gms | German Medical Science

Objective: Breast cancer (BC) is the most common cancer in women. Routinely, patients are followed up for 10 years, but there is a subgroup of patients with brain metastasis (BM) occurring after this follow up period. We therefore sought to assess the clinical characteristics and prognosis between patients with BM during (≤10 years) and after (>10 years) the routine follow-up period.

Methods: All patients with BM of BC that were treated in our department from January 2008 to December 2018 were eligible for our study. Patients’ records were analysed regarding age, receptor status, location of BM, histological subtype of BC, receptor conversion, extracranial metastasis, adjuvant therapies and overall survival (OS). Statistical analyses were carried out using SPSS version 25. Categorical data was analysed using chi-square test and for continuous data the Mann-Whitney-U test was applied. Survival analysis was conducted with Kaplan-Meier analysis and log-rank test.

Results: 72 patients were included into our study. 58 patients experienced BM during 10 years (group 1) after diagnosis whereas 14 patients (group 2) had very late BM (>10 years). Patients in group 2 were significantly younger at the time of first diagnosis of BC than patients in group 1 (p=0.007) and presented more frequently with multiple BM (p=0.010). However, there was no significant difference regarding age at BM diagnosis and BM location between both groups. Invasive lobular BC was significantly more frequent in group 2 (p=0.010) and patients in group 2 showed significantly more often a receptor conversion (p=0.035). When analysing the different receptors, we detected a significant difference between both groups for HER2 receptor conversion (p=0.001) but not for progesterone (p=0.641) or estrogene receptor conversion (p=0.059). There was a significant difference in OS after diagnosis of BC (p=0.0001), but not after the occurrence of BM (p=0.730). For both groups, we found a better survival for patients with identic HER2 receptor status.

Conclusion: In our patients’ cohort we identified a subgroup of patients with very late BM. These patients are characterized by a younger age at diagnosis of BC, have more frequently an invasive lobular BC, multiple BM and frequent receptor conversion, especially for HER2 receptor status. In both groups, a better survival was found for patients with identic HER2 receptor status.