Abstract 256P
Background
Breast cancer patients (pts) who achieve a pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) have favorable prognosis, with lower risk of distant recurrence. However, pCR after NAC may not prevent future central nervous system (CNS) metastasis (mets). We aimed to compare patterns of recurrence between pts who achieved or not pCR after NAC, looking for CNS mets as a first site of metastatic disease.
Methods
We retrospectively reviewed all breast cancer patients treated with neoadjuvant chemotherapy (2007 – 2018) in a single cancer center. Categorial variables were compared by Fisher’s exact test. Survival was estimated by the Kaplan-Maier method. Prognostic factors were adjusted by Cox regression model.
Results
602 patients were eligible, with a median age of 46 years. Most patients were premenopausal (62.5%), had histological grade II/III (85.7%), and invasive ductal carcinomas (73.8%). 394 pts had clinical stage III lesions (65.4%), most with cT4 (35.7%, n=215) and node positive (68.6%, n=413). 301 pts had luminal A or B subtype (50%), 27.1% had HER2 positive and 22.9% triple negative (TN) tumors. pCR was achieved in 177 pts (29.4%), most of them with TN (45.7% of pCR in TN) and HER2+ (51.5% of pCR in HER2+) subtype. Recurrence occurred in 16 pts (9%) with pCR and 122 pts (28.7%) with residual tumor (p<.001). Recurrences in locoregional (4 vs. 8% in non-pCR, p.01), lymph nodes (4 vs. 10.7%, p.007), lung (4.5 vs. 10.6%, p.02), liver (4.5 vs. 8.9%, p.06) and bone (4 vs. 12.7%, p.001) were all proportionally lower in pts with pCR, but this effect was not seen in CNS mets (6.2 vs. 6.4%, p 1.0). Clinical stage III (HR 3.31, CI95 1.3 – 8.5), cT4 lesions (HR 2.7, CI95 1.4 – 5.1), cN+ (HR 1.7 , CI95 1.2 – 2.3), histological grade III (HR 2.5, CI95 1.2 – 5.2) and having HER2+ or TN subtype (HR 2.0, CI95 1.0 – 3.8) increased the risk of developing CNS mets, but achieving pCR had no prognostic impact (HR 0.9, CI95 0.4 – 1.8).
Conclusions
Achieving pCR after NAC didn't prevent the occurrence of CNS mets. The CNS might be a sanctuary for micrometastatic disease that is not penetrated by current treatments available. New treatment strategies are needed for patients who achieved pCR and have additional risk factors.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.