ESTRO 2022 - Abstract Book

S1133

Abstract book

ESTRO 2022

Data of 63 EC patients treated at our centre between 2013-2020 were retrieved from our departmental archives. Patients were analysed for demographic details, histopathological findings, details of surgery and histopathology (HPE), results of review of HPE, adjuvant treatment details and clinical outcome. All patients with HPE outside our institute are routinely reviewed at our center prior to initiation of treatment. In cases of discordance, patients are discussed in the multi- disciplinary tumour board for final treatment decision. Patients were staged as per FIGO (International Federation of Gynaecology and Obstetrics) 2018.Radiotherapy was delivered with 3D-conformal radiotherapy and concurrent chemotherapy was given with cisplatin 50 mg/m 2 (Day 1 and 28). Adjuvant chemotherapy consisted of 4 cycles of 3 weekly paclitaxel (175mg/m 2 ) plus carboplatin (AUC 5) Results Median age was 57 years (range 30-77). 69.8% had medical co-morbidities. Patient characteristics and treatment details are summarized in table 1. 5 patients had ovarian involvement. Of the biopsy blocks reviewed, changes were observed in 10 patients (16%). HPE review changes were observed in terms of histological grade in 5 patients (50%), histological type in 1 (10%), myometrial invasion in 4 (25%) and lymph node involvement in 2 (20%). HPE review lead to changes in the management of 6 patients for overall cohort (10%). Median external beam radiotherapy dose was 50 Gray (range 45-50.4 Gray at 1.8-2 Gray per fraction). Median brachytherapy dose for patients treated with brachytherapy alone was 7 Gray each for three sessions and in combination with EBRT was 6 Gray each in 2 sessions. Median number of adjuvant chemotherapy cycles were 4 (range 2-4). At a median follow up of 26 months, 7 (12%) patients developed distant metastasis, 2 (3.2%) patients had local recurrence.

Conclusion Endometrial carcinoma patients treated at our center have excellent local control rates with multimodality management. Central histopathological review may lead to changes impacting patient management and should be routinely done prior to initiation of treatment in endometrial carcinoma.

PO-1337 Adaptive 3-D ICBT Treatment Plans for cervical cancer: Target Volume vs. High Central Dose Profiles

R. Kim 1 , S. Strickler 1 , S. Marcrom 2 , X. Wu 1

1 University of Alabama at Birmingham, Radiation Oncology, Birmingham, USA; 2 University of Alabama at Birmingham, Radiation Oncology, Birmingham , USA Purpose or Objective Intracavitary brachytherapy (ICBT) not only provides conformal dose delivery, but also delivers a high central dose (HCD) to the target which cannot be reproduced by IMRT or SBRT. The ABS and SGO do not recommend conformal external beam boost due to inferior local control and survival. The ideal HCD profile for tumor control is a matter of debate. It is well known that various treatment plans with different image-guided (IG) target definitions can equally conform to HR-CTV and limit dose to organs at risk (OARs) for medium-sized ICBT targets. However, HCD profiles in various treatment plans (TP) have not been compared in the past. Target definition of HS-CTV is the most critical for IG-ICBT. The purpose of this study is to compare HCD profiles between conventional Point A and IG-ICBT plans with different target definitions. Materials and Methods Five ICBT TP with different target definition were used to compare HCD profiles. Each TP was run on three tumor sizes – small, medium, and large. A patient with FIGO stage IB2 cervical cancer was selected for the medium-sized HR-CTV. A large target was created by adding a 1.0 cm symmetric expansion and a small target by subtracting 0.5 cm symmetrically. The