Differences in Breast Cancer Subtypes among Asian-American Women with Invasive Breast Cancer in New York City

Background: Specific breast cancer (BC) subtypes conferring distinct phenotypic and prognostic outcomes have been defined by molecular gene expression arrays. A recent study suggested that differences in BC subtypes exist among ethnic subgroups of Asian women in California. It has also been reported that there are differences in clinical outcomes among Asians with BC in the US, with Filipinos having a worse prognosis compared with other Asians. We sought to determine whether differences in BC subtypes exist among Asians in New York.Methods: Using outpatient registration records from Weill Cornell Breast Center and St. Vincent's Medical Center in New York City, we identified patients who were diagnosed with stage I, II, or III invasive BC between 1997 and 2007 who were of Chinese, Filipino, Japanese or Korean ethnicity. We reviewed pathology records according to an IRB approved protocol and recorded patient data for age, stage, grade, estrogen receptor (ER), progesterone receptor (PR) status, and HER-2/neu at diagnosis. Immunohistochemical surrogates for the four molecularly defined breast cancer subtypes were used according to accepted definitions (Luminal A: ER+Her2-; Luminal B: ER+ Her2+; Her2/neu: Her2+ ER-; Basal-like: ER-PR-, Her2-) Using chi-square analysis, we explored the relationship between ethnicity and BC subtypes.Results: 346 Asian women were identified with invasive breast cancer. Among the Chinese subgroup, 67% were of the Luminal A subtype, 15.3% were Luminal B, 10% were the Her2/neu subtype and 8.5% were Basal-like. Filipinos had a higher proportion of Luminal B cancers compared to the other ethnic groups. Filipinos and Koreans had a higher proportion of the Her2+/ER- subtype compared to Chinese and Japanese (P=0.004 by chi-square test). When considering all Her2/neu positive cancers, Filipinos had a significantly higher proportion of HER-2/neu positivity (46%) compared to Chinese (25%), Japanese (14%) and Korean (29%) groups (P=0.002). Filipinos and Koreans had a higher proportion of ER negative cancers and Grade III cancers compared to Chinese and Japanese (P=0.001 for ER status and P=0.01 for grade). In our series, Korean subjects were significantly younger than the other three ethnic groups (P<0.0001 by AVOVA test).Conclusions: Differences in BC subtypes exist among Asian women with invasive breast cancer in New York. Filipino women are significantly more likely to have HER-2/neu positive BC compared with Chinese, Japanese, and Korean women. Our results are supportive of results from a study in which differences in distribution of Her2/neu positive cancers among Asians in California were seen. Furthermore, these findings provide one explanation for the worse clinical outcome for Filipinos compared with other Asians that has been previously reported.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3067.

Phase I clinical trial of ixabepilone and pegylated liposomal doxorubicin in patients with advanced breast or ovarian cancers: New York Cancer Consortium Trial P7229

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Background: Ixabepilone (IX) is a semisynthetic epothilone B analog with activity in patients (pts) with taxane refractory cancer. Two phase III clinical trials in breast cancer (BC) and a phase II study in ovarian cancer (OC) have recently been completed. Pegylated liposomal doxorubicin (PLD) is used for the treatment of platinum refractory OC and has activity in patients with metastatic BC. Methods: We have completed enrollment of a phase I study of PLD IV and ixabepilone IV over 3 hours. 18 pts with metastatic cancer (10 BC and 8 OC) with median age 51 were enrolled from 1/13/06 to 12/22/06. A total of 60 cycles has been administered to date. 3 OC patients enrolled at dose level 3 have not yet completed 2 cycles of treatment and are not yet evaluable. Results: Dose limiting toxicities (DLT) based on toxicities experienced during the first 2 cycles is provided in the table below. Adverse events (AE) occurring in any cycle were: Grade 4 AE: neutropenia < 7 days (1 pt). Grade 3 AE: palmar plantar erythrodysesthesia (PPE) (4), mucositis (3), infection (2), fatigue (2), neutropenia (2), thrombocytopenia (2), anemia (1), neuropathy (1), bilirubin (1). Non-hematological grade 2 AEs included: mucositis (4), PPE (3), infection (2), neuropathy (2), rash (3), pain (3), fever (1), myalgias (1), and anorexia (1). Responses so far for 10 BC pts are PR (1) SD (3) PD (6) and for 5 OC pts are PR (1) SD (2) PD (2). Updated results will be presented. Conclusions: Although the recommended phase II dose when given every 3 weeks is 30 mg/m2 for PLD and 32 mg/m2 for IX by our criteria, PPE and mucositis became problematic when treatment was continued beyond 2 cycles. We are therefore exploring a 4 week PLD schedule, evaluating IX given either every 4 weeks (as shown) or weekly (on days 1, 8, and 15). A phase II trial of the combination in platinum refractory OC will be initiated upon completion of the phase I. Supported by N01-CM-62204

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