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

ABSTRACT

CONTEXT Hypofractionated breast radiotherapy (RT), although convenient for patients and health care systems, could have a negative impact on normal tissues such as lung. Aims: 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. METHODS AND MATERIAL: 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.