TY - JOUR
T1 - Radiation Therapy With Cyclin-Dependent Kinase 4/6 Inhibitors
T2 - A Multi-institutional Safety and Toxicity Study
AU - Al-Rashdan, Abdulla
AU - Quirk, Sarah
AU - Roumeliotis, Michael
AU - Abedin, Tasnima
AU - Amaro, Carla Paris
AU - Barbera, Lisa
AU - Lupichuk, Sasha
AU - Cao, Jeffrey Q.
N1 - Publisher Copyright:
© 2022 Elsevier Inc.
PY - 2022/11/1
Y1 - 2022/11/1
N2 - Purpose: Our purpose was to investigate radiation therapy (RT) toxicity when given with cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) compared with RT alone. Methods and Materials: We conducted a retrospective cohort study of patients with hormonal receptor-positive and human epidermal growth factor-2 negative metastatic breast cancer treated with RT at 4 cancer centers in Alberta, Canada, between 2016 and 2020. Toxicity in patients treated with RT within 30 days of initiating to discontinuing CDK4/6i (RT + CDK4/6i) was compared with toxicity of RT in CDK4/6i-naïve patients (RT alone). The primary outcome was acute grade (G) 2 or higher, nonhematological toxicity within 30 days of RT. We also explored toxicity based on the timing of RT (prior, concurrent, post) in relation to CDK4/6i. Propensity score matching was applied to create comparable cohorts. A generalized linear mixed model was used to evaluate factors associated with acute toxicity. Results: One hundred thirty-two patients (220 RT sites) in the RT + CDK4/6i and 53 patients (93 RT sites) in RT alone were eligible. The rate of acute G2 or higher nonhematological toxicity was 11.5% versus 7%, respectively (P = .439), and acute G3 or higher nonhematological toxicity was 3.7% versus 0%, respectively (P = .151). Acute toxicity in RT + CDK4/6i group was mainly observed when RT was given concurrently (67%), with most of the G3 toxicity recorded. After propensity score matching, the association of acute toxicity with RT + CDK4/6i versus RT alone was not significant on multivariable analysis (odds ratio, 3.13; 95% confidence interval, 0.74-13.2; P = .121). Conclusions: We did not observe a significant association between CDK4/6i use and acute G2 or higher nonhematological toxicity in women with metastatic breast cancer receiving palliative RT. Given the findings of G3 toxicity, caution is advised whenever CDK4/6i is given concurrently with RT.
AB - Purpose: Our purpose was to investigate radiation therapy (RT) toxicity when given with cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) compared with RT alone. Methods and Materials: We conducted a retrospective cohort study of patients with hormonal receptor-positive and human epidermal growth factor-2 negative metastatic breast cancer treated with RT at 4 cancer centers in Alberta, Canada, between 2016 and 2020. Toxicity in patients treated with RT within 30 days of initiating to discontinuing CDK4/6i (RT + CDK4/6i) was compared with toxicity of RT in CDK4/6i-naïve patients (RT alone). The primary outcome was acute grade (G) 2 or higher, nonhematological toxicity within 30 days of RT. We also explored toxicity based on the timing of RT (prior, concurrent, post) in relation to CDK4/6i. Propensity score matching was applied to create comparable cohorts. A generalized linear mixed model was used to evaluate factors associated with acute toxicity. Results: One hundred thirty-two patients (220 RT sites) in the RT + CDK4/6i and 53 patients (93 RT sites) in RT alone were eligible. The rate of acute G2 or higher nonhematological toxicity was 11.5% versus 7%, respectively (P = .439), and acute G3 or higher nonhematological toxicity was 3.7% versus 0%, respectively (P = .151). Acute toxicity in RT + CDK4/6i group was mainly observed when RT was given concurrently (67%), with most of the G3 toxicity recorded. After propensity score matching, the association of acute toxicity with RT + CDK4/6i versus RT alone was not significant on multivariable analysis (odds ratio, 3.13; 95% confidence interval, 0.74-13.2; P = .121). Conclusions: We did not observe a significant association between CDK4/6i use and acute G2 or higher nonhematological toxicity in women with metastatic breast cancer receiving palliative RT. Given the findings of G3 toxicity, caution is advised whenever CDK4/6i is given concurrently with RT.
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U2 - 10.1016/j.ijrobp.2022.07.005
DO - 10.1016/j.ijrobp.2022.07.005
M3 - Article
C2 - 35870712
AN - SCOPUS:85136480851
SN - 0360-3016
VL - 114
SP - 399
EP - 408
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 3
ER -