88: Radiotherapy for Patients with Metastatic Breast Cancer Treated with Cyclin-Dependent Kinase 4/6 Inhibitors: A Provincial Multi-Institutional Review of Safety and Toxicity

Background: Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors show promising results in metastatic breast cancer. However, an increased incidence of adverse events is remarkable. Among others, gastrointestinal (GI) involvement is of momentous impact on patients and their quality of life. Methods: Our search included PubMed, ASCO, ESMO and SABCS databases. Randomized phase II/III trials in metastatic breast cancer receiving CDK4/6 inhibitors were identified and considered relevant based on providing a sufficient safety profile on the incidence of adverse GI effects. Results: Of the 999 records initially screened for relevance, 33 articles were found relevant and 4 studies were finally eligible for meta-analysis with a total of 2007 patients. The relative risk (RR) for all-grade nausea was 1.48 [95% confidence interval (CI): 1.12–1.93, p = 0.005], vomiting was 1.74 (95% CI: 1.09–2.76, p = 0.02), decreased appetite was 1.42 (95% CI: 1.07–1.88, p = 0.02), and for diarrhea it was 1.44 (95% CI: 1.19–1.74, p = 0.0002). Meanwhile, the RR for high-grade nausea was 1.10 (95% CI: 0.29–4.13, p = 0.89), vomiting was 1.38 (95% CI: 0.25–7.75, p = 0.72), decreased appetite was 4.00 (95% CI: 0.87–18.37, p = 0.07), and high-grade diarrhea was 1.19 (95% CI: 0.44–3.21, p = 0.73). Conclusion: Selective CDK4/6 inhibitors were not associated with higher-grade GI toxicities reflecting a well-tolerated safety profile. Regarding the increase in all-grade GI toxicities, it needs further caution with addition of cytotoxic chemotherapy.

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Observational study of clinical outcomes of eribulin mesylate in metastatic breast cancer after cyclin-dependent kinase 4/6 inhibitor therapy

Future Oncology ◽

10.2217/fon-2019-0537 ◽

2019 ◽

Vol 15 (34) ◽

pp. 3935-3944 ◽

Cited By ~ 4

Author(s):

Sarah S Mougalian ◽

Bruce A Feinberg ◽

Edward Wang ◽

Karenza Alexis ◽

Debanjana Chatterjee ◽

...

Keyword(s):

Breast Cancer ◽

Metastatic Breast Cancer ◽

Clinical Outcomes ◽

Kinase Inhibitor ◽

Objective Response ◽

Metastatic Breast ◽

Progression Free Survival ◽

Cyclin Dependent Kinase ◽

Eribulin Mesylate ◽

Free Survival

Aim: To examine the effectiveness of eribulin mesylate for metastatic breast cancer post cyclin-dependent kinase inhibitor (CDKi) 4/6 therapy. Materials & methods: US community oncologists reviewed charts of patients who had received eriublin from 3 February 2015 to 31 December 2017 after prior CDKi 4/6 therapy and detailed their clinical/treatment history, clinical outcomes (lesion measurements, progression, death) and toxicity. Results: Four patient cohorts were created according to eribulin line of therapy: second line, third line, per US label and fourth line with objective response rates/clinical benefit rates of 42.2%/58.7%, 26.1%/42.3%, 26.7%/54.1% and 17.9%/46.4%, respectively. Median progression-free survival/6-month progression-free survival (79.5% of all patients censored) by cohort was: 9.7 months/77.3%, 10.3 months/71.3%, not reached/70.4% and 4.0 months/0.0%, respectively. Overall occurrence of neutropenia = 23.5%, febrile neutropenia = 1.3%, peripheral neuropathy = 10.1% and diarrhea = 11.1%. Conclusion: Clinical outcome and adverse event rates were similar to those in clinical trials and other observational studies. Longer follow-up is required to confirm these findings.

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