Hemoglobin level trajectories in the early treatment period are related with survival outcomes in patients with breast cancer

Abstract

Hemoglobin (Hb) levels are reportedly related with treatment outcomes and survival in patients of breast cancer. However, the long-term change in Hb levels after treatment and the effects of Hb on survival remain unknown. This retrospective cohort study enrolled 1931 breast cancer patients with pathological stage I-IV between 1/1/2003 and 12/31/2013. Latent class modeling was used to identify trajectories in monthly Hb levels over time. The primary endpoint was 10-year cancer-related death. We identified 5 distinct Hb trajectories: persistent anemia (5.6 %; n = 109), improved anemia (4.8 %, n = 93), mild anemia (21.0%; n = 406), low normal Hb (46.6 %; n = 899), and normal Hb (21.9%; n = 424). Compared with the normal-Hb group, trajectories with low Hb levels had worst 10-year survival. The adjusted hazard ratios were 1.79(95% CI, 0.91-3.53) for the improved anemia group, 1.09(95% CI, 0.68-1.74) for the mild anemia group, 1.06 (95% CI, 0.71-1.60) for the low normal Hb group, and 2.19(95% CI 1.28-3.75) for the persistent anemia group. Our findings show there are five Hb level trajectories during breast cancer treatment. The anemia Hb level trajectory during the first 12 months after treatment reflect the worst cancer-related 10-year survival in breast cancer patients.

Keywords: breast cancer; hemoglobin; survival; trajectory.

Figure 1. Trajectory of Hb level within the first year of breast cancer

Overall Hb trajectory (1A) and distinct five Hb trajectories (1B) by group-based trajectory modeling were plotted.

Figure 2. The 10-year survival curve according to the trajectory groups

The highest mortality rate occurred for the persistent anemia group. The highest survival rate occurred for the normal Hb group. Survival curve of Kaplan-Meier analysis by Hb trajectory is shown (2A). The cumulative incidence by trajectory groups is plotted (2B).