Fig. 3: Estimated mean FACT-B total and subscale scores among all patients by age groups. Error bars indicate 95% confidence interval of the mean score at each assessment timepoint.

Mean Functional Assessment of Cancer Therapy–Breast (FACT-B) total and subscale scores over time, stratified by age group. Health-related quality of life was assessed at three time points (T1–T3). Bars represent mean scores with 95% confidence intervals. Results are shown for the overall cohort (blue) and by age group: ≤40 years (green), 41–64 years (grey), and ≥65 years (yellow). Mean FACT-B total scores increased from 113.3 at T1 to 114.3 at T2 (mean change 1.0 points; 95% CI − 1.6 to 3.5), followed by a clinically meaningful improvement to 120.6 at T3. The increase from T2 to T3 was 6.3 points (95% CI 3.7 to 8.9; effect size 0.48), with an overall improvement of 7.3 points from T1 to T3 (95% CI 4.7 to 9.8; effect size 0.47). Improvements in overall quality of life were primarily driven by gains in emotional well-being, followed by improvements in the breast cancer subscale, physical well-being, and functional well-being. Social/family well-being scores remained relatively stable across all time points. Between T1 and T2, emotional well-being improved, while functional well-being declined, resulting in minimal net change in total FACT-B scores. Between T2 and T3, functional well-being recovered to levels exceeding baseline, alongside further improvements in breast cancer-specific concerns. Similar temporal trends were observed across age groups, although absolute scores differed.