Abstract P4-11-17: Can We Specifiy the Minimum Breast Size at Which Therapeutic Mammoplasty Should Be Considered To Mitigate Radiotherapy Toxicity in Patients Undergoing Breast Conserving Surgery for Breast Cancer?

Abstract

Abstract Background For breast cancer patients undergoing breast conserving surgery, local complications after breast radiotherapy have in the past been shown to be proportional to breast size. Therapeutic mammoplasty is an option to extend the role of breast conserving surgery. In our units, it has been used in larger breasted women undergoing breast conserving surgery to reduce the risk of local radiotherapy complications. Aim The aim of this multicentre study was to determine, with modern radiotherapy dosing schedules, if it is possible to specify a minimum bra cup size at which therapeutic mammoplasty should be considered. Methods Recurrence free breast cancer patients (at least 3 years post conservative surgery and radiotherapy) were identified from three oncology follow up clinics in the United Kingdom. 50Gy in 25 fractions over 5 weeks prescribed to the 100% isodose at the ICRU reference point, on the central outline of the breast had been a typical dosing schedule. Radiotherapy effects were graded using the Late Effects of Normal Tissue-Subjective Objective Management Analytical (LENT-SOMA) score. A score of two or above was taken as representing that the particular toxicity variable was present. The relationship between radiotherapy toxicity variables was calculated using the Pearson correlation co-efficient. Results 479 breast cancer patients were assessed. Increasing cup size correlated with oedema (Pearson correlation co-efficient r=0.30, p=<0.0001), induration (r=0.31, p=<0.0001), telangiectasia (r=0.24, p=<0.0001), breast retraction (r=0.15, p=0.002) and pain (r=0.10, p=0.030). 2.3% of patients with cup size AA/A exhibited fibrosis, 6.6% with cup size B or C, 11.8% cup size D and 25.5% with cup size DD and above. Conclusion Local radiotherapy complications following breast conserving surgery for breast cancer remain proportional to breast size even with modern radiotherapy equipment and dosing schedules. This effect is most pronounced in women with a bra cup size D and above. For these women, therapeutic mammoplasty should be considered. Further work to identify the genetic determinants of normal-tissue radiation damage is underway to optimise the surgical decision. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-11-17.