Purpose
To update the American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guideline recommendations for human epidermal growth factor receptor 2 (HER2) testing in breast cancer to improve the accuracy of HER2 testing and its utility as a predictive marker in invasive breast cancer.

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Recommendations for human epidermal growth factor receptor 2 testing in breast cancer: American Society of Clinical Oncology/College of American Pathologists clinical practice guideline update.

Purpose.—To update the American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guideline recommendations for human epidermal growth factor receptor 2 (HER2) testing in b...

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Recommendations for Human Epidermal Growth Factor Receptor 2 Testing in Breast Cancer: American Society of Clinical Oncology/College of American Pathologists Clinical Practice Guideline Update

Importance Breast cancer will be diagnosed in 12% of women in the United States over the course of their lifetimes and more than 250 000 new cases of breast cancer were diagnosed in the United States in 2017. This review focuses on current approaches and evolving strategies for local and systemic therapy of breast cancer. Observations Breast cancer is categorized into 3 major subtypes based on the presence or absence of molecular markers for estrogen or progesterone receptors and human epidermal growth factor 2 (ERBB2; formerlyHER2): hormone receptor positive/ERBB2 negative (70% of patients),ERBB2positive (15%-20%), and triple-negative (tumors lacking all 3 standard molecular markers; 15%). More than 90% of breast cancers are not metastatic at the time of diagnosis. For people presenting without metastatic disease, therapeutic goals are tumor eradication and preventing recurrence. Triple-negative breast cancer is more likely to recur than the other 2 subtypes, with 85% 5-year breast cancer–specific survival for stage I triple-negative tumors vs 94% to 99% for hormone receptor positive andERBB2positive. Systemic therapy for nonmetastatic breast cancer is determined by subtype: patients with hormone receptor–positive tumors receive endocrine therapy, and a minority receive chemotherapy as well; patients withERBB2-positive tumors receiveERBB2-targeted antibody or small-molecule inhibitor therapy combined with chemotherapy; and patients with triple-negative tumors receive chemotherapy alone. Local therapy for all patients with nonmetastatic breast cancer consists of surgical resection, with consideration of postoperative radiation if lumpectomy is performed. Increasingly, some systemic therapy is delivered before surgery. Tailoring postoperative treatment based on preoperative treatment response is under investigation. Metastatic breast cancer is treated according to subtype, with goals of prolonging life and palliating symptoms. Median overall survival for metastatic triple-negative breast cancer is approximately 1 year vs approximately 5 years for the other 2 subtypes. Conclusions and Relevance Breast cancer consists of 3 major tumor subtypes categorized according to estrogen or progesterone receptor expression andERBB2gene amplification. The 3 subtypes have distinct risk profiles and treatment strategies. Optimal therapy for each patient depends on tumor subtype, anatomic cancer stage, and patient preferences.

https://jamanetwork.com/journals/jama/articlepdf/2721183/jama_waks_2019_rv_180011.pdf

Breast Cancer Treatment: A Review.

NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines

https://minerva-access.unimelb.edu.au/bitstream/handle/11343/259112/PMC5378224.pdf

3rd ESO-ESMO International Consensus Guidelines for Advanced Breast Cancer (ABC 3)

Background Trastuzumab emtansine (T-DM1) is an antibody–drug conjugate incorporating the human epidermal growth factor receptor 2 (HER2)–targeted antitumor properties of tras tuz u mab with the cytotoxic activity of the microtubule-inhibitory agent DM1. The antibody and the cytotoxic agent are conjugated by means of a stable linker. Methods We randomly assigned patients with HER2-positive advanced breast cancer, who had previously been treated with tras tuz u mab and a taxane, to T-DM1 or la pa ti nib plus cap e ci ta bine. The primary end points were progression-free survival (as assessed by independent review), overall survival, and safety. Secondary end points included progression-free survival (investigator-assessed), the objective response rate, and the time to symptom progression. Two interim analyses of overall survival were conducted. Results Among 991 randomly assigned patients, median progression-free survival as assessed by independent review was 9.6 months with T-DM1 versus 6.4 months with la pa ti nib plus cap e ci ta bine (hazard ratio for progression or death from any cause, 0.65; 95% confidence interval [CI], 0.55 to 0.77; P<0.001), and median overall survival at the second interim analysis crossed the stopping boundary for efficacy (30.9 months vs. 25.1 months; hazard ratio for death from any cause, 0.68; 95% CI, 0.55 to 0.85; P<0.001). The objective response rate was higher with T-DM1 (43.6%, vs. 30.8% with la pa ti nib plus cap e ci ta bine; P<0.001); results for all additional secondary end points favored T-DM1. Rates of adverse events of grade 3 or above were higher with la pati nib plus cap e ci ta bine than with T-DM1 (57% vs. 41%). The incidences of thrombocytopenia and increased serum aminotransferase levels were higher with T-DM1, whereas the incidences of diarrhea, nausea, vomiting, and palmar–plantar erythro dysesthesia were higher with la pa ti nib plus cap e ci ta bine. Conclusions T-DM1 significantly prolonged progression-free and overall survival with less toxicity than la pa ti nib plus cap e ci ta bine in patients with HER2-positive advanced breast cancer previously treated with tras tuz u mab and a taxane. (Funded by F. Hoffmann– La Roche/Genentech; EMILIA ClinicalTrials.gov number, NCT00829166.)

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Do Youn Oh

Papers

Trastuzumab Emtansine for HER2-Positive Advanced Breast Cancer