Abstract 288P
Background
Human epidermal growth factor-2 (HER2) low breast cancer is a novel entity that differs from HER2-negative ones. We evaluated prognostic factors in HER2 low & compared with HER2-negative breast cancer retrospectively.
Methods
Estrogen receptor (ER) +/ progesterone receptor (PR) +, HER2 low and HER2-negative patients without distant metastasis were included.
Results
444 (HL n:209, HN n:235) patients were evaluated. Median follow-up was 47 months. Most (59%) were postmenopausal. 121 (27.3%) had immunohistochemistry (IHC) score 1, 88 (19.8%) had IHC score 2 (SISH -). Mean age was 54.5 vs 53.3 years. Stage 2 (35.8%) & grade 2 (49.3%) were most common. Median ER/PR/ki67 were 95/60/25% for HER2 low & HER2 negative. 375 patients had chemotherapy, most (86%) had adjuvant chemotherapy. 40 (9%) had relapse & most (n: 31, 77.5%) had distant relapse. HER2-negative patients tended to have higher relapse rate (11.5% vs 6.2%, p:0.053). 5 year-disease free survival (DFS) was shorter for patients with HER2 negative (83.4% vs 90.8%), positive lymph nodes ≥10 (63.2% vs 92.3%), ECE + (75.4% vs 91.5%), ki67≥20% (70.2% vs 83.9%) (p: 0.021, p:0.008, p:0.004, p:0.026) (Table). Stage was inversely correlated with DFS (p: 0.001). HER2 status [HR: 0.43 (95% Cl: 0.20 –0.94), p=0.035] & ki67 [OR: 2.99 (95% Cl: 1.21–7.36), p=0.017] were significant prognostic factors in multivariate analysis. Overall survival (OS) data was immature. Table: 288P
Survival according to clinical & pathological features
| 5-year DFS (%) | Median DFS (95% CI) | p-value | 5-year OS (%) | Median OS (95% CI) | p-value | |
| Age | ||||||
| <55 | 85.5 | NR | 0.316 | 98 | NR | 0.579 |
| ≥55 | 89.7 | 128.2 (88.4-167.9) | 95.2 | NR | ||
| Menopausal status | ||||||
| Premenopausal | 89.2 | NR | 0.599 | 97.6 | NR | 0.523 |
| Postmenopausal | 85.7 | 128.2 (95.3-161.1) | 96.1 | NR | ||
| Ki67 | ||||||
| <20 | 83.9 | NR | 0.026 | 96.2 | NR | 0.441 |
| ≥20 | 70.2 | NR | 96.6 | NR | ||
| HER2 status | ||||||
| Negative | 83.4 | 121.8 (93.6-150.1) | 0.021 | 97.1 | NR | 0.214 |
| Low | 90.8 | NR | 96.7 | NR | ||
| Posivite Lymph node | ||||||
| <10 | 92.3 | 156.1 (124.3-187.9) | 0.008 | 96.6 | NR | 0.946 |
| ≥10 | 63.2 | NR | 97.2 | NR | ||
| Stage | ||||||
| Stage 1 | 99 | NR | 0.001 | 97.4 | NR | 0.463 |
| Stage 2A | 91.4 | NR | 95.2 | NR | ||
| Stage 2B | 88 | 121.8 (69.3-174.4) | 96 | NR | ||
| Stage 3 | 73.8 | 128.2 (70.3-186.1) | 97.9 | NR | ||
| ECE | ||||||
| ECE (-) | 91.5 | NR | 0.004 | 95.6 | NR | 0.714 |
| ECE (+) | 75.4 | 108.8 (40.3-177.2) | 97.9 | NR |
Conclusions
HER2 low breast cancer patients, especially with ki67 <20% had better DFS, Most patients had IHC score 1.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Clinical of Medical Oncology.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
334P - The contribution of nurses in early detection of breast cancer in Cameroon
Presenter: Ngalla Calvin
Session: Poster session 02
335P - Real-world data: Correlation of radiological and pathologic complete response after neoadjuvant treatment of breast cancer
Presenter: Katarina Cular
Session: Poster session 02
336P - Dual-mode near-infrared multispectral imaging system equipped with deep learning models improves the identification of cancer foci in breast cancer specimens
Presenter: Yueping Liu
Session: Poster session 02
337P - Comparison of fused diffusion-weighted imaging using unenhanced MRI and abbreviated post-contrast-enhanced MRI in patients with breast cancer
Presenter: Kyeyoung Lee
Session: Poster session 02