolled, excluding patient with >=3 positive pelvic LN or pathologic LN at/above common iliac region to limit the upper border of RT field for the safety screening purpose. External radiation dose was randomized to HYPO for 44 Gy (2.2Gy/F) to whole pelvis and 53 Gy (2.65 Gy/F) SIB at gross pelvic LN all in 20 five-day-a-week fractions, and for CVRT 45 Gy and 55 Gy (2.2Gy/F) in 25 fractions, respectively with VMAT concurrent with 40mg/m2 weekly cisplatin Brachytherapy planning was also randomized for conventional D2cc planning or with additional iRex parameter (DOI: 10.5114/jcb.2020.100377, not in the scope of this abstract). IGABT was performed in 4-5 once to twice weekly fractions with at least one MRI planning per GEC-ESTRO recommendation. Overall treatment time was restricted to 42 days for HYPO and 49 days for CVRT. With a target of 40 patients, an interim analysis at 3-mo follow up time of the first 20 patients was pre-specified for toxicity evaluation with CTCAEv5, tumor response, and Quality of life (QOL) with QLQ-C30, EN24 and Cx24. 13 patients in HYPO and 12 patients in CVRT received non-significant difference of HR-CTV and IR-CTV D90, and bladder, rectum, sigmoid and bowel D2cc (Table1). OTT was significantly lower in HYPO with median of 37 days comparing to 45 days in CVRT. No significant difference in terms of toxicity were observed. Specifically acute ≥ Grade 3 gastrointestinal (GI), genitourinary (GU), hematology were seen in HYPO and CVRT with 3(25%) and 4(31%), 0 and 0, 1(8%) and 3(23%), respectively. These toxicities were subsided within 3 months as shown in Table2. No significant in difference of %GTV reduction at the time of pre-brachytherapy evaluation, despite shorter time-to-brachytherapy in HYPO. Higher rate of CR was observed in HYPO, however without statistical significance (Table1). In terms of QOL, no significant difference were observed. Results 25 patients were included the report with characteristics shown in Table 1.