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Breast cancer (BC) is the most common malignancy among women in Canada. Adjuvant treatment in early BC can reduce the risk of BC recurrence. Historically, the decision for adjuvant chemotherapy for early BC was made only based on clinical and tumour characteristics. In recent years, there has been an effort toward developing genomic assays as a predictive and prognostic tool to improve precision in estimating disease recurrence, sensitivity to systemic treatment and ultimately with clinical utility for guidance regarding adjuvant systemic treatment(s). There are various commercial genomic tests available for early-stage ER+/HER-2 negative BC. This paper will review the Oncotype DX 21-gene Recurrence Score (RS), MammaPrint, EndoPredict, Prosigna®, and Breast Cancer Index (BCI) genomic assays. We will also focus on these genomic assays' clinical application and utility in node-positive early-stage BC based on the most recent evidence and guidance recommendations. [ABSTRACT FROM AUTHOR]

Triple-negative breast cancer (TNBC) has a worse prognosis and remains the most challenging breast cancer subtype to treat. This is largely related to the heterogeneity of this disease and the lack of reliable oncological targets. In this review, we discuss the current standard-of-care treatment options for metastatic TNBC, including recent advances with the use of immunotherapy, PARP inhibitors and antibody-drug conjugates. This review also explores new agents and novel combinations arising in the field for the treatment of advanced TNBC. [ABSTRACT FROM AUTHOR]

On 15–16 June 2023, healthcare professionals and breast cancer patients and advocates from across Canada met in Toronto, Ontario, for the 2023 Canadian Breast Cancer Symposium (CBSC.). The CBSC. is a national, multidisciplinary event that occurs every 2 years with the goal of developing a personalized approach to the management of breast cancer in Canada. Experts provided state-of-the-art information to help optimally manage breast cancer patients, including etiology, prevention, diagnosis, experimental biology, and therapy of breast cancer and premalignant breast disease. The symposium also had the objectives of increasing communication and collaboration among breast cancer healthcare providers nationwide and providing a comprehensive and real-life review of the many facets of breast cancer. The sessions covered the patient voice, the top breast cancer papers from different disciplines in 2022, artificial intelligence in breast cancer, systemic therapy updates, the management of central nervous system metastases, multidisciplinary management of ductal carcinoma in situ, special populations, optimization-based individual prognostic factors, toxicity management of novel therapeutics, survivorship, and updates in surgical oncology. The key takeaways of these sessions have been summarized in this conference report. [ABSTRACT FROM AUTHOR]

Recent exciting advances in the diagnosis and management of breast cancer have improved outcomes for Canadians diagnosed and living with breast cancer. However, the reach of this progress has been uneven; disparities in accessing care across Canada are increasingly being recognized and are at risk of broadening. Members of racial minority groups, economically disadvantaged individuals, or those who live in rural or remote communities have consistently been shown to experience greater challenges in accessing 'state of the art' cancer care. The Canadian context also presents unique challenges—vast geography and provincial jurisdiction of the delivery of cancer care and drug funding create significant interprovincial differences in the patient experience. In this commentary, we review the core concepts of health equity, barriers to equitable delivery of breast cancer care, populations at risk, and recommendations for the advancement of health equity in the Canadian cancer system. [ABSTRACT FROM AUTHOR]

Background The National Surgical Adjuvant Breast and Bowel Project B-42 trial evaluated extended letrozole therapy (ELT) in postmenopausal breast cancer patients who were disease free after 5 years of aromatase inhibitor (AI)–based therapy. Seven-year results demonstrated a nonstatistically significant trend in disease-free survival (DFS) in favor of ELT. We present 10-year outcome results. Methods In this double-blind, phase III trial, patients with stage I-IIIA hormone receptor–positive breast cancer, disease free after 5 years of an AI or tamoxifen followed by an AI, were randomly assigned to 5 years of letrozole or placebo. Primary endpoint was DFS, defined as time from random assignment to breast cancer recurrence, second primary malignancy, or death. All statistical tests are 2-sided. Results Between September 2006 and January 2010, 3966 patients were randomly assigned (letrozole: 1983; placebo: 1983). Median follow-up time for 3923 patients included in efficacy analyses was 10.3 years. There was statistically significant improvement in DFS in favor of letrozole compared with placebo (hazard ratio [HR] = 0.85, 95% confidence interval [CI] = 0.74 to 0.96; P  = .01; 10-year DFS: placebo = 72.6%, letrozole = 75.9%, absolute difference = 3.3%). There was no difference in the effect of letrozole on overall survival (HR = 0.97, 95% CI = 0.82 to 1.15; P  = .74). Letrozole statistically significantly reduced breast cancer–free interval events (HR = 0.75, 95% CI = 0.62 to 0.91; P  = .003; absolute difference in cumulative incidence = 2.7%) and distant recurrences (HR = 0.72, 95% CI = 0.55 to 0.92; P  = .01; absolute difference = 1.8%). The rates of osteoporotic fractures and arterial thrombotic events did not differ between treatment groups. Conclusions The beneficial effect of ELT on DFS persisted at 10 years. Letrozole also improved breast cancer–free interval and distant recurrences without improving overall survival. Careful assessment of potential risks and benefits is necessary for selecting appropriate candidates for ELT. [ABSTRACT FROM AUTHOR]

The addition of pertuzumab to neoadjuvant trastuzumab and chemotherapy for women with early-stage, high-risk, HER2+ breast cancer has been observed to lead to higher pathologic complete response rates (pCR), and improved event-free survival compared to trastuzumab and chemotherapy alone. Based on available data, neoadjuvant pertuzumab is recommended by ESMO, ASCO, and NICE as well as by a Canadian Consensus Guideline Group. We discuss the implications for Canadian patients with HER2+ early breast cancer due to a second and final negative funding decision by the Canadian Agency for Drugs and Technologies in Health (CADTH) related to neoadjuvant pertuzumab. This decision will have adverse impacts for up to 1 in 6 women receiving neoadjuvant therapy for high-risk HER2+ breast cancer, due to suboptimal pCR rates and higher risks of invasive breast cancer recurrent events, resulting in the need for more toxic adjuvant therapy. [ABSTRACT FROM AUTHOR]

Purpose: Randomized clinical trials have shown that regional nodal irradiation (RNI) in patients with unselected N1 breast cancer improves breast cancer-specific survival. However, the benefit of RNI in women with biologically low-risk N1 breast cancer is uncertain. We conducted a population-based study to determine whether RNI is associated with improved breast cancer recurrence-free interval (BCRFI) in this population.Methods and Materials: Patients aged 40 to 79 years with pT1-2 pN1 (node-positive) breast cancer diagnosed between 2005 and 2014 were identified. The inclusion criteria were modeled off of the TAILOR RT study, which is a randomized noninferiority clinical trial designed to assess the value of RNI in patients with low-risk N1 disease. Eligible patients had breast-conserving surgery or mastectomy and axillary lymph node dissection with 1 to 3 positive nodes, breast-conserving surgery and sentinel lymph node biopsy with 1 to 2 positive nodes, or mastectomy and sentinel lymph node biopsy with 1 positive node. Additionally, patients had luminal A breast cancers, as approximated by estrogen receptor positive (Allred 6-8/8), progesterone receptor (PR) positive (Allred 6-8/8), human epidermal growth factor receptor 2-negative, and grade 1 to 2 immunohistochemical testing. All patients were prescribed hormonal treatment. The primary endpoint of BCRFI, the time to any breast cancer recurrence or breast cancer-related death, was analyzed using a multivariate competing risks analysis.Results: The cohort included 1169 women with a median follow-up of 9.2 years. Radiation treatments were not performed in 151 women treated with mastectomy alone, were delivered to the breast only in 133 women, and were delivered locoregionally in 885 women. Patients undergoing RNI were younger (median age: 58 vs 62 years), more likely to have 2 to 3 macroscopic lymph nodes involved, and more often received chemotherapy (all P < .05). The 10-year estimate of BCRFI was 90% without RNI versus 90% with RNI (P = .5). On multivariable analysis, RNI was not a significant predictor of BCRFI (hazard ratio: 1.0; P = .9).Conclusions: In this retrospective analysis, RNI was not associated with improved BCRFI for women with biologically low-risk N1 breast cancer. We advocate accrual to the ongoing TAILOR RT study. [ABSTRACT FROM AUTHOR]

Introduction: Carcinogenesis is driven by an array of complex genomic patterns; these patterns can render an individual resistant or sensitive to certain chemotherapy agents. The Personalized Oncogenomics (POG) project at BC Cancer has performed integrative genomic analysis of whole tumour genomes and transcriptomes for over 700 patients with advanced cancers, with an aim to predict therapeutic sensitivities. The aim of this study was to utilize the POG genomic data to evaluate a discrete set of biomarkers associated with chemo-sensitivity or-resistance in advanced stage breast and colorectal cancer POG patients. Methods: This was a retrospective multi-centre analysis across all BC CANCER sites. All breast and colorectal cancer patients enrolled in the POG program between July 1, 2012 and November 30, 2016 were eligible for inclusion. Within the breast cancer population, those treated with capecitabine, paclitaxel, and everolimus were analyzed, and for the colorectal cancer patients, those treated with capecitabine, bevacizumab, irinotecan, and oxaliplatin were analyzed. The expression levels of the selected biomarkers of interest (EPHB4, FIGF, CD133, DICER1, DPYD, TYMP, TYMS, TAP1, TOP1, CKDN1A, ERCC1, GSTP1, BRCA1, PTEN, ABCB1, TLE3, and TXNDC17) were reported as mRNA percentiles. Results: For the breast cancer population, there were 32 patients in the capecitabine cohort, 15 in the everolimus cohort, and 12 in the paclitaxel cohort. For the colorectal cancer population, there were 29 patients in the bevacizumab cohort, 12 in the oxaliplatin cohort, 29 in the irinotecan cohort, and 6 in the capecitabine cohort. Of the biomarkers evaluated, the strongest associations were found between Bevacizumab-based therapy and DICER1 (P = 0.0445); and between capecitabine therapy and TYMP (P = 0.0553). Conclusions: Among breast cancer patients, higher TYMP expression was associated with sensitivity to capecitabine. Among colorectal cancer patients, higher DICER1 expression was associated with sensitivity to bevacizumab-based therapy. This study supports further assessment of the potential predictive value of mRNA expression of these genomic biomarkers. [ABSTRACT FROM AUTHOR]