Incidence of Brain Metastases in Women Treated With Neoadjuvant Chemotherapy for Breast Cancer: Implications for Screening

Purpose: Patients with metastatic breast cancer may develop brain metastases. Our study identified high-risk patients to refine selection criteria for BM screening approaches. Patients: We reviewed breast cancer patients treated with neoadjuvant chemotherapy (NAC) at a single university center between 2005 and 2019. Methods: Competing risks analysis was performed with the Fine and Gray model to analyze the cumulative incidence of BM and loco-regional recurrence. Overall survival (OS) and progression-free survival (PFS) were calculated using Kaplan-Meier and log-rank tests. Multivariable analysis was performed with Cox proportional hazards regression to identify factors predictive for development of BM. Statistical significance was determined as a 2-sided P value of <.05. Results: In total, 112 patients experienced distant failure (DF) and 49 patients developed BM. Twenty patients with BM (41%) presented with symptoms requiring craniotomy +/- whole brain radiation treatment. Patients with BM were significantly more likely to have local (P < .01) and regional (P < .01) failure. On multivariable analysis, age <40 years (P = .011), presence of lung metastases (P < .0001), and residual nodal disease with >4 lymph nodes positive after NAC (P = .024) all predicted for increased likelihood of BM. Patients with these criteria had higher likelihoods of having BM (P = .013) and worse PFS (P = .044). On multivariable analysis for OS, presence of lung metastases was the most significant predictor of poor outcome (P < .0001). Conclusion: We propose a study of screening brain MRI for young (<40 years) patients with breast cancer receiving NAC and patients who develop metastatic disease post-NAC, especially those with lung involvement.