ESTRO 2022 - Abstract Book

S1150

Abstract book

ESTRO 2022

PO-1355 The treatment strategy for cervical cancer; image-guided HDR-ICBT and IMRT using central shielding

Y. Mukai 1

1 University Graduate School of Medicine, Radiation Oncology, Yokohama, Japan

Purpose or Objective We previously reported the importance of combination therapy of standard external beam radiation therapy that combines whole pelvic radiation therapy (WPRT) and sequential WPRT with central shielding (WPRT-CS) and high-dose-rate intra- cavity brachytherapy (HDR-ICBT). Recently, we introduced 3D image-guided HDR-ICBT. This study aims to evaluate the treatment outcome and toxicities of the combination therapy of EBRT using IMRT/TomoTherapy, including WPRT and WPRT-CS and image-guided HDR-ICBT. Materials and Methods We included 52 consecutive patients treated for non-metastatic uterine cervical cancer from August 2011 to April 2021 in this retrospective analysis. The median age of patients was 64 (range, 30-90) years old, and the performance status (PS) was as follows; PS0: 41, PS1: 10, PS2: 2. All patients had a histopathological diagnosis of uterine cervical cancer, and 46 patients had squamous cell carcinoma (SCC), and the remaining 6 had adenocarcinoma. Primary tumor stages (FIGO) were distributed as follows: IB: 6, IIA: 5, IIB: 12, IIIB: 3, IIIC1:19, IIIC2:4 (with Para-aortic lymph node metastasis), and IVB: 2. The median dose of WPRT and WPRT-CS was 36 (range, 22–43.2) and 14.4 (range, 9–28) Gy, respectively. Median HDR-ICBT dose/fractions to Point A was 24Gy/5 Fr (range, 15–30 Gy/3–6Fr). Only one patient developed multiple lung metastases during radiation therapy and terminated local treatment. She was excluded from this analysis. Results The median follow-up time was 62.5 (range 2-122) months. The three and 5-year overall survival (OS), progression-free survival (PFS), and local control of primary tumor (LC) rates were 90.8% and 87.4 % in OS, 89.61% in PFS, and 96% in LC, respectively. Chemotherapy given concomitantly with RT consisted of weekly cisplatin administration (40 mg/m2 of the body surface area) and was assigned to 41 of the 51 patients (82 %) in 2–6 courses, with a median of 5 courses. Nine of 51 patients received image-guided HDR-ICBT. The median D2cc values for the rectum, bladder ( α / β =10 for EBRT plus HDR-BT) are 80.6 and 71.4 Gy EQD2, respectively. All acute toxicities were tolerable/manageable, and no patient had ≥ Grade 3 gastrointestinal and genitourinary acute and late toxicities Conclusion This study demonstrated an excellent LC rate and favorable OS and PFS. Further studies are needed to confirm the treatment to determine the long-term efficacy and late toxicity. 1 Dr Ram Manohar Lohia Institute of Medical Sciences , Department of Radiation Oncology , Lucknow, India; 2 Dr Ram Manohar Lohia Institute of Medical Sciences , Department of Obstetrics and Gynaecology , Lucknow, India Purpose or Objective To evaluate the early clinical outcome and acute toxicity profiles in patients with locally advanced carcinoma cervix (LACC) treated with image guided intensity-modulated radiation therapy (IG-IMRT) and image-guided brachytherapy (IGBT). Materials and Methods Between December 2019-August 2021, 20 patients of squamous cell carcinoma cervix with stage IB2-IIIC1 (FIGO 2018) were recruited in to this single arm prospective interventional study (CTRI/2020/08/027434). Whole pelvis IG-IMRT was delivered to a dose of 45Gy in 25 fractions with daily KV-CBCT (IIIC1 patients received 55 Gray in 25 fractions as nodal boost) with concurrent weekly cisplatin (40 mg/m2). Patients received IGBT of 7 Gy × 4 fractions to the High-Risk Clinical Target Volume (HR-CTV). The first fraction was done under MRI guidance and subsequent fractions under CT guidance. Acute toxicity was graded according to the Common Terminology Criteria for Adverse Events, version 5.0. The primary and secondary endpoints were acute toxicity and loco-regional control at 6 months, respectively. Results Patient characteristics are summarized in table 1. Median RT dose was 45Gy (45-55Gy). All patients received concurrent chemotherapy with median number of 5 cycles (4-5). Median overall treatment time was 8 weeks (7-10.5weeks). The median cumulative doses in terms of equivalent dose of 2 Gy (EQD2) of IGBT plus WP-IMRT for D90HR-CTV,D2cc bladder,D2cc rectum, and D2cc sigmoid colon were 87Gy (81-95.8Gy), 72.95Gy (65.3-83.2Gy), 63.1Gy (57.8-68.8Gy) and 65.6Gy (61.2-75.2Gy), respectively. At the median follow-up of 12.5 months (6.6-19.6months), none of the patient reported grade 3 or 4 acute toxicity. Grade 1 and 2 diarrhea, grade 1 cystitis was reported in 3 (15%), 2(10%) patients and 2(10%) PO-1356 Early Clinical Outcome and Acute Toxicities in Carcinoma Cervix Treated with IG-IMRT and IGBT V.K. Mishra 1 , M. Rastogi 1 , A.K. Gandhi 1 , R. Khurana 1 , R. Hadi 1 , S. Sapru 1 , S.P. Mishra 1 , A.K. Srivastava 1 , A. Bharati 1 , N. Singh 2