Abstract book - ESTRO meets Asia

S81 ESTRO meets Asia 2018

PO-199 Cardiac dose reduction with DIBH technique in left breast cancer patients- An institutional study. D. Borade 1 , S.K. Shrivastava 1 , S. De 1 , S. Choudhari 1 , A. Churi 1 , A. Bargundi 1 , S. Nair 1 1 Apollo Hospitals, Radiation Oncology, Navi Mumbai, India Purpose or Objective The deep inspiration breath-hold technique (DIBH) has been introduced into clinical practice to reduce the radiation dose to the heart. The aim of the present study was to evaluate the application of intensity modulated radiotherapy (IMRT) in DIBH using Varian's Real-time Position Management™ (RPM) system at Apollo Hospitals, Navi Mumbai, with a special emphasis on treatment planning and dosimetric parameters and the time efficiency. Material and Methods All patients with left-breast cancer treated between July 2017 and May 2018 were included. Radio-graphs are used as simple screening criteria at CT simulation, to assess patients for obvious DIBH benefit and capability. Selected patients received forward-planned intensity-modulated RT (IMRT) based on a DIBH CT scan. Varian's Real-time Position Management™ (RPM) system was used for DIBH positioning during gated radiation delivery. Patient, target set-up, and OAR dose information were collected at treatment. Results Comparison of free-breathing (FB) and DIBH treatment plans for five patients confirmed DIBH reduced heart radiation (mean heart dose by 43%, mean left anterior descending (LAD) artery dose by 39%). Thirty left breast cancer patients completed the treatment successfully with DIBH, three patients failed to do DIBH due to poor lung capacity. Low OAR doses were achieved overall: the mean heart dose was 3.9 (range, 0.95-8.9) Gy, and the mean ipsilateral lung dose was 9.18 (range, 5.88-11.7) Gy. Post mastectomy status and supraclavicular fossa node coverage were associated with increased heart dose. Conclusion DIBH technique using Varian's Real-time Position Management™ (RPM) system showed significant reduction in cardiac dose. In our study, we confirmed reliability and time efficiency of implementing DIBH for left breast cancer patients with good lung function. PO-200 Parameters defying the cardiac dose reduction benefit of DIBH in left breast cancer radiotherapy U. Saxena 1 , A. bhange 1 , P. Ganeshan 1 , A. Karuppusamy 1 , T. Basu 1 , N.Bbhaskar 1 , S. Vangipuram 1 , D. Sen 1 , S. Maurya 1 , S. thacheril 1 , S. Sebastian 1 1 HCG Apex Cancer Centre, Radiation Oncology, Mumbai, India Purpose or Objective Breast cancer (BC) radiation therapy (RT) techniques have evolved over time from bitangetial 2D technique to conformal radiotherapy. With improving survival in breast cancer patients, new advancements in technologies have helped to reduce treatment related morbidity. Deep inspiratory breath hold (DIBH) technique has been well established to reduce cardiac doses in left sided BC. We intended to study the excursion of heart and chest wall in DIBH scan versus free breathing (FB)scan in left sided BC and its cardiac dose reduction with the intent of identifying factors which causes no cardiac dose reduction in some cases. Material and Methods Fifteen patients of left sided BC were included in study. All the patients were simulated using board with 2.5 m plain CT scans done in FB and DIBH using active breath coordinator (ABC). RTOG based contours were made and

3DCRT- field in field plans were generated. Parameters of heart such as cranial and caudal border, distance of heart from chest wall at T7-T8 vertebral level and at cardiac apex level, lung 3D dimensions were noted in both FB as well as DIBH scan. The variation in excursion of heart position and lung dimension in FB and DIBH scan was correlated to cardiac doses (Mean Heart dose). Results Mean cranio-caudal shift of heart in DIBH to FB was 2.1cms (Range: 1.5-3cms), mean displacement of heart from chest wall at T7-T8 level was 3.12cms in FB (Range: 2- 4.3cms) and 5.06cms in DIBH (Range: 4.7-5.8cms) and at cardiac apex was 2.46cms in FB (Range: 2-3.1cms) and 3.7cms (Range: 3.2-4.2cms). Mean lung dimension in supero-inferior (SI) direction was 14.4cms in FB and 17.75cms in DIBH, mean lung dimension in transverse direction at T7-T8 level was 7.35cms in FB and 8.4 cms DIBH, at basal level it was 8.3cms in FB and 9.5cms in DIBH, mean AP lung dimension at T7-T8 level was 13.4cms in FB, 14.4cms in DIBH and at basal level 13.5cms in FB and 14.4cms in DIBH. Mean heart dose in FB was 6.4Gy (Range: 5.8-7.8Gy) and in DIBH it was 2.4Gy (Range: 2.1- 4Gy), mean LAD dose reduction in DIBH was 30%. DIBH caused expansion of the chest with chest wall excursion of 3-10mm while pushing heart postero-inferiorly. It resulted in increased cardiac chest wall distance and low isodose or in some cases, no isodose passing through heart and LAD. This reduced the heart and LAD doses in DIBH. In some cases lateral expansion was minimal or there was no posterior shift of heart during DIBH, hence not much reduction was seen in cardiac doses. Conclusion DIBH is an established technique of dose reduction to heart in breast cancer radiotherapy. Some cases however do not benefit from it. In our observation in some patients, heart does not move posteriorly with DIBH and a chest wall with a rapid side-ward slope has minimal lateral expansion and less cardiac chest wall distance in DIBH with no or minimal dose reduction to the heart. These might be cases that do not benefit from DIBH. PO-201 A Prospective Study Comparing CCRT Using Paclitaxel- Carboplatin and Etoposide-Cisplatin In NSCLC S. G Y 1 1 Post Graduate Institute of Medical Education and Resear ch, Radiotherapy and oncology, Chandigarh, India Purpose or Objective Several trials as well as meta-analyses have established that the best survival can be achieved in patients with locally advanced NSCLC with concurrent CRT instead of the sequential approach. Most of the stidues used cisplatin based concurrent regime along with radiation. However, due to the higher toxicity of concurrent treatment, this is generally only given to patients with minimal or no comorbidities. In this study, we have compared different chemotherapy regime along with radiation in inoperable or non-resectable locally advanced non-metastatic NSCLC. Material and Methods In this prospective randomized study 36 patients were enrolled. The inclusion criteria was nonsmall cell lung cancer with the composite stage IIIA and IIIB. Early stage resectable and metastatic patients were excluded from the study. In study arm patients were treated with concomitant CRT using Injection cisplatin 20 mg/m 2 /day iv & days 29-33 and Injection etoposide 50 mg/m 2 /day iv days 1-5 & days 29-33 along with EBRT to a total dose of 60 Gy in 30#, starting day 1 of chemotherapy, @ 2Gy/# & 5#/week using CO-60 machine. In study arm patients were treated with concomitant chemotherapy using Injection paclitaxel 50mg/m 2 i/v and Injection carboplatin AUC2 i/v every Monday along with EBRT to a total dose of 60 Gy in Clinical:Lung