(ChemotherapyAdvisor) – The heart and lungs of patients treated to the left-sided breast or chest wall and locoregional lymph nodes using a monoisocentric ED conformal radiation therapy (3DCRT) with field-in-field technique were spared significantly when they used a deep inspiration breath-hold vs. a conventional free-breathing technique, a study presented at the 31st conference of the European Society for Radiotherapy and Oncology (ESTRO 31) in Barcelona, Spain, May 12 has found.
“This is the largest study to date of the use of deep inspiration breath-hold in patients undergoing radiotherapy for breast cancer,” said Dr. Amira Ziouèche from the Centre Léon Bérard, Lyon, France. “It is an important result for breast cancer patients, where it can spare the volume of heart and lungs that are irradiated. Commonly, the margins around the tumor to be treated are increased in order to take movement into account. But this involves treating a larger area, some of it unnecessarily. The use of deep inspiration breath-hold avoids this problem.”
The prospective cohort study included 31 patients with left-sided stage 2/3 breast cancer who received radiation therapy to the left-sided breast or chest wall and supraclavicular, infraclavicular, and internal mammary nodes between October 2007 and June 2010.
“Each patient was her own case-control and underwent 2 dosimetry CT scans, one in free breathing and the other one in deep inspiration breath-hold,” the investigators noted, in which patients held their breath at between 60% to 80% of maximum inspiratory. Dose volume histograms were calculated for the heart, left side and bilateral lungs, right-sided breast, and supraclavicular, infraclavicular, and internal mammary nodes, left-sided breast or chest wall clinical target volume. The primary study endpoint was heart V35, the percentage of heart receiving more than 35 Gy.
They found that when patients used deep inspiration breath-hold, all mean heart parameters were improved. Mean heart V35 value was reduced from 7.6% with free breathing to 1.1% with deep inspiration breath-hold (P<0.0001), resulting in an 85.5% absolute reduction. The average heart mean dose decreased from 9Gy to 3.7Gy and maximum dose from 44.9Gy to 24.7Gy (P<0.0001). Deep inspiration breath-hold also reduced the mean of each lung parameter. (P<0.0001).
To date, this technique is little-used in breast cancer treatment, and studies of its clinical and economic benefits demonstrating its value in breast radiation treatment are needed, they concluded.