Lung volume changes after adjuvant breast cancer radiotherapy

s / The Breast 24 (2015) 302e307 307 References [1] JoAnna Nguyen T, Carey JN, Wong AK. J Plast ReconstrAesthet Surg. Dec 2011;64(12):1553-1561 [2] Lanier ST, Wang ED, Chen JJ, et al. Ann Plast Surg. May 2010;64(5):674678. LUNG VOLUME CHANGES AFTER ADJUVANT BREAST CANCER RADIOTHERAPY A. Pramana , L. Browne , M. Or , S. Saba , K. Pham , S. Trakis , K. Crawford , M. Hall , N. Batchelor , P. Graham . Radiation Oncology Department, St George Cancer Care Centre, Sydney, NSW, Australia; The University of New South Wales, Sydney, NSW, Australia Purpose: There is no data for lung volume changes after adjuvant breast cancer radiotherapy. Lung volume at rest and airspace volume increase with aging1. The study aim is to prospectively evaluate lung volume changes for patients who received adjuvant radiotherapy to the breast or chest wall area. Methods: Lung computed tomography (CT) was performed in 170 pa- tients at minimum period of 12 months after completion of adjuvant radiotherapy. This CT was replanned and compared with the original radiotherapy treatment plan CT images to record resting-free breathing lung volume (RFB-LV) change and to assess CT density value of various lung regions as the quantitative measurement of fibrosis2. The in-portal lung regions encompassed by the breast radiotherapy tangents were defined as central axis (CA), 5cm superior to CA, and 5cm inferior to CA. Paired t-test and regression-analysis were used to determine significance. Results: The mean age of study patients was 62 years (48-83). The mean time interval between radiotherapy start dates to study CT was 1.25 years (1-3.5). Overall, both ipsilateral and contralateral mean RFB- LV post radiotherapy were highly correlated but larger than the orig- inal values. The mean RFB-LV change were 100cc (1349 to 1449) and 212cc (1286 to 1498) for the ipsilateral and contralateral side. The degree of mean RFB-LV increase was consistently larger for contra- lateral lung. Increased CT densities in multiple ipsilateral in-portal lung regions were significantly associated with decrease in ipsilateral RFB-LV values. Conclusions: This study has indicated that RFB-LV increases post adjuvant radiotherapy. This could be explained partly due to physiological aging process or any lung pathology that cause hyper-inflation of lung volume. However, the degree of increase is less on the ipsilateral lung possibly due to increase fibrosis in the ipsilateral in-portal regions of the lung which leads to subsequent reduction of airspace volume. References [1] Sharma G, Goodwin J. Effect of aging on respiratory system physiology and immunology. Clinical Interventions in Aging (2006) 1(3): 253e260. [2] Ando K, Sekiya M, Tobino K et al. Relationship between quantitative CT metrics and pulmonary function in combined pulmonary fibrosis and emphysema. Lung (2013) 191:585e591. BILATERAL PROPHYLACTIC MASTECTOMY IN AUSTRALIA: TIME FOR A RETHINK? S. Hwang , S. Warrier , C. Mak , H. Carmalt . Department of Surgery, Prince of Wales Hospital, Randwick, NSW, Australia; Department of Breast Surgery, Royal Prince Alfred Hospital, Camperdown,