Current Challenges and Disparities in the Delivery of Equitable Breast Cancer Care in Canada.

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.

Canadian Consensus for Biomarker Testing and Treatment of TRK Fusion Cancer in Adults.

The tyrosine receptor kinase (TRK) inhibitors larotrectinib and entrectinib were recently approved in Canada for the treatment of solid tumours harbouring neurotrophic tyrosine receptor kinase (NTRK) gene fusions. These NTRK gene fusions are oncogenic drivers found in most tumour types at a low frequency (<5%), and at a higher frequency (>80%) in a small number of rare tumours (e.g., secretory carcinoma of the salivary gland and of the breast). They are generally mutually exclusive of other common oncogenic drivers. Larotrectinib and entrectinib have demonstrated impressive overall response rates and tolerability in Phase I/II trials in patients with TRK fusion cancer with no other effective treatment options. Given the low frequency of TRK fusion cancer and the heterogeneous molecular testing landscape in Canada, identifying and optimally managing such patients represents a new challenge. We provide a Canadian consensus on when and how to test for NTRK gene fusions and when to consider treatment with a TRK inhibitor. We focus on five tumour types: thyroid carcinoma, colorectal carcinoma, non-small cell lung carcinoma, soft tissue sarcoma, and salivary gland carcinoma. Based on the probability of the tumour harbouring an NTRK gene fusion, we also suggest a tumour-agnostic consensus for NTRK gene fusion testing and treatment. We recommend considering a TRK inhibitor in all patients with TRK fusion cancer with no other effective treatment options.

Positive progress: current and evolving role of immune checkpoint inhibitors in metastatic triple-negative breast cancer.

BACKGROUND: Triple-negative breast cancer (TNBC) represents an aggressive breast cancer subtype with historically poor overall outcomes, due primarily to a lack of effective targeted agents. Chemotherapy has been the primary treatment approach, although immune checkpoint inhibitors (ICIs) are currently being investigated to improve patient outcomes. This review examines the clinical implications of current evidence on the use of ICIs for the treatment of metastatic TNBC. METHODS: Our systematic search identified two phase III and five phase I/II trials reporting on the efficacy of ICIs used as monotherapy or combined with chemotherapy for the treatment of metastatic TNBC. RESULTS: The phase III IMpassion 130 trial showed a significant improvement in median progression-free survival in the intent-to-treat (net 1.7 months, p = 0.002) and PD-L1-positive populations (net 2.5 months, p < 0.001) for the addition of first-line atezolizumab versus placebo to nab-paclitaxel in metastatic TNBC. Although median overall survival was not significantly improved in patients receiving atezolizumab overall [net 2.3 months, hazard ratio (HR) 0.86, 95% confidence interval (CI) 0.72-1.02, p = 0.078], numerical improvements in the PD-L1-positive population were compelling (net 7.0 months, HR 0.71; 95% CI 0.54-0.93). Toxicity profiles were as expected, and no new safety signals were observed. Pembrolizumab monotherapy did not significantly improve overall survival in similar patients that had received prior treatment in KEYNOTE-119. CONCLUSIONS: Atezolizumab plus nab-paclitaxel represents a potential new first-line standard of care for patients with metastatic PD-L1-positive TNBC. Other ICIs used as monotherapy, or combined with chemotherapy for advanced TNBC, as well as their use for earlier stage disease, are areas of ongoing investigation.

Is knowledge translation adequate? A quality assurance study of staging investigations in early stage breast cancer patients.

After primary surgery, patients diagnosed with early stage breast cancer undergo radiological investigations based on pathologic stage of disease to rule out distant metastases. Published guidelines can aid clinicians in determining which tests are appropriate based on stage of disease. We wished to assess the consistency of radiological staging in an academic community oncology setting with standard guidelines and to determine the overall impact of non-adherence to these guidelines. A retrospective cohort study was conducted for new breast cancer patients seen at a single institution between January 2009 and April 2010. Patients were included if initial diagnosis and primary surgery was at this institution. Pathologic stage and radiological tests completed were recorded. A literature review was performed and the results were compared with those from this study to determine overall adherence rates. Subsequently, a cost analysis was performed to determine the financial impact at this centre. 231 patients met eligibility criteria for inclusion in this study. A large proportion of patients were over-staged with 129 patients (55%) undergoing unnecessary investigations according to guidelines. Specifically, 59% of stage I patients and 58% of stage II patients were over-investigated. Distant metastases at the time of diagnosis were found in three patients, all of whom had stage III disease (1.3%). The literature reviewed revealed similar non-adherence rates in other centres. The estimated cost of such non-adherence is in the range of $78 (CDN) per new early stage breast cancer patient seen at this centre. This oncology centre has a low adherence to practice guidelines for staging investigations in breast cancer patients, with 55% of patients undergoing unnecessary tests. Very few patients had metastases at diagnosis, and all had pathological stage III disease. Efforts may need to focus on improving knowledge translation across clinical oncology settings to increase guideline adherence.

A phase 2 trial exploring the effects of high-dose (10,000 IU/day) vitamin D(3) in breast cancer patients with bone metastases.

BACKGROUND: Vitamin D deficiency has potential roles in breast cancer etiology and progression. Vitamin D deficiency has also been associated with increased toxicity from bisphosphonate therapy. The optimal dose of vitamin D supplementation is unknown, but daily sunlight exposure can generate the equivalent of a 10,000-IU oral dose of vitamin D(3). This study therefore aimed to assess the effect of this dose of vitamin D(3) in patients with bone metastases from breast cancer. METHODS: Patients with bone metastases treated with bisphosphonates were enrolled into this single-arm phase 2 study. Patients received 10,000 IU of vitamin D(3) and 1000 mg of calcium supplementation each day for 4 months. The effect of this treatment on palliation, bone resorption markers, calcium metabolism, and toxicity were evaluated at baseline and monthly thereafter. RESULTS: Forty patients were enrolled. No significant changes in bone resorption markers were seen. Despite no change in global pain scales, there was a significant reduction in the number of sites of pain. A small but statistically significant increase in serum calcium was seen, as was a significant decrease in serum parathyroid hormone. Treatment unmasked 2 cases of primary hyperparathyroidism, but was not associated with direct toxicity. CONCLUSIONS: Daily doses of 10,000 IU vitamin D(3) for 4 months appear safe in patients without comorbid conditions causing hypersensitivity to vitamin D. Treatment reduced inappropriately elevated parathyroid hormone levels, presumably caused by long-term bisphosphonate use. There did not appear to be a significant palliative benefit nor any significant change in bone resorption.