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

Abstract

For the purpose of advanced breast cancer (ABC) guidelines, ABC comprises both inoperable locally advanced breast cancer (LABC) and metastatic breast cancer (MBC).1 , 2 Advanced/metastatic breast cancer remains a virtually incurable disease, with a median overall survival (OS) of about 3 years and a 5-year survival rate of around 25%,3 , 4 even in countries without major accessibility problems. Survival is strongly related to breast cancer subtype, with the major advances seen in human epidermal growth factor receptor 2 (HER2)-positive ABC.5, 6, 7, 8, 9 ABC is a treatable disease with several available therapies and many others in development. However, their impact on survival and quality of life (QoL) of ABC patients has been slow3 and different for de novo versus recurrent ABC, with the latter becoming much harder to treat in recent years.10 Outcomes are also strongly related to access to the best available care, which includes not only the most efficacious medicines, but also multidisciplinary, specialised care, implementation of guidelines, high-quality pathology, imaging and radiotherapy (RT). Lack of any of these crucial pillars of modern oncological care inevitably results in substantially worse outcomes, as exemplified in the New Zealand report “I am still here”.11 While mortality rates have decreased in the majority of developed countries, most deaths are currently seen in less developed societies, and access issues explain the majority of these inequalities.12 The application of the ESMO-Magnitude of Clinical Benefit Scale (ESMO-MCBS)13 to the field of ABC (P Shimon, personal communication) shows that the quality of clinical research has improved over the last decade and that better therapies have been developed, providing hope that a substantial improvement in the median OS of ABC patients might soon be seen. However, some clinically relevant questions are still unanswered and may be difficult to address through traditional clinical trials, such as the best sequence of therapies for each individual patient. The application of computer analytics to big data and real-world data is one of the potential ways forward. In-depth discussion must take place regarding the impact of this ‘new’ level of evidence (LoE) in current treatment guidelines and their integration with clinical trial data. The 5th International Consensus Conference for Advanced Breast Cancer (ABC 5) took place in Lisbon, Portugal, on 14th-16th November 2019, bringing together 1500 participants from 94 countries worldwide, including health professionals, patient advocates and journalists. Since its first edition in 2011, the main goal of the ABC conference has been the development of high-quality international consensus guidelines for the management of ABC. These guidelines are based on available evidence and on expert opinion when evidence is lacking. They represent the best management options for ABC patients globally, assuming accessibility to all available therapies. Adaptation of these guidelines is often needed in settings where access to care is suboptimal. The ABC 5 guidelines are jointly developed by ESO and ESMO, and have been endorsed by several international oncology organisations, such as the European Society of Breast Cancer Specialists (EUSOMA), European Society for Radiotherapy and Oncology (ESTRO), European Society of Gynaecological Oncology (ESGO), Union for International Cancer Control (UICC), Senologic International Society (SIS)/International School of Senology (ISS), Federacion Latino-Americana de Mastologia (FLAM), European Oncology Nursing Society (EONS), European Society of Surgical Oncology (ESSO), Arbeitsgemeinschaft Gynakologische Onkologie e.V. (AGO) and the International Society of Geriatric Oncology (SIOG), and have official representation from the American Society of Clinical Oncology (ASCO). The ABC 5 conference was also organised under the auspices of the Organisation of European Cancer Institutes (OECI) and with the support of the Breast Cancer Research Foundation (BCRF), Susan G. Komen and the ABC Global Alliance. This manuscript summarises the guidelines developed at ABC 5, each of which are accompanied by the LoE, grade of recommendation (GoR), percentage of consensus reached at the conference and supporting references. In addition, the ESMO-MCBS version 1.113 (v1.1) was used to calculate scores for new therapies/indications approved by the European Medicines Agency (EMA) since the last ABC guidelines, as well as a few new therapies that have been scored but are still under EMA evaluation (https://www.esmo.org/Guidelines/ESMO-MCBS). A table with these scores is included (see supplementary Table S1, available at https://doi/org/10.1016/j.annonc.2020.09.010).