The choice of optimal therapy for ER+ HER2-metastatic breast cancer (PROMETHEUS): all-Russian analysis of physicians’ preferences – updated survey results

Cyclin-dependent kinase 4/6 inhibitors (iCDK4/6) are the generally accepted standard of care for the treatment of luminal HER2-negative metastatic breast cancer (ER+HER2- mBC). Data from randomized and observational studies have proven the high effectiveness of the combination of iCDK4/6 and endocrine therapy (ET) both in the 1st and in subsequent lines. The use of new drugs in real clinical practice is determined by a number of factors, including the awareness of doctors, their personal experience and subjective preferences, as well as financial support and availability in a particular region. To assess the frequency of prescription of CDK4/6, as well as other types of treatment in the 1st‑2nd line of therapy for ER+ HER2- mBC in real clinical practice in Russia, as well as to determine the factors and preferences of doctors influencing their choice, the National Association of Oncomammologists (NAOM) conducted a survey “Prometheus” of oncology specialists. From February 15 to August 30, 2023, a web survey of healthcare professionals who treat patients with mBC was conducted on the website anketolog.ru. An invitation to survey was sent out through the NAOM database, 112 questionnaires were received and processed. Earlier, in 2020, the “Prometheus” survey was conducted on the territory of the Russian Federation for a similar purpose. In this paper, we present the results of an updated and expanded survey and evaluate changes that have occurred over the past 3 years in actual clinical practice. The results of a 2023 survey conducted in the Russian Federation on the choice of early-line therapy for ER+HER2- mBC showed that, compared with the 2020 survey, the level of “trust” in iCDK4/6 has increased among practicing physicians, and the indications for their use have expanded, including visceral metastases (and even pending visceral crisis), the indications for prescribing chemotherapy in the 1st line have narrowed. When using monoET in the 1st line, the majority of respondents prescribe iCDK4/6 in the 2nd line. Obviously, the wider use of iCDK4/6 is associated not only with the accumulation of clinical knowledge and experience in the use of drugs, but also with improved drug supply. However, the main limitations to the use of iCDK4/6 are still insufficient funding and organizational difficulties. However, it should be noted that 1/5 of the respondents do not face any restrictions and widely prescribe combination therapy.