For decades, the American Society of Clinical Oncology (ASCO) Annual Meeting has been regarded as the most eminent oncology congress and a multitude of practice-changing trials reported their results at this meeting. While this has somewhat changed just recently with the European Society of Medical Oncology (ESMO) conference gaining relevance, news from the ASCO Annual Meeting is still of great clinical importance as outlined in this series of short reviews.

There is no doubt that non-small cell lung cancer (NSCLC) has been one of the most dynamic fields in oncology in recent years due to the great successes achieved with the introduction of immunotherapy concepts. The 2019 focus, however, was not on checkpoint inhibitors, but on the equally important areas of NSCLC genetics and novel small molecule drugs targeting rare and/or hard-to-target mutations and other genetic alterations as outlined by Romana Wass [1]. In contrast, no major advances in small cell lung cancer were reported, but Mircea Dediu did a great job in summarizing potentially relevant news [2].

Not surprisingly, three articles in this series are focusing on breast cancer. The article by Semir Beslija focuses on news concerning the (neo)adjuvant therapy in HER2-negative/hormone-receptor-positive breast cancer and summarizes information on prognostic and predictive biomarkers; in addition, the highly relevant—and much debated—question of extended adjuvant endocrine therapy is discussed [3].

In HER2-positive breast cancer, Marija Balic summarizes data on the potential role of neoadjuvant T‑DM1 and presents novel evidence in two further highly relevant fields: HER2 heterogeneity and its predictive role in patients receiving neoadjuvant therapy and treatment de-escalation. Indeed, the excellent survival results seen today in HER2-positive early stage breast cancer lead to the question if all patients require full-course standard chemotherapy [4]. Therefore, de-escalation is currently one of the great challenges in breast oncology. Finally, the last article focuses on new—and potentially clinically relevant—data from HER2-positive metastatic breast cancer [5].