PD 17 - Breast 4 -Poster Discussion
1145 - Hypofractionated Radiation is Associated With Less Long-Term Breast Retraction Following Breast Conserving Therapy
Wednesday, October 24
1:36 PM - 1:42 PM
Location: Room 217 A/B
Hypofractionated Radiation is Associated With Less Long-Term Breast Retraction Following Breast Conserving Therapy
D. Wang1,2, X. Yang3,4, J. He4, D. Mister3,4, G. Brown3,4, S. Henry3,4, J. Y. Lin Jr3,4, D. S. Yu3,4, S. T. Kahn3,4, K. D. Godette3,4, T. Liu3,4, and M. Torres3,4; 1Emory University School of Medicine, Glenn Family Breast Center, Winship Cancer Institute of Emory University, Atlanta, GA, 2Xiangya School of Medicine, Central South University, Changsha, China, 3Department of Radiation Oncology, Winship Cancer Institute of Emory University, Atlanta, GA, 4Glenn Family Breast Center, Winship Cancer Institute of Emory University, Atlanta, GA
Purpose/Objective(s): Marked breast asymmetry and retraction following breast conserving therapy is a major contributor to poor cosmetic outcome and quality of life. The goal of this prospective, longitudinal study was to determine predictors of long-term breast asymmetry in breast cancer patients treated with breast conserving surgery (BCS) and whole breast radiation (XRT).
Materials/Methods: 111 women with stage 0 to III breast cancer treated with BCS followed by conventional (50Gy plus boost) or hypofractionated (39.9Gy with simultaneous integrated boost of 48Gy) external beam XRT were enrolled on two prospective, longitudinal studies of XRT-induced skin toxicity before (baseline), during, and up to 1 year post-XRT. Using baseline and 1 year post-XRT photographs, breast asymmetry was objectively quantified by calculating the breast retraction assessment (BRA). Ultrasound images were used to objectively measure skin thickness. A skin thickness ratio (STRA) was calculated by dividing the mean skin thickness value from all four quadrants of the irradiated breast by that of the untreated breast. Univariate and multivariate analyses were conducted to determine the relationship between STRA, patient, tumor, and treatment-related factors, and BRA at baseline, 1 year post-XRT, as well as change in BRA.
Results: Among our subjects, 45% and 56% of patients had a BRA of 2 cm or more at baseline and 1 year post-XRT, respectively. Mean BRA at baseline was 2.03 cm and significantly increased to 2.83 cm at 1 year (p<0.001). Among patient, tumor, and treatment-related factors, only pre-XRT STRA associated with more baseline breast asymmetry (higher pre-XRT BRA) in multivariate analysis (p=0.04). Larger breast volume, higher baseline BRA, and conventionally fractionated (as opposed to hypofractionated) XRT were significantly associated with increased 1 year BRA in the multivariate model (all p<.001). These same factors were predictive of more severe changes in BRA in multivariate analysis (all p<.01). No other patient, tumor, or treatment related factors including age, race, smoking status, body mass index, tumor size or stage, prior chemotherapy, concurrent hormone therapy, surgical specimen size, surgical approach to the axilla, and dosimetric factors, associated with BRA at any time point or change in BRA.
Conclusion: Our prospective, longitudinal study confirms the impact of both surgery and XRT, in addition to breast volume, on objective measures of breast asymmetry. Increased breast skin thickening secondary to surgery was associated with more pre-XRT breast retraction which in turn correlated with increased post-XRT asymmetry long-term. Conventionally fractionated XRT also contributed to more breast asymmetry at 1 year than hypofractionated XRT. Our novel findings contribute to the known skin toxicity benefits of hypofractionated XRT in patients treated with breast conserving therapy.
Author Disclosure: D. Wang: None. J. He: None. D. Mister: None. G. Brown: None. K.D. Godette: None. M. Torres: Employee; Malik Smith. Research Grant; Susan G. Komen, NIH.