Журнал исследований рака и иммуноонкологии
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A Prospective Study of Dose Comparison between Deep Inspiratory Breath Hold (DIBH) Technique vs. Free Breathing (FB) Technique in Reducing Cardiac Dose in Left Sided Post Mastectomy Breast Cancer Patients Treated With Radiotherapy

Dev Ravishankar, Devika Sunil, Nalini Yadala, Arun Gandhi, Kirti Ranjan Mohanty

Cardiac mortality and morbidity during breast cancer treatment can be caused by both radiotherapy and chemotherapy. As chemotherapy cannot be omitted due its proven overall survival benefit, newer radiotherapy techniques like DIBH with Real-time Position Monitoring (RPM), have been devised to minimise dose to the heart without compromising target coverage. Very sparse prospective data look into the benefit of DIBH in chest wall radiotherapy. Aim: To determine dosimetrically whether DIBH reduces the cardiac (heart and left anterior descending [LAD] artery) and ipsilateral lung doses compared to FB, in patients receiving radiotherapy to left side chestwall with 3D-CRT technique and to quantify it. Material and methods: 25 consecutive left sided postmastectomy breast cancer patients with minimum breath hold duration more than 15 seconds were selected. 2 plans were made for each patient using 3D-CRT technique with a dose of 40Gy in 15 fractions- first in FB (control) and the second in DIBH with RPM system. Dose volume histograms (DVH) for each patient were generated, recorded and analysed. Results: The target coverage parameters (PTV) were found to be comparable in both plans. DIBH significantly reduced (p<0.001) the mean heart dose by 28.19% (from 5.18Gy to 3.72Gy), mean LAD dose from 25.94Gy to 16.99Gy (ie 34.50%), Maximum Heart Distance (MHD) from 2.17 cm to 1.22 cm (i.e. by 43.54%) and all heart parameters analysed. DIBH also reduced left lung V20Gy and mean lung dose and combined mean lung doses. Conclusion: With appropriate patient selection and adequate training, DIBH is an acceptable technique in reducing both cardiac and lung doses in left sided post mastectomy patients receiving radiotherapy without compromising target coverage. This could result in fewer radiotherapy-related complications even when using hypofractionated radiation doses. However, long terms follow up and studies with larger sample size are warranted in the future to consolidate the significance obtained in our study. Keywords: Breast cancer, Post-Mastectomy radiotherapy, Deep inspiratory breath hold technique, Respiratory motion management and gating, Late effects of radiation treatment, Cardiac sparing, Cardiac mortality and morbidity