Abstract 25P
Background
With the advent of novel antibody-drug conjugate (ADC), an emerging subgroup of human epidermal growth factor receptor 2 (HER2)-low breast cancer has been recognized which may take advantage from the anti-tumor activity. We took advantage of Taiwan Cancer Registry (TCR) to evaluate the clinical presentations and prognostication for HER2-low breast cancer.
Methods
HER2-low breast cancers were defined operationally with HER2 immunohistochemistry (IHC) 1+ or 2+ with a negative fluorescence in situ hybridization (FISH) while HER2-zero defined with an IHC score 0. Breast cancer index cases (n=189465) from TCR between 2007 and 2017 were reduced to 133546 sides of breast cancer per subject. Clinical features such as IHC test, stage, grade and outcomes such as relapse-free and overall survival were compared between HER2-low and HER2-zero.
Results
The safety analysis group comprised 37195 HER2-negative breast cancers, including 14288 IHC 1+, 10486 FISH-negative, 8907 IHC 0 and 3323 IHC 2+/FISH-undetermined cases. Among HER2-negative breast cancers, the proportion of HER2-low and HER2-zero was 68.9% and 31.1%, respectively, after excluding HER2 ambiguity. Overall survival was 95.7% versus 95.9% for HER2-low and HER2-zero breast cancers, which was 94.1% and 94.7% for relapse-free survival. The distributions of pathological stages from 0 to IV were 6.7%, 41.5%, 38.5%, 13.1% and 0.3% for HER2-low and were 8.5%, 42.8%, 37.5%, 11% and 0.4% for HER2-zero breast cancers. Regarding estrogen receptor (ER) and progesterone receptor (PR) status, 87.6% and 80.9% of the HER2-low cases were ER+ and PR+ while 81.9% and 74.8% of the HER2-zero patients were ER+ and PR+. High or poorly differentiated grade was reported from 23.4% of HER2-low and 25.5% of HER2-zero breast cancers. The diagnosed age was 54 versus 54.3 between HER2-low and HER2-zero breast cancers (P=0.02).
Conclusions
HER2-low status is not a prognostic marker for Taiwanese breast cancers while a slightly younger age of disease onset, less than half diagnosed with stage 0 and I, more ER and PR positivity and fewer grade III disease were observed for HER2-low phenotype compared with HER2-zero counterpart. These trivial differences distinguished HER2-low from HER2-zero spectrum among Taiwanese HER2-negative breast cancers.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
LMT.
Funding
Melissa Lee Cancer Foundation.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
204P - A radiomics strategy based on CT intra-tumoral and peritumoral regions for preoperative prediction of neoadjuvant chemoradiotherapy for esophageal cancer
Presenter: zhiyang li
Session: Poster Display
Resources:
Abstract
205TiP - IMPACT: Randomized, multicenter, phase III study evaluating the efficacy of immunotherapy (atezolizumab) plus anti-VEGF therapy (bevacizumab) in combination with transcatheter arterial chemoembolization for unresectable hepatocellular carcinoma (HCC)
Presenter: Tatsuya Yamashita
Session: Poster Display
Resources:
Abstract
206TiP - SIERRA: A phase IIIb, single-arm, multicentre study of tremelimumab plus durvalumab for first-line treatment of advanced unresectable hepatocellular carcinoma
Presenter: Stephen Chan
Session: Poster Display
Resources:
Abstract
207TiP - A two-arm randomized open-label prospective design superiority phase III clinical trial to compare the efficacy of docetaxel-oxaliplatin-capecitabine/ 5 -fluorouracil (DOC/F) followed by docetaxel versus CAPOX/mFOLFOX-7 in advanced gastric cancers
Presenter: Prabhat Bhargava
Session: Poster Display
Resources:
Abstract
212P - Mutational landscape and characteristics of ERBB2 in urothelial carcinoma
Presenter: Mingwei Li
Session: Poster Display
Resources:
Abstract
213P - Prognostic significance of absolute lymphocyte count in patients with metastatic renal cell carcinoma treated with first-line combination immunotherapies: Results from the International metastatic renal cell carcinoma database consortium (IMDC)
Presenter: Kosuke Takemura
Session: Poster Display
Resources:
Abstract
214P - Development and prospective validation of a multiplex RNA urine test for noninvasive detection and surveillance of urothelial carcinoma
Presenter: Hua Xu
Session: Poster Display
Resources:
Abstract
215P - Real-world outcomes of first-line tislelizumab plus axitinib in patients with metastatic non-clear cell renal cell carcinoma (mnccRCC)
Presenter: Pei Dong
Session: Poster Display
Resources:
Abstract
216P - Preliminary efficacy and safety results from ‘ReBirth’: A phase II study of risk-based bladder-sparing therapy for MIBC
Presenter: Yijun Shen
Session: Poster Display
Resources:
Abstract
217P - Conditional reprogramming of urine-derived bladder cancer cells: A model for precision medicine
Presenter: Yu Dong
Session: Poster Display
Resources:
Abstract