9: The Impact of Presenting Stage on Overall Survival in Patients Treated with Neoadjuvant Chemotherapy in Triple Negative Breast Cancer

We identified 11,967 patients with pCR following NAC. Median follow-up was 4.0 years; 10-year OS estimate was 89% and varied by presenting cT category and cN status.  cT3-T4,N+ disease had poorest OS (79% at 10 years). OS was similar for cT3-T4,N0 versus cT0-T2,N+ (87% vs 88%, p=0.85), but both groups had poorer OS than cT1-T2,N0 (91%, p< 0.001).  On multivariable analysis adjusted hazard ratios (aHR) were 3.7 for cT3-T4,N+, 1.8 for cT3-T4,N0 and 1.8 for cT0-T2,N+ each compared to cT1-T2,N0 (each p< 0.001), and there remained no significant difference between cT3-T4,N0 versus cT0-2,N+ (aHR 1.0, p=0.99). 

We identified 23,631 patients with RD following NAC.  Median follow-up was 3.8 years; 10-year OS estimate was 60%, which was significantly lower than for patients with pCR (p< 0.001). OS varied by presenting cT category and cN status in a similar pattern as seen in patients with pCR (see Figure). In patients with RD, OS was best for cT1-2,N0 disease (73% at 10 years), compared to cT0-2,N+ disease (57%), cT3-4,N0 disease (55%), cT3-4,N+ disease (40%).   

Notably, OS did not differ significantly between patients with RD who presented as cT1-2,N0 and patients with pCR who presented with cT3-4,N+ disease (aHR 1.1, p=0.16). 



Conclusions: Our study shows that among TNBC patients with a pCR and those with residual disease, extent of disease at presentation further stratifies patient OS. If these findings are validated in other datasets, this would support future investigation of adjuvant systemic therapy escalation for patients with advanced disease stage at presentation who achieve a pCR, who are currently excluded from ongoing clinical trials of adjuvant therapy escalation.