ESTRO 2024 - Abstract Book

S1015

Clinical - Gynaecology

ESTRO 2024

967

Poster Discussion

Bone marrow sparing extended field CRT with ddNACT in Stage IIIC2 carcinoma cervix: a phase II study

Namrata Das 1 , Surendra Kumar Saini 1 , D N Sharma 1 , Karun Kamboj 2 , Sachin Khurana 3 , S A Shamim 4 , Raja Pramanik 3 , Dhanabalan Rajasekaran 1 , Babita Kataria 5 , Danda Vamsi Sai Praveen 1 , Swayamjeet Sathapathy 4 , Seema Singhal 6 1 AIIMS, Radiation Oncology, New Delhi, India. 2 NCI, Radiation Oncology, Jhajjar, India. 3 AIIMS, Medical Oncology, New Delhi, India. 4 AIIMS, Nuclear Medicine, New Delhi, India. 5 NCI, Medical Oncology, Jhajjar, India. 6 AIIMS, Obstetrics and Gynaecology, New Delhi, India

Purpose/Objective:

To assess the feasibility and safety profile of dose dense NACT followed by bone marrow sparing (BMS) extended field chemoradiation (CRT) in carcinoma cervix patients with para-aortic lymphadenopathy

Both systemic and local failures have to be addressed to improve outcomes for Stage IIIC2 cervix patients. To reduce the toxicities of additional NACT and extended field CRT, active bone marrow sparing of both para-aortic and pelvic bone marrow is being evaluated as a solution (CTRI/2023/03/050592: BICEP trial)

Material/Methods:

Patients with 18 FDG PET/CT staged IIIC2 carcinoma cervix patients with adequate organ reserve and performance status (ECOG 0-2) were enrolled into this phase II trial prospectively. Treatment comprised of dose dense neoadjuvant chemotherapy with six cycles of weekly paclitaxel (60 mg/m 2 ), carboplatin (AUC2) followed by chemoradiation and image guided brachytherapy. The median PTV EBRT prescription dose was 45 Gy with a simultaneous integrated boost (SIB) of 57.5 Gy and 55 Gy to the para-aortic and pelvic nodes respectively. Initial CT outlined pelvic and para-aortic bone marrow was contoured in the bone window followed by 18 FDG PET/CT based active bone marrow (ABM) delineation using the mean standardised uptake value (SUV) as a threshold. Radiotherapy planning priority was given for para-aortic and pelvic ABM sparing over small bowel. The primary endpoint was assessment of acute haematological and clinically significant gastrointestinal toxicities within the one month period of treatment completion.

Results:

Twenty one patients have been recruited from January 2023 out of which ten have completed treatment and were eligible for the primary endpoint of toxicity assessment. Patients could tolerate an average of five cycles of NACT with 20% patients developing grade 3/4 haematological toxicities during this phase. Overall response rate was 100% post NACT (20% CR, 80% PR). During radical chemo-radiation, an average of 3 cycles of concurrent chemotherapy was tolerated. The median doses and the interquartile range of the CT outlined bone marrow were: mean dose of 22.5Gy, V20Gy of 53.6% (IQR: 46-58.8) and V10 Gy of 79.6% (IQR: 77-84.1). The PET based ABM which was prioritised during planning received a mean dose of 24.6 (IQR: 23.8-25, pelvic ABM: 25 Gy, para-aortic ABM:23.3 Gy), V20Gy of 60% (IQR:57-62) and V10Gy of 87% (IQR: 84-89 Gy) all of which were within the optimal hard constraints derived from other pelvic sites. The average overall treatment time was 62 days. Nearly 80%