Abstract Background: International guidelines recommend adjuvant bone-modifying agents (BMAs) for post-menopausal women with early breast cancer (EBC) to reduce recurrence and mortality. Despite this, wide variation exists internationally in the adoption of these recommendations. BMAs are off-patent with generic formulations being manufactured. Therefore, pharmaceutical lobbying for BMAs to gain regulatory approval for this indication are lacking. This may have negative impact on promotion and education of prescribing physicians, resulting in EBC patients not receiving this intervention. In the UK, BMAs were included as a recommendation in the breast cancer CRG (Clinical Reference Group) service specification and were endorsed as a priority for implementation by the UK Breast Cancer Group (UKBCG) in November 2015, promoting national uptake, local guidance and sharing of funding arrangements through local commissioning agreements. Following these, UKBCG and Breast Cancer Now, conducted 2 surveys in March and October 2016, showing that 24% and 44% respectively, of oncologists prescribe BMAs. In November 2017, a subsequent survey was performed at the annual UKBCG meeting, showed that 77% of the attendees prescribe BMAs. From 2018, BMAs are also part of the UKs NICE (National Institute for Health and Care Excellence) recommendations for EBC treatment, with the current survey to come after the full endorsement of BMAs into UK EBC guidelines. In Australia, BMAs are still ‘off-label’ and do not receive national reimbursement or endorsement. To date there has been no formal inquiry into the prescribing habits in Australia. The aim of this international collaboration was to further evaluate this and translate the methodology for adjuvant BMA implementation in the UK to Australian practice and potentially pave a pathway for other nations struggling with similar barriers to ultimately improve outcomes for women with EBC globally. Methods: Brief, anonymous, online surveys were developed at each of our institutions using a similar template. The surveys consisted of a series of questions aimed to gather data on their respective local oncologists including demographics, knowledge of current guidelines, current prescribing habits and perceived barriers to prescribing BMAs to women with EBC. The results of the UK survey and experience were used in a collaborative manner to understand the health economics and promote the deliverability of BMAs to women with EBC in Australia. Results: Between March 2019 and June 2019, the national UK survey received 67 responses from 35 centres around the UK. 98.5% of UK respondents currently prescribe adjuvant BMAs for prevention of disease recurrence. 84.6% report they follow the UKBCG guidelines on the topic and 67.7% report it is discussed in their MDTs. Between December 2018 and April 2019, 60 responses to the Australian survey were received. 48% of Australian respondents currently prescribe adjuvant BMAs for prevention of disease recurrence. However, 83% reported that they would prescribe adjuvant BMAs if funding was available. Most respondents were aware of the international guidelines on the topic but lack of local protocol guidance was seen as a significant barrier. Only 18.3% report it is discussed in their MDTs. Conclusions: From 2016 to 2019, the number of UK oncologists who prescribe BMAs has significantly increased, demonstrating that education, pressure from national bodies, national guidelines and funding decisions have been critical to implementation. Acquiring national data on this topic for Australian medical oncologists will help to address the vital need for the development of a national consensus and to clarify the financial and educational barriers that currently limit the prescription of adjuvant BMAs to women with EBC. Citation Format: Sally Baron-Hay, Elisavet Theodoulou, Isobel Porter, Caroline Wilson, Ingunn Holen, Catherine Harper-Wynne, Janet Brown. Inclusion of adjuvant bone-modifying agents for early breast cancer into standard clinical practice: Challenges and lessons learnt from an international collaboration [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-18-08.