Clinicopathological correlation (CC) and outcome of breast cancer patients (pts) with resected brain metastasis (BM)

Abstract

656 Background: We aimed at determining the pathologic features of metastatic breast lesions to the brain, and their correlation with the primary tumor, and their effect on postneurosurgical survival (PNS). Methods: Tissue samples from 123 pts who underwent surgical resection of BM at MDACC between 1984–2004, were examined for estrogen receptor-α (ER) by IHC and HER2 by FISH or IHC. Pts’ medical records were retrospectively reviewed for CC. Results: Median (med) age at BM diagnosis was 51 years. The med time from primary diagnosis to BM was 33 months (Range (R)0–304). Infiltrating ductal cancers were found in 89%. ER was negative and HER2 amplified in 73% and 37% of BM, respectively; ER-/Her2- was seen in 43%, ER-/Her2+ in 30%, ER+/Her2+ in 6%. Concordance of ER and HER2 status between primary and BM were both 88% (p=NS, for discordance). ER positivity was associated with a longer primary diagnosis to BM interval [med 39 months (R, 0–213) vs. 29 months (R, 0–304) in the ER- pts; p=0.02]; HER2 amplification was not (p=0.82). The med PNS was 11.2 months (R, 9.0–13.5) for 112 pts with no pre- craniotomy brain radiation. Pts with ER+ metastases experienced apparent longer PNS survival than ER- pts [med 18.9 months (95% CI, 4.8–33.1) vs. 9.9 months (95% CI, 7.6–12.1 months), respectively, p=0.06], as did those with HER2-amplified BM [med 13.8 months vs. 9.9 months, respectively; p=0.10]. Pts aged 45 to <60 years had significantly longer pns survival (med 15.5 months) than younger or older pts (med 9.5 and 5.1 months, respectively), p≤.05 for all pair- wise comparisons. In mutivariate analyses correcting for age, functional status, and systemic tumor burden, neither ER nor HER2 status were independent predictors of pns. Of the 38 patients with HER2-amplified tumors and no pre- craniotomy radiation, 14 received trastuzumab (Tz) prior to initial neurosurgery. These 14 pts had longer PNS compared to those with HER2-amplified tumors not receiving Tz [median, 25.4 months vs. 10.7 months, respectively, p=NS). Conclusions: ER and HER2 positivity were highly concordant between primary and BM. Resected BM were more likely to be ER- or HER2-amplified. ER positivity and HER2 amplification were not significant independent predictors of PNS, though both showed a strong trend in univariate analyses. Middle age group pts had the best PNS survival. No significant financial relationships to disclose.