Adjuvant bisphosphonate use in patients with early stage breast cancer: a physician survey

Benefit of adjuvant bisphosphonates in early breast cancer treated with contemporary systemic therapy: A meta-analysis of randomized control trials

Background

The absolute and relative benefits of adjuvant bisphosphonates on disease-free survival and overall survival in patients receiving contemporary systemic therapy for early breast cancer is uncertain.

Methods

Data from randomized trials of adjuvant bisphosphonates that recruited patients exclusively after 2000 and reported disease free survival and overall survival was utilized. Five-year disease-free survival and overall survival in bisphosphonates and control group along with associated hazard ratios were extracted. Absolute data were weighted by sample size and hazard ratios were pooled using inverse variance and random effects modelling. Meta-regression comprising linear regression weighted by sample size (mixed effects) was performed to explore association between disease and treatment related factors and absolute differences in benefit from bisphosphonates.

Results

Eleven trials comprising 24023 patients were included in the analysis. For disease free survival, pooled hazard ratio was 0.89 (0.81-0.97, p = 0.008) with a 1.5 % weighted mean difference favoring bisphosphonates over control. There was no significant overall survival benefit (0.92, 0.82-1.03, p = 0.16). Among patients receiving anthracycline and taxane based chemotherapy, there were no differences in either disease free survival (0.95, 0.80-1.12) or overall survival (1.04, 0.81-1.32). Meta-regression showed lower benefits in higher risk patients (node-positive, larger tumor size, estrogen receptor-, grade 3 or those receiving chemotherapy). Overall, 1 % (95 % CI 0.75-1.15) of patients experienced osteonecrosis of jaw related to zoledronic acid.

Conclusions

Compared to the Early Breast Cancer Trialist's Collaborative Group meta-analysis, benefit from adjuvant bisphosphonates is lower in recent trials especially in higher risk patients receiving contemporary chemotherapy. The balance between benefits and risks of adjuvant bisphosphonates should be considered in individual patients.

Bone health in breast cancer

Early breast cancer is among the most common cancers worldwide. Recent advances continue to improve outcomes and increase long-term survivorship. However, therapeutic modalities are deleterious for patients' bone health. While antiresorptive therapy may partially negate this, consequent reduction in rates of fragility fractures remains unproven. Selective prescription of bisphosphonates or denosumab may be an amicable middle ground. Recent evidence also suggests a possible role of osteoclast inhibitors as adjuvant therapy, but the evidence is modest at best. In this narrative clinical review, we explore the impact of various adjuvant modalities on bone mineral density and fragility fracture rates of early breast cancer survivors. We also review optimal patient selection for antiresorptive agents, their impact on rates of fragility fractures, and the possible role of these agents as adjuvant therapy.

Use of Adjuvant Bisphosphonates and Other Bone-Modifying Agents in Breast Cancer: ASCO-OH (CCO) Guideline Update

PURPOSE

To update recommendations of the American Society of Clinical Oncology (ASCO)-Ontario Health (Cancer Care Ontario [CCO]) adjuvant bone-modifying agents in breast cancer guideline.

METHODS

An Expert Panel conducted a systematic review to identify new, potentially practice-changing data.

RESULTS

Four articles met eligibility criteria and form the evidentiary basis for revision of the previous recommendations.

RECOMMENDATIONS

Adjuvant bisphosphonate therapy should be discussed with all postmenopausal patients (natural or therapy-induced) with primary breast cancer, irrespective of hormone receptor status and human epidermal growth factor receptor 2 status, who are candidates to receive adjuvant systemic therapy. Adjuvant bisphosphonates, if used, are not substitutes for standard anticancer modalities. The benefit of adjuvant bisphosphonate therapy will vary depending on the underlying risk of recurrence and is associated with a modest improvement in overall survival. The NHS PREDICT tool provides estimates of the benefit of adjuvant bisphosphonate therapy and may aid in decision making. Factors influencing the decision to recommend adjuvant bisphosphonate use should include patients' risk of recurrence, risk of side effects, financial toxicity, drug availability, patient preferences, comorbidities, and life expectancy. When an adjuvant bisphosphonate is used to prevent breast cancer recurrence, the therapeutic options recommended by the Panel include oral clodronate, oral ibandronate, and intravenous zoledronic acid. The Panel supports starting bisphosphonate therapy early, consistent with the points outlined in the parent CCO-ASCO guideline; this is a consensus recommendation. The Panel does not recommend adjuvant denosumab to prevent breast cancer recurrence, because studies did not show a consistent reduction of breast cancer recurrence in any subset of those with early-stage breast cancer.Additional information can be found at www.asco.org/breast-cancer-guideline.

Management Strategies for Older Patients with Low-Risk Early-Stage Breast Cancer: A Physician Survey

When managing older patients with lower-risk hormone-receptor-positive (HR+), HER2 negative (HER2-) early-stage breast cancer (EBC), the harms and benefits of adjuvant therapies should be taken into consideration. A survey was conducted among Canadian oncologists on the definitions of "low risk" and "older", practice patterns, and future trial designs. We contacted 254 physicians and 21% completed the survey (50/242). Most respondents (68%, 34/50) agreed with the definition of "low risk" HR+/HER2- EBC being node-negative and either: ≤3 cm and low histological grade, ≤2 cm and intermediate grade, or ≤1 cm and high grade. The most popular chronological and biological age definition for older patients was ≥70 (45%, 22/49; 45% 21/47). In patients ≥ 70 with low risk EBC, most radiation and medical oncologists would recommend post-lumpectomy radiotherapy (RT) and endocrine therapy (ET). Seventy-eight percent (38/49) felt that trials are needed to evaluate RT and ET's role in patients ≥ 70. The favored design was ET alone, vs. RT plus ET (39%, 15/38). The preferred primary and secondary endpoints were disease-free survival and quality of life, respectively. Although oncologists recommended both RT and ET, there is interest in performing de-escalation trials in patients ≥ 70.

Adoption of adjuvant bisphosphonates for early breast cancer into standard clinical practice: Challenges and lessons learnt from comparison of the UK and Australian experience

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Adoption of adjuvant bisphosphonates for early breast cancer into standard clinical practice.

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UK and Australian experience of adjuvant bisphosphonates in early breast cancer.

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Pathway taken for adjuvant bisphosphonates implementation in the UK.

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Steps to increase update of adjuvant bisphosphonates in early breast cancer.

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Improve the care of women with early breast cancer.

International guidelines recommend adjuvant bisphosphonates (BPs) for post-menopausal women with early breast cancer to reduce recurrence and mortality. However, globally, wide variation exists in their adoption. In the UK, adjuvant BPs were a recommendation in the breast cancer Clinical Reference Group service specification and were included as a priority for implementation by the national oncologists group UK Breast Cancer Group in November 2015, promoting national uptake, guidance and funding arrangements. In 2018, adjuvant BPs were recommended by the UKs National Institute for Health and Care Excellence. In Australia, adjuvant BPs are still ‘off-label’ and do not receive national reimbursement or endorsement. To date there has been no research into the prescribing habits of these agents in Australia. With the aim to gather data on adjuvant BPs prescribing practices, online surveys were developed and disseminated to breast oncologists in both countries between December 2018 and June 2019. Almost all of the UK oncologists prescribed adjuvant BPs, demonstrating that education, endorsement from professional bodies, presence of national guidelines and funding decisions have been critical to implementation. In contrast, only 48% of the Australian responders prescribed adjuvant BPs, while 83% reported that they would prescribe them if funding was available. Lack of local protocol guidance was also seen as a major barrier. This study was intended to assess the pathway taken for adjuvant BP implementation in the UK and how it might inform changes in Australian practice and also guide other countries with similar issues with the ultimate aim of improving the care of women with early breast cancer globally.

The Rethinking Clinical Trials (REaCT) Program. A Canadian-Led Pragmatic Trials Program: Strategies for Integrating Knowledge Users into Trial Design

We reviewed patient and health care provider (HCP) surveys performed through the REaCT program. The REaCT team has performed 15 patient surveys (2298 respondents) and 13 HCP surveys (1033 respondents) that have addressed a broad range of topics in breast cancer management. Over time, the proportion of surveys distributed by paper/regular mail has fallen, with electronic distribution now the norm. For the patient surveys, the median duration of the surveys was 3 months (IQR 2.5-7 months) and the median response rate was 84% (IQR 80-91.7%). For the HCP surveys, the median survey duration was 3 months (IQR 1.75-4 months), and the median response rate, where available, was 28% (IQR 21.2-49%). The survey data have so far led to: 10 systematic reviews, 6 peer-reviewed grant applications and 19 clinical trials. Knowledge users should be an essential component of clinical research. The REaCT program has integrated surveys as a standard step of their trials process. The COVID-19 pandemic and reduced face-to-face interactions with patients in the clinic as well as the continued importance of social media highlight the need for alternative means of distributing and responding to surveys.