Brain metastases in breast cancer

Brain metastases are less common than bone or visceral metastases in patients with breast cancer. The overall prognosis of breast cancer patients with brain metastases remains poor, and these metastases are less responsive to systemic therapies. Brain metastasis is associated with a reduced quality of life due to progressive neurologic impairments. Recently, a trend of increased incidence of brain metastases in breast cancer has been noted. Reasons for this increased incidence include the more frequent use of sensitive detection methods such as contrast-enhanced magnetic resonance imaging and increased awareness of brain metastasis among patients and clinicians. Adjuvant and systemic therapy with drugs that have a low blood-brain barrier penetrance can lead to an increased risk of brain metastases in breast cancer patients. Molecular subtype is a predictive factor for overall survival after developing brain metastases. Patients who do not have a poor prognosis based on previously identified prognostic factors should be treated with radiation therapy to control symptoms. Whole-brain radiation therapy, stereotactic irradiation and surgery are tools for the local treatment of brain metastases. Novel molecular target therapy, including HER2-targeted therapy, has demonstrated an antitumor effect on brain metastases. In this review, we provide a practical algorithm for the treatment of breast cancer brain metastases. This review provides an overview of the incidence, risk factors, diagnosis, prognostic factors and current and potential future management strategies of breast cancer brain metastases.

Prognostic significance of pathological complete response following neoadjuvant chemotherapy for operable breast cancer

The aim of the present retrospective study was to ascertain the significance of pathological complete response (pCR) on overall survival (OS) and disease-free survival (DFS) in each disease subtype of operable breast cancer. Using a single-institution database, 90 patients were identified, who received neoadjuvant chemotherapy (NAC) for operable breast cancer and were eligible for the analysis. In total, 10 patients (11.1%) had succumbed to their diseases and 20 (22.2%) had succumbed to their diseases or exhibited recurrences. The OS of patients with triple-negative (TN) tumors was significantly lower than that of patients with other disease subtypes (P=0.016). The DFS of patients with luminal tumors was higher than that of patients with other subtypes. Survival was improved with pCR following NAC (P=0.044). Across all subtypes, patients who achieved pCR exhibited a higher DFS than patients who did not, but not significantly. pCR only improved OS and DFS in the TN disease subtype (P=0.022 and P=0.048, respectively). pCR following NAC may have prognostic value in TN breast cancer.

Gamma knife radiosurgery for brain metastases from breast cancer

Objective

The authors conducted a retrospective cohort study to determine prognostic factors and treatment outcomes of brain metastases (BM) from breast cancer (BC) after Gamma Knife radiosurgery (GKS).

Methods

Pathologic and clinical features, and outcomes were analyzed in a cohort of 62 patients with BM from BC treated by GKS. The Kaplan-Meier method, the log-rank test, and Cox's proportional hazards model were used to assess prognostic factors.

Results

Median survival after GKS was 73.0 weeks (95% confidence interval, 46.0-100.1). HER2+ [hazard ratio (HR) 0.441; p=0.045], Karnofsky performance scale (KPS) ≥70 (RR 0.416; p=0.050) and systemic chemotherapy after GKS (RR 0.282; p=0.001) were found to be a favorable prognostic factor of overall survival. Actuarial local control (LC) rate were 89.5±4.5% and 70.5±6.9% at 6 and 12 months after GKS, respectively. No prognostic factors were found to affect LC rate. Uni- and multivariate analysis revealed that the distant control (DC) rate was higher in patients with; a small number (≤3) of metastasis (HR 0.300; p=0.045), no known extracranial metastasis (p=0.013, log-rank test), or the HER2+ subtype (HR 0.267; p=0.027). Additional whole brain radiation therapy and metastasis volume were not found to be significantly associated with LC, DC, or overall survival.

Conclusion

The treatment outcomes of patients with newly diagnosed BM from BC treated with GKS could be affected primarily by intrinsic subtype, KPS, and systemic chemotherapy. Therapeutic strategy and prognosis scoring system should be individualized based on considerations of intrinsic subtype in addition to traditionally known parameters related to stereotactic radiosurgery.

Radiation therapy for brain metastases in breast cancer patients

Most randomized comparison trials (RCTs) investigating treatments for brain metastases (BM) have included BM from any origin; as a result, more than half (52.4-77.0%) of the BM in these trials originated from the lungs (mostly non-small-cell lung cancer, NSCLC), with the breasts being the origin in only 6.8-19.0% of cases. In addition, patients with poor systemic status (KPS < 70) were not included in these trials. Hence, before we can apply RCT-based information to the daily clinical treatment of BM from breast cancers, it will be crucial to differentiate the characteristics of BM originating from NSCLC and BM originating from breast cancer. Although stereotactic radiosurgery (SRS) is widely used in Japan, level-1 evidence suggests that the benefit of using SRS in addition to whole-brain radiation therapy (WBRT) has been proven only for patients with a single BM. Treatment with SRS alone, which is widely used in Japan, seems attractive because it could avoid the risk of long-term adverse effects of WBRT. However, level-1 evidence suggests that the omission of WBRT results in a high frequency of brain tumor recurrence (BTR). In an RCT between SRS-alone and SRS + WBRT conducted in Japan, we found that patients who had a single BM and no extracranial metastases had a low risk of developing BTR after initial brain management (low-risk group) compared with those who had 2 or more BM and extracranial metastases (high-risk group). In order to meet the criteria of "low-risk" BTR, patients also should have good systemic status (KPS ≧ 70). Epidemiologic data suggest that the prognosis is twice as likely to be poor in patients with BM from breast cancer (RPA III = KPS < 70) than in patients with BM from NSCLC (40 vs. 20%); in addition, the probability of brain-only metastases in patients with breast cancer is less than half that in patients with NSCLC (20-25 vs. 60-75%). Considering these findings, we should be aware that most patients with BM from breast cancer are not good candidates for SRS alone, and, therefore, the role of WBRT is still important in the era of modern radiation techniques.