Dynamic Vitamin D Trajectories and Their Prognostic Value in Breast Cancer: A Group-Based Trajectory Modeling Study

Why It Matters

Dynamic vitamin D monitoring provides a novel, actionable biomarker that refines risk stratification and could guide personalized supplementation strategies in breast‑cancer care.

Key Takeaways

• Six vitamin D trajectories collapsed into three prognostic risk groups
• 64.9% of patients were severely deficient at diagnosis
• High‑risk trajectory linked to markedly reduced event‑free survival (p < 0.001)
• Nomogram with trajectory risk reached C‑index >0.7, surpassing traditional models
• Longitudinal vitamin D assessment could inform personalized treatment decisions

Pulse Analysis

Vitamin D has long been implicated in cancer biology, with laboratory studies suggesting anti‑proliferative and immunomodulatory effects. Epidemiologic investigations, however, have produced mixed results because most have relied on a single serum 25‑hydroxyvitamin D measurement, ignoring fluctuations that occur during therapy. In breast cancer—a disease marked by heterogeneous outcomes—recognizing this gap, researchers turned to longitudinal profiling to capture the true exposure‑response relationship. Consequently, clinicians lack guidance on whether to intervene based on vitamin D trends.

The recent retrospective cohort examined 513 women with primary invasive breast cancer, collecting vitamin D levels at baseline, mid‑treatment, and post‑treatment. Using group‑based trajectory modeling, six distinct patterns emerged and were consolidated into three risk categories: consistently sufficient, improving, and persistently deficient or worsening. Multivariable Cox analysis showed that patients in the high‑risk trajectory experienced a statistically significant drop in event‑free survival, independent of age, tumor stage, and molecular subtype. A prognostic nomogram that combined these trajectories with conventional clinicopathologic factors achieved a concordance index above 0.7, outperforming models that omit dynamic vitamin D data.

These findings position dynamic vitamin D monitoring as a practical, cost‑effective tool for refining breast‑cancer risk stratification. Clinicians could incorporate serial vitamin D testing into routine oncology visits, using the trajectory‑based risk score to identify patients who may benefit from early supplementation or more intensive surveillance. Moreover, the study’s methodological framework can be adapted to other biomarkers that change over time, expanding the precision‑medicine toolkit. Future prospective trials are needed to confirm causality and to determine whether correcting deficient trajectories translates into improved survival outcomes.