Luminal A Subtype Predicts Improved Survival in Patients with Metastatic Breast Carcinoma to the Brain.
Sarah E Martin, Sunil S Badve, Patricia Steeg, Eyas M Hattab. Indiana University School of Medicine, Indianapolis; National Cancer Institute, Bethesda, MD
Background: The most common central nervous system (CNS) neoplasm is metastasis from another site, with breast being the second most common primary. Breast cancer patients typically have advanced systemic disease by the time CNS involvement is manifested. Patients with triple negative primary breast cancer and those with Her2 amplification usually are at an increased risk for metastasis. However, very little is known about how to predict prognosis after the patients develop brain metastases. Currently, therapeutic options are limited with surgery generally only offered to those with solitary lesions, and prognosis is poor. We proposed that the molecular subgroup to which the breast cancer belongs, may influence the time from brain metastasis to death.
Design: We identified 59 cases of metastatic breast cancer to the CNS. Cases were evaluated for various demographic, clinical and pathologic parameters. In addition, immunohistochemistry for ER, PR, Her2, EGFR, and Ki67, and Her2 FISH analysis were performed. Tumors were divided into one of four established molecular subgroups based on ER, PR, and Her2 status—basal, intrinsic Her2, luminal A, and luminal B. Overall survival from the time of metastasis was plotted for each of the four groups using a Kaplan-Meier curve.
Results: Median overall survival for basal, intrinsic Her2, luminal A and luminal B subtypes was 9.3, 9.3, 43.7 and 17.4 months, respectively. Median overall survival for all groups combined was 16.7 months. Chi-square pairwise comparisons showed a significant difference in overall survival between the basal and luminal A subtypes (p<0.001). While there was a trend showing that luminal A cancers also do better than the intrinsic Her2 and luminal B subgroups, the difference did not reach statistical significance.
Conclusions: Patients with luminal A type breast cancers had a statistically significant increased overall survival from time of metastasis when compared to those of the basal subtype. The ability to stratify patients into prognostically significant categories is vital to tailoring treatment regimens to individual patients.
Tuesday, March 1, 2011 1:00 PM
Poster Session IV # 243, Tuesday Afternoon