Abstract
The impact of vitamin D levels on the progression-free survival of women with hormone receptor-positive, HER2-negative metastatic breast cancer treated with CDK4/6 inhibitors.
Author
person
Alejandro Aranda-Gutierrez
Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, Mexico
info_outline
Alejandro Aranda-Gutierrez, Andres Meraz-Brenez, Hector Raul Gonzalez-Sanchez, Haydee Cristina Verduzco-Aguirre, Bertha Alejandra Martinez-Cannon
Full text
Authors
person
Alejandro Aranda-Gutierrez
Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, Mexico
info_outline
Alejandro Aranda-Gutierrez, Andres Meraz-Brenez, Hector Raul Gonzalez-Sanchez, Haydee Cristina Verduzco-Aguirre, Bertha Alejandra Martinez-Cannon
Organizations
Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, Mexico
Abstract Disclosures
Research Funding
No funding sources reported
Background:
Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) halt the transition from the G1 to the S phase, a process governed by the hyperphosphorylation of the retinoblastoma (Rb) protein. Similarly, vitamin D3 has been demonstrated to induce cell cycle arrest through the inhibition of various cyclin-dependent kinases, including those responsible for phosphorylating the Rb protein. Therefore, we hypothesized that suboptimal vitamin D levels may compromise the efficacy of CDK4/6i used to treat hormone receptor (HR)-positive, HER2-negative metastatic breast cancer (MBC).
Methods:
We conducted a retrospective single-center study of women diagnosed with HR-positive, HER2-negative MBC and treated with any CDK4/6i between 2020 and 2023. Eligible patients were those who received at least one cycle of CDK4/6i, had a baseline 25-OH vitamin D measurement, and had a follow-up period of more than three months. Independent samples T-test, X2, and Fisher’s exact tests were used to evaluate associations between variables. Progression-free survival (PFS) was calculated using the Kaplan-Meier method and compared according to vitamin D levels using the log-rank test.
Results:
Among 31 patients, the mean age at diagnosis was 53 years (SD 14), 24 (77%) received CDK4/6i in the first-line setting, and 9 (29%) had suboptimal vitamin D levels (<20 ng/ml). Clinicopathological features based on vitamin D levels are shown (Table). The type of iCDK was different according to vitamin D levels (p = 0.036), with no other observed differences between groups. With a median follow-up of 26 months (95% CI 17-35) since iCDK initiation, median PFS was not reached for the entire cohort. A univariate analysis revealed that patients with suboptimal vitamin D levels had an inferior median PFS compared to patients with optimal levels (14 months [95%CI 4-24] vs. not reached [p=0.016]). Notably, no other parameter was associated with PFS in univariate analyses.
Conclusions:
In this cohort of Mexican patients with HR-positive, HER2-negativeMBC, suboptimal vitamin D levels adversely impacted PFS. Given the retrospective nature of this study and the limited number of patients, we emphasize the importance of studying these findings prospectively.
Vitamin D Levels
Optimal (>=20 ng/ml)
Suboptimal (<20 ng/ml)
p-
value
n
22 (71%)
9 (29%)
Age (mean + SD)
55 + 13
48 + 14
0.143
Menopausal status
Premenopausal
Postmenopausal
8 (36%)
14 (64%)
6 (67%)
3 (33%)
0.124
Disease presentation
Recurrent
De novo
14 (64%)
8 (36%)
6 (67%)
3 (33%)
0.873
# of metastatic sites
1
>=2
4 (18%)
18 (82%)
1 (11%)
8 (89%)
0.627
Type of metastasis
Non-visceral
Visceral
12 (55%)
10 (45%)
3 (33%)
6 (67%)
0.283
iCDK4/6 treatment line
First
Second
18 (82%)
4 (18%)
6 (67%)
3 (33%)
0.360
Specific iCDK4/6 used
Palbociclib
Ribociclib
Abemaciclib
14 (64%)
8 (36%)
0
9 (100%)
0
0
0.036
1 organization
6 drugs
6 targets
Drug
palbociclibDrug
ribociclibDrug
abemaciclibTarget
CDK6Target
CDK4 & 6Drug
CDK4/6iDrug
Vitamin D3