Abstract 207P
Background
Neoadjuvant systemic therapy (NAST) in breast cancer (BC) can allow less extensive surgical treatment, provides in vivo assessment of systemic treatment efficacy and enables additional post-operative systemic therapy. Data derived from clinical trials indicate that pathologic complete response (pCR) after NAST varies among BC subtypes and predicts favorable long-term outcomes. The aim of our study was to determine if these results are valid in real-world patients (pts).
Methods
We performed retrospective cohort analysis in pts with early and locally advanced (excluding inflammatory) BC consecutively treated with NAST in the period 2008–2018 at the Institute of Oncology Ljubljana. The primary goal was pCR rate. The secondary goals were disease-free (DFS) and overall survival (OS) according to the subtype and pCR. The pCR rate was analyzed using descriptive statistics, DFS and OS with the Kaplan-Meier method, comparison between groups with log-rank test.
Results
Overall, 411 pts’ data were evaluated. The median age was 47.2 years (range 22.4–78.7). The clinical size of the tumor was T1 in 27 pts (6.6%), T2 in 189 (46.0%) and T3 or higher in 195 pts (47.4%). The preoperative N stage was N0 in 94 (22.9%) and N+ in 317 (77.1%) pts. The subtypes distribution and the pCR rates are shown in table. At the median follow-up of 4.5 years, the disease recurred in 100 pts and 70 pts died. The median DFS and OS were not reached in any of the groups, the 5-year DFS and OS are shown in table. The 5-year DFS and OS were 91.2% and 98.2% in 78 patients with pCR and 65.0% and 80.4% in 333 pts without pCR (p<0.001). Table: 207P
pCR rates and 5-year DFS and OS according to the subtype in BC pts treated with NAST. HER2 – human epidermal growth factor 2 receptor, HR – hormone receptor
| pCR rate (%) | 5-year DFS (%) | 5-year OS (%) | |
| All subtypes (n=411; 100%) | 19.0 | 69.3 | 83.3 |
| Triple negative (n=78; 19.0%) | 25.6 | 62.0 | 64.5 |
| HER2+, HR- (n=47; 11.4%) | 38.3 | 74.3 | 77.3 |
| HER2+, HR+ (n=71; 17.3%) | 31.0 | 71.1 | 95.1 |
| HER2-, HR+ (n=215, 52.3%) | 8.4 | 70.5 | 87.6 |
Conclusions
The pCR rate was highest in HER2+, HR- and lowest in HER2-, HR+ subtype. Achieving pCR after NAST was associated with clinically meaningful improvements in survival outcomes in a real-world setting, regardless of BC subtype.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
A. Kovac: Honoraria (self): MSD; Honoraria (self), Travel/Accommodation/Expenses: Novartis; Travel/Accommodation/Expenses: Ipsen; Travel/Accommodation/Expenses: Pfizer; Travel/Accommodation/Expenses: Roche. K. Cankar: Travel/Accommodation/Expenses: Roche. L. Dobovisek: Travel/Accommodation/Expenses: Pfizer; Travel/Accommodation/Expenses: Roche. V. Jeric Horvat: Honoraria (self): MSD; Travel/Accommodation/Expenses: Pfizer. M. Rajer: Honoraria (institution), Advisory/Consultancy, Speaker Bureau/Expert testimony: AstraZeneca; Honoraria (institution), Advisory/Consultancy, Speaker Bureau/Expert testimony: Roche; Honoraria (institution), Advisory/Consultancy, Speaker Bureau/Expert testimony: Bristol Myers; Honoraria (institution), Advisory/Consultancy, Speaker Bureau/Expert testimony: MSD; Honoraria (institution), Advisory/Consultancy, Speaker Bureau/Expert testimony: Eli Lilly; Honoraria (institution), Advisory/Consultancy, Speaker Bureau/Expert testimony: Amgen. E. Matos: Advisory/Consultancy: AstraZeneca; Honoraria (self), Advisory/Consultancy: Lilly; Advisory/Consultancy: Pfizer; Honoraria (self), Advisory/Consultancy: Roche. S. Borstnar: Honoraria (self), Advisory/Consultancy: Amgen; Advisory/Consultancy: AstraZeneca; Honoraria (self), Advisory/Consultancy: Lilly; Honoraria (self), Advisory/Consultancy: Novartis; Honoraria (self), Advisory/Consultancy: Pfizer; Honoraria (self), Advisory/Consultancy: Roche; Honoraria (self): Krka; Honoraria (self): MSD. All other authors have declared no conflicts of interest.