236MO - Pathologic complete response and survival after neoadjuvant chemotherapy in stage I TNBC: A registry-based study

Background

Pathologic complete response (pCR) after neoadjuvant chemotherapy (NACT) is a strong prognosticator for survival in early triple negative breast cancer (TNBC). Chemotherapy is recommended for most patients with stage I TNBC with an increase in use in the neoadjuvant setting as recommended by the recent ESMO guidelines. However, the pCR rate after NACT and the prognostic value in stage 1 TNBC is largely unknown.

Methods

cT1N0M0 TNBC patients who received standard of care NACT followed by surgery between 2012 and 2022 were identified from the Netherlands Cancer Registry. Factors associated with pCR (ypT0/is, ypN0) and the association of pCR with overall survival (OS) were evaluated.

Results

We identified 1144 patients treated with anthracycline and taxane-based neoadjuvant chemotherapy, of whom 472 patients (41.3%) received a platinum-based regimen and 282 (24.7%) received adjuvant capecitabine. The median follow-up was 3.8 years. The majority of patients had a cT1c tumor (94.1%) and most tumors were ductal carcinomas (90.5%). A total of 656 patients (57.3%) had a pCR. Younger age (age <50 years versus ≥50 years; OR 1.75, 95% CI 1.36-2.26) and higher tumor grade (OR 2.07, 95% CI 1.55-2.76) were associated with a higher likelihood of pCR, while patients with a lobular carcinoma had a lower likelihood of having a pCR (OR 0.18, 95% CI 0.03-0.69). Platinum-based treatment was not significantly associated with improved pCR rates (57.1% versus 57.6% for patients not treated with platinum; p=0.9). Patients with a pCR had a better OS compared to patients with residual disease (HR 0.29, 95% CI 0.15-0.56), with a 4-year OS of 98% versus 93% for patients with and without a pCR respectively.

Conclusions

Data from this real-world nationwide Dutch registry on neoadjuvant chemotherapy for stage I TNBC demonstrates pCR to be associated with a favorable long-term outcome in stage 1 TNBC, supporting the use of NACT in this setting.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

S. Siesling: Non-Financial Interests, Personal, Advisory Role: Pfizer. S. Linn: Financial Interests, Institutional, Advisory Role, Advisory role + travel/accomodations/expenses: Daiichi Sankyo; Financial Interests, Institutional, Advisory Role: AstraZeneca, IBM; Non-Financial Interests, Institutional, Advisory Role: Cergentis; Financial Interests, Institutional, Research Funding: Genentech/Roche, AstraZeneca, Tesaro, Merck, Immunomedics, Eurocept Pharmaceuticals, Agendia, Novartis. M. Kok: Financial Interests, Institutional, Research Funding: BMS, Roche, AstraZeneca; Financial Interests, Institutional, Advisory Role: AstraZeneca, Daiichi Sankyo, Domain Therapeutics, Alderaan, MSD; Financial Interests, Institutional, Advisory Role, Advisory role + invited speaker: BMS, Roche; Financial Interests, Institutional, Invited Speaker: Gilead. All other authors have declared no conflicts of interest.