Authors’ reply Mondal et al. and Nagpal et al.

We thank Mondal et al.[1] and Nagpal et al.[2] for their critical comments on our article, “Gated radiation therapy for patients with breast cancer to reduce the dose to the lung and heart: A comparative cross-sectional study.”[3] The deep inspiratory breath-hold (DIBH) technique reduces radiation dose to the heart in patients with left-sided breast cancer. Many devices are commercially available to conduct treatment via the DIBH technique, like Real-time Position Management Gating solutions from Varian systems and Active Breath Controller (ABC) from Elekta systems. Treatment with ABC involves a mouthpiece that cannot be reused. Thus, before subjecting patients to the DIBH technique-based treatment, we trained the patients with a spirometer to assess if they could hold their breath until two balls were raised in the spirometer. Only then, eligible patients underwent the radiation planning computed tomography simulation scan. In their study, Nagpal et al. measured the cardiac distances from the chest wall as a predictor of percentage reduction in dose to the heart. Irrespective of the distances, if patients can hold their breath, they should be given the benefit of treatment with the DIBH technique rather than the free-breathing technique.[4] In their study, Ferdinand et al., observed the correlation between the heart volume and maximum heart depth in the field as a predictor of cardiac dose reduction via the DIBH technique.[5] Many studies have reported different predictors for cardiac-sparing radiation techniques worldwide. Sardaro et al.[6] estimated that a 1 Gy increase in the mean heart dose equates to a 4% increase in the risk of late heart disease, and Darby et al.[7] estimated that a 1 Gy increase in the mean heart dose causes a 7.4% increase in the rate of major coronary events, like myocardial infarction or death from ischemic heart disease. Chakraborty et al. estimated that the disability-adjusted life years averted would be 622.53 if all Indian patients with left-sided breast cancer (estimated 61,272.65/year) were treated with DIBH. The incremental cost-effectiveness ratio was $4132.90 per disability-adjusted life year, which was 2.11 times the Indian per-capita gross domestic product (2016–2017: $1957.11). Thus, Chakraborty et al. demonstrated that DIBH is cost-effective in developing nations, where cardiac illness is the most prevalent non-communicable disease.[8] Though the mean heart dose of 4.50 ± 0.96 Gy was slightly higher with DIBH in our study[3] compared to other studies, we saw a significant decrease in the mean dose of the heart compared to the free breathing technique. Nevertheless, we would like to continue to give this benefit of DIBH technique-based radiation therapy to all patients with left-sided breast cancer in our institute. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.