ESTRO 2024 - Abstract Book

S1114

Clinical - Gynaecology

ESTRO 2024

Sridhar Papaiah Susheela 1 , Anuradha Pinninti 1 , Priyasha Damodara 1 , Shalini Manjunath 1 , Nisha B 2 , Mubsureen Begam 1 , Mahesh Bandemagal 3 , Venkata Chala 3 , Abilasha Narayan 2 , Bijina TK 1 , Jerrin A 1 1 HCG, Radiation oncology, Bengaluru, India. 2 HCG, Gynec oncology, Bengaluru, India. 3 HCG, Surgical Oncology, Bengaluru, India

Purpose/Objective:

The importance of IGRT in pelvic malignancy is well established. EthosTM therapy is an Image Guided Online Adaptive Radiotherapy (IGOART) technology with an integrated suite of tools for adaptive workflow from initial planning to on-couch adaptation and treatment. This technology facilitates on-couch contour and plan adaptation to ensure target coverage and normal tissue sparing. SIB to the primary in cervical malignancy is a radiotherapy strategy that allows for the simultaneous delivery of different dose levels to the target volumes.It enables dose escalation to GTV and allows adequate / reducing the CTV ,PTV and OAR.This strategy may result in good local control with least toxicity leading to meaningful short and long term control.

Our experience with PETCT based dose escalation has shown modified target volumes, improved local control with no increase in toxicity.

We intended to exploit the technology of IGOART in association with PET CT based SIB and assess the Early Clinical Response in the patients with Locally advanced Cervical cancer, being treated with radical chemoradiotherapy.

Material/Methods:

We treated 5 patients with a median age of 50 years (38 – 56 years) with locally advanced cervical cancer with IGOART with PET CT and MRI based planning with a customised bladder protocol. All the patients underwent EBRT with IGOART and concurrent chemotherapy with weekly Carboplatin followed by HDR ICBT. All volumes were marked on basis of FDG PET CT,MRI. Simultaneous Integrated Boost technique (SIB) was employed wherein the GTV PET received 60.20Gy in 28 # (2.15Gy/#), the GTV CT/MR received 56Gy/28# (2Gy/#) and the CTV Primary(GTVPET+GTVCT+0.7-1cm) and the Elective Nodal CTV (vessels +nodal space) received 50.40Gy/28# (1.8Gy/#). OAR marked accordingly. The patients were assessed clinico- radiologically on day 0, 10, 20 and at completion of external beam radiotherapy by comprehensive clinical examination and Interim PET CT scans, and the response was compared and tracked. PET CT scan and MRI of the pelvis was also done to assess the local disease status before treatment and on follow up. The patients were followed up once at the end of the first month to assess the toxicity and thereafter once in three months for one year.

Apart from the response, acute GI/GU toxicities and QOL were assessed respectively with CTCAE v 5. and EORTC QOL 24 questionnaire weekly and on every follow up.

All patients had clinical Complete Response and 4 out of 5 patients had PET CT,MRI complete response by the end of EBRT. Which is sustained in all patients more than 6 months.No treatment interruptions occurred. The On couch time treatment time was 22 minutes (18- 28 minutes). EORTC QOL 24 Questionnaires showed a median score of 22. (18 - 28).