Does the introduction of CDK4/6 inhibitors (CDKi) in first-line treatment of metastatic breast cancer (MBC) increase medical oncology workload?

Background: Over the last few years, the introduction of newer systemic therapies (e.g. CDKi) significantly changed the treatment paradigm of patients (pts) with MBC. The purpose of this work is to evaluate the impact of CDKi introduction in clinical practice in terms of medical oncology workload. Methods: We examined a consecutive series of 492 pts who received therapy for MBC in Academic Hospital of Udine during two historical cohorts A (2016-2017) and B (2018-2019), respectively before and after the first CDKi approval in Italy. Data about 2020 were not collected due to confounding effect of SARS-CoV-2 pandemic. Pts with no luminal MBC or enrolled in clinical trial were excluded. We performed descriptive analyses to examine any differences in terms of number and type of outpatient visits to the oncology department (i.e. planned visits, unplanned presentations and i.v. treatment sessions) between the two cohorts. Results: We analyzed a total number of 2,645 oncology activities deriving from 42 pts (cohort A) and 57 pts (cohort B) who started first line treatment for luminal MBC. Median age was 66 and 70 years respectively. In the first group, pts receiving chemotherapy were 23.8% and those treated with CDKi were 7,14%. In the second group, chemotherapy was administered in 22.8% of pts and CDKi in 49.12%. In cohort A, number of planned visits, unplanned presentations and i.v. treatment sessions were respectively 643, 82 and 418. In cohort B, number of planned visits, unplanned presentations and treatment sessions were 892, 114 and 496. During the period of observation (two years), for each pts mean number of planned visits were 15,30 (cohort A) vs 15,64 (cohort B), mean number of unplanned presentations were 1,95 (cohort A) vs 2 (cohort B), treatment i.v. sessions were 9,9 (cohort A) vs 8,7 (cohort B). Conclusions: With the limits of a retrospective analysis, no differences were found between two cohorts of pts. Notably, there was a slight decrease of i.v. treatment sessions after CDKi introduction. Other analysis are ongoing to evaluate the workload in terms of instrumental and blood chemistry tests. This data further support the handy use of this drugs into clinical practice. Legal entity responsible for the study: Azienda Sanitaria Universitaria Friuli Centrale (ASUFC) Funding: Has not received any funding. Disclosure: M. Mansutti: Financial Interests, Institutional, Advisory Board: AstraZeneca;Financial Interests, Institutional, Advisory Board, invited speaker: Novartis;Financial Interests, Institutional, Advisory Board, invited speaker: Eli Lilly;Financial Interests, Institutional, Advisory Board, invited speaker: Pfizer;Financial Interests, Institutional, Advisory Board: MSD Italia;Financial Interests, Institutional, Advisory Board, invited speaker: EISAI;Financial Interests, Institutional, Advisory Board: Pierre Fabre;Financial Interests, Institutional, Advisory Board: Roche;Financial Interests, Institutional, Advisory Board: Celgene. All other authors have declared no conflicts of interest.