Time interval between the diagnosis of breast cancer and brain metastases impacts prognosis after metastasis surgery.

PURPOSE: Breast cancer (BC) is the most frequently diagnosed tumor entity in women. Occurring at different time intervals (TI) after BC diagnosis, brain metastases (BM) are associated with poor prognosis. We aimed to identify the risk factors related to and the clinical impact of timing on overall survival (OS) after BM surgery. METHODS: We included 93 female patients who underwent BC BM surgery in our institution (2008-2019). Various clinical, radiographic, and histopathologic markers were analyzed with respect to TI and OS. RESULTS: The median TI was 45.0 months (range: 9-334.0 months). Fifteen individuals (16.1%) showed late occurrence of BM (TI ≥ 10 years), which was independently related to invasive lobular BC [adjusted odds ratio (aOR) 9.49, 95% confidence interval (CI) 1.47-61.39, p = 0.018] and adjuvant breast radiation (aOR 0.12, 95% CI 0.02-0.67, p = 0.016). Shorter TI (< 5 years, aOR 4.28, 95% CI 1.46-12.53, p = 0.008) was independently associated with postoperative survival and independently associated with the Union for International Cancer Control stage (UICC) III-IV of BC (aOR 4.82, 95% CI 1.10-21.17, p = 0.037), midline brain shift in preoperative imaging (aOR10.35, 95% CI 1.09-98.33, p = 0.042) and identic estrogen receptor status in BM (aOR 4.56, 95% CI 1.35-15.40, p = 0.015). CONCLUSIONS: Several factors seem to influence the period between BC and BM. Occurrence of BM within five years is independently associated with poorer prognosis after BM surgery. Patients with invasive lobular BC and without adjuvant breast radiation are more likely to develop BM after a long progression-free survival necessitating more prolonged cancer aftercare of these individuals.