High resolution computed tomography findings on the lung of early breast-cancer patients treated by postoperative breast irradiation with a hypofractionated radiotherapy schedule

BACKGROUND: Hypofractionated breast radiotherapy (RT), although convenient for patients and health care systems, could have a negative impact on normal tissues such as lung. AIM: To evaluate radiation-induced lung toxicity in early breast-cancer patients treated by hypofractionated RT. SETTINGS AND DESIGN: We have been using the 42.5 Gy/16 fractions RT schedule since May 2003. As large fraction size is related to increased normal tissue toxicity we intended to investigate the possible radiation-induced lung toxicity to these patients, by performing high-resolution computed tomography (HRCT) 6 months after the completion of the treatment. MATERIALS AND METHODS: A group of 30 consecutive early breast-cancer patients (T1-2N0M0) have been treated by the above-mentioned RT schedule, using a pair of opposing tangential fields. The impact of chemotherapy and hormonotherapy and various breast size-related parameters on HRCT lung changes were investigated. Acute skin and breast tissue reactions were also recorded. STATISTICAL ANALYSIS: used Correlation of numerical variables was investigated by Pearson correlation coefficient. Logistic regression analysis was used to investigate correlation between HRCT findings (present vs absent) with other variables. RESULTS: Minimal HRCT findings were evident in 15/30 patients. These included small septal lines, linear and subpleural opacities and to a lesser extend, focal-ground glass opacification. The HRCT findings were positively correlated only to field separation (distance between the entrance points of the tangential beams on the breast) (H.R.=1.33, 95% CI: 1.013-1.75). CONCLUSIONS: The short 16-fraction RT schedule for early breast-cancer patients appears to have a minor effect on the underlying lung parenchyma