Abstract 3736
Background
For decades, conventionally fractionated whole breast irradiation (CF-WBI) was used after breast conserving surgery (BCS). Pivotal phase 3 trials on hypofractionated-WBI (HF-WBI) showed its non-inferiority as compared to CF-WBI. However, younger patients (<60 years) are not currently worldwide treated with HF-WBI. The aim of this multi-center comparative study is to confirm the safety of HF-WBI in a real-life series of younger patients.
Methods
Between 2010 and 2016, a total of 786 patients aged less than 60 years old with early stage breast cancer were treated with postoperative WBI after BCS in three breast cancer centers: 340 underwent HF-WBI while 446 were treated with CF-WBI. Acute toxicity was evaluated at the end of WBI. Late toxicity was evaluated at 6, 12, 24, and 36 months.
Results
At univariate logistic analysis, hypofractionation showed a significant protective effect in terms of acute edema (p = 0.0001), acute wet desquamation (p = 0.009), chronic edema (p = 0.0001), chronic erythema/pigmentation (p = 0.0001), and breast fibrosis (p = 0.0002). At multivariate logistic analysis, hypofractionation was independent significant factor for acute edema (OR 0.09, 95% CI 0.02 to 0.48; p = 0.005), acute wet desquamation (OR 0.07, 95% CI 0.009 to 0.59; p = 0.014), and chronic edema (OR 0.18, 95% CI 0.04 to 0.75; p = 0.018). Significant association between individual characteristics and toxicity (grade 2 or more) are summarized in Table.Table:
215P
Toxicity | N | Protective factor | p-value | OR (95%CI) | Risk factor | p-value | OR (95%CI) |
---|---|---|---|---|---|---|---|
Acute edema | 43 | Hypofractionation Dmax/Prescribed dose° <107% | 0.0001 0.001 | 0.09 (0.03-0.30) 0.16 (0.06-0.46) | Chemotherapy | 0.002 | 2.63 (1.42-4.90) |
Chronic edema | 50 | Hypofractionation Dmax/Prescribed dose° <107% | 0.0001 0.003 | 0.20 (0.09-0.44) 0.31 (0.14-0.66) | EIC presence Boost dose >10 Gy Breast size >492 cc | 0.0001 0.032 0.003 | 3.0 (1.66-5.46) 9.02 (1.21-67.45) 2.67 (1.41-5.05) |
Acute erythema/ pigmentation | 163 | HER2 positive status Trastuzumab | 0.002 0.022 | 0.30 (0.14-0.63) 0.39 (0.18-0.87) | Smoking habits Boost dose >10 Gy Breast size >492 cc | 0.001 0.038 0.002 | 2.14 (1.37-3.32) 2.60 (1.06-6.41) 1.78 (1.24-2.54) |
Chronic erythema/ pigmentation | 110 | Hypofractionation Dmax/Prescribed dose° <107% | 0.0001 0.001 | 0.40 (0.25-0.63) 0.45 (0.28-0.73) | EIC presence Positive FSM Boost dose >10 Gy Breast size >492 cc | 0.0001 0.002 0.007 0.034 | 2.39 (1.54-3.71) 3.47 (1.56-7.71) 15.43 (2.08-114.3) 1.58 (1.04-2.41) |
Acute wet desquamation | 20 | Hypofractionation Dmax/Prescribed dose° <107% | 0.009 0.047 | 0.14 (0.03-0.61) 0.29 (0.08-0.99) | - | - | - |
Breast fibrosis | 117 | Hypofractionation Tumor grade Ki67 index Dmax/Prescribed dose° <107% | 0.0002 0.022 0.023 0.017 | 0.44 (0.29-0.68) 0.53 (0.31-0.92) 0.60 (0.38-0.93) 0.58 (0.37-0.91) | EIC presence Boost dose >10 Gy Breast size >492 cc | 0.0001 0.022 0.0001 | 3.03 (1.99-4.62) 6.76 (2.04-22.45) 2.84 (1.83-4.41) |
Conclusions
HF-WBI showed significantly improved toxicity outcomes in terms of both acute skin edema and wet desquamation, and chronic skin edema. HF-WBI after BCS should replace CF-WBI independently of age.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
5792 - A novel PET parameter for cancer stem cell metabolism: early prediction of chemosensitivity to neoadjuvant chemotherapy in locally advanced breast cancer
Presenter: Chanwoo Kim
Session: Poster Display session 2
Resources:
Abstract
3728 - Using nodal ratio to predict recurrence in patients with 4 or more positive lymph nodes early stage breast cancer
Presenter: Besma Graja
Session: Poster Display session 2
Resources:
Abstract
3395 - Re-sentinel node biopsy for local recurrence after breast-conserving surgery
Presenter: Yuka Matsubara
Session: Poster Display session 2
Resources:
Abstract
4302 - Assessment of prognostic and therapeutic factors in men with breast cancer
Presenter: Daniel Herrero Rivera
Session: Poster Display session 2
Resources:
Abstract
4263 - Genomic Profiling of Chinese Breast Cancer Patients
Presenter: Zhonghua Tao
Session: Poster Display session 2
Resources:
Abstract
2406 - Genome copy number alteration burden represents predictor of response in long-term, never relapse exceptional responders of trastuzumab-treated HER2+ metastatic breast cancer
Presenter: Naomi Walsh
Session: Poster Display session 2
Resources:
Abstract
2575 - Next-generation DNA Sequencing (NGS) Results for Tumors From Phase 2 ABRAZO Study of Talazoparib After Platinum or Cytotoxic Non-Platinum Regimens in Patients (pts) With Advanced Breast Cancer (ABC) and Germline BRCA1/2 (gBRCA) Mutations
Presenter: Nicholas C. Turner
Session: Poster Display session 2
Resources:
Abstract
4499 - FGFR1 and CCND1 gene amplifications are associated with breast cancer resistance to aromatase inhibitors
Presenter: Evgeny Imyanitov
Session: Poster Display session 2
Resources:
Abstract
4110 - Clinicopathologic features of BRCA mutated breast cancer patients: Hacettepe Experience
Presenter: Sercan Aksoy
Session: Poster Display session 2
Resources:
Abstract
5203 - Novel fusion genes identified from matched primary and recurred breast cancers by RNA-sequencing
Presenter: Soojeong Choi
Session: Poster Display session 2
Resources:
Abstract