Decisions regarding adjuvant chemotherapy for patients with estrogen receptor (ER)-positive, HER2-negative, lymph node-negative breast cancer have traditionally relied on clinical and pathologic parameters. However, the molecular heterogeneity and the complex tumor genome demand more sophisticated approaches to the problem. Several multigene-based assays have been developed to better prognosticate the risk of recurrence and death and predict benefit of therapy in this patient population. Oncologists are often faced with the challenge of incorporating these various complex genome-based biomarkers along with the traditional biomarkers in clinical decision-making. The NCCN Clinical Practice Guidelines in Oncology for Breast Cancer are helpful in providing a general recommendation. However, uncertainty remains in the absence of definitive data for various clinical scenarios. This case report describes a postmenopausal woman with stage I breast cancer that is low-grade and ER-rich, and has an intermediate Oncotype DX recurrence score of 28.
Noa Efrat Ben-Baruch, Ron Bose, Shyam M. Kavuri, Cynthia X. Ma, and Matthew J. Ellis
Activating mutations in the HER2 tyrosine kinase have been identified in human breast cancers that lack HER2 gene amplification. These patients are not candidates for HER2-targeted drugs under current standards of care, but preclinical data strongly suggest that these patients will benefit from anti-HER2 drugs. This case report describes a young woman with metastatic breast cancer whose tumor was found to carry a HER2 L755S mutation, which is in the kinase domain of HER2. Treatment with the second-generation HER2/EGFR tyrosine kinase inhibitor neratinib resulted in partial response and dramatic improvement in the patient's functional status. This partial response lasted 11 months, and when the patient's cancer progressed, she was treated with neratinib plus capecitabine and her cancer again responded. This second response parallels the benefit seen with continuing trastuzumab in HER2-amplified breast cancer after disease progression. This case represents the first report, to our knowledge, of successful single-agent treatment of HER2-mutated breast cancer. Two clinical trials of neratinib for HER2-mutated metastatic breast cancer are currently enrolling patients. Further, data from The Cancer Genome Atlas project have identified HER2 mutations in a wide range of solid tumors, including bladder, colorectal, and non–small cell lung cancers, suggesting that clinical trials of neratinib or neratinib-based combinations for HER2-mutated solid tumors is warranted.
Jing Xi, Aabha Oza, Shana Thomas, Foluso Ademuyiwa, Katherine Weilbaecher, Rama Suresh, Ron Bose, Mathew Cherian, Leonel Hernandez-Aya, Ashley Frith, Lindsay Peterson, Jingqin Luo, Jairam Krishnamurthy, and Cynthia X. Ma
Background: Cyclin-dependent kinase (CDK) 4/6 inhibitors are now the standard of care for hormone receptor–positive (HR+), HER2-negative (HER–) metastatic breast cancer (MBC). However, guidelines are lacking regarding their optimal sequencing with other available agents. This study examines physician practice patterns and treatment outcomes of palbociclib and subsequent therapies in a real-world setting. Methods: A retrospective chart review was conducted for consecutive patients with MBC who received palbociclib between February 2015 and August 2017 at the Alvin J. Siteman Cancer Center. Kaplan-Meier method was used to generate time-to-event curves and estimate median progression-free survival (mPFS). Log-rank test was used to compare differences. Results: A total of 200 patients, with a median age of 59.4 years and a follow-up of 19.5 months, were included. Palbociclib was most frequently combined with letrozole (73.5%), followed by fulvestrant (25%), anastrozole (1%), and tamoxifen (0.5%). Most patients received palbociclib in the endocrine-resistant setting (n=42, n=50, and n=108 in the first-, second-, and subsequent-line settings, respectively), and the fraction of patients receiving palbociclib as first- or second-line therapy increased in recent months (P=.0428). mPFS was 20.7, 12.8, and 4.0 months with palbociclib administered in the first-, second-, and subsequent-line settings, respectively (P<.0001). Incidences of grade 3/4 neutropenia (41.5%) and dose reductions (29%) were comparable to reports in the literature. Among patients whose disease progressed on palbociclib (n=104), the most frequent next-line treatment was capecitabine (n=21), followed by eribulin (n=16), nab-paclitaxel (n=15), and exemestane + everolimus (n=12). mPFS with hormone therapy alone or in combination with targeted agents (n=32) after first-, second-, and subsequent-line palbociclib was 17.0, 9.3, and 4.2 months, respectively (P=.04). mPFS with chemotherapy (n=70) was not reached, 4.7, and 4.1 months after first-, second-, and subsequent-line palbociclib, respectively (P=.56). Conclusions: Palbociclib is effective for HR+/HER2– MBC in real-world practice. Hormone therapy alone or in combination with targeted agents remains an effective option after palbociclib progression.
William R. Kennedy, Christopher Tricarico, Prashant Gabani, Ashley A. Weiner, Michael B. Altman, Laura L. Ochoa, Maria A. Thomas, Julie A. Margenthaler, Souzan Sanati, Lindsay L. Peterson, Cynthia X. Ma, Foluso O. Ademuyiwa, and Imran Zoberi
Background: Pathologic complete response (pCR) after neoadjuvant chemotherapy (NAC) for triple-negative breast cancer (TNBC) predicts decreased distant metastasis. However, most patients do not experience pCR, and other risk factors for distant metastasis after NAC are poorly characterized. This study investigated factors predictive of distant metastasis in TNBC without pCR after NAC. Methods: Women with TNBC treated with NAC, surgery, and radiation therapy in 2000 through 2013 were reviewed. Freedom from distant metastasis (FFDM) was compared between patients with and without pCR using the Kaplan-Meier method. In patients without pCR, univariate and multivariable Cox analyses were used to determine factors predictive of distant metastasis. Results: We identified 153 patients with median follow-up of 4.0 years (range, 0.5–14.0 years). After NAC, 108 had residual disease (pCR, 29%). Five-year FFDM was 98% and 55% in patients with and without pCR, respectively (P<.001). Factors independently predicting FFDM in patients without pCR were pathologic nodal positivity (hazard ratio, 3.08; 95% CI, 1.54–6.14; P=.001) and lymphovascular space invasion (hazard ratio, 1.91; 95% CI, 1.07–3.43; P=.030). Patients with a greater number of factors had worse FFDM; 5-year FFDM was 76.5% for patients with no factors (n=38) versus 54.9% and 27.5% for patients with 1 (n=44) and 2 factors (n=26), respectively (P<.001). Conclusions: Lack of pCR after NAC resulted in worse overall survival and FFDM, despite trimodality therapy. In patients with residual disease after NAC, pathologic lymph node positivity and lymphovascular space invasion predicted worse FFDM.