UCSF

Background

Prior comparisons of chemotherapy adverse events (AEs) by age and performance status (PS) are limited by the traditional maximum grade approach, which ignores low-grade AEs and longitudinal changes.

Materials and methods

To compare fatigue and neuropathy longitudinally by age (<65, ≥65 years) and PS (0-1, 2), we analyzed data from a large phase III trial of carboplatin and paclitaxel versus paclitaxel for advanced non-small cell lung cancer (CALGB 9730, n = 529). We performed multivariable (a) linear mixed models to estimate mean AE grade over time, (b) linear regression to estimate area under the curve (AUC), and (c) proportional hazards models to estimate the hazard ratio of developing grade ≥2 AE, as well as traditional maximum grade analyses.

Results

Older patients had on average a 0.17-point (95% confidence interval [CI], 0.00-0.34; p = .049) higher mean fatigue grade longitudinally compared with younger patients. PS 2 was associated with earlier development of grade ≥2 fatigue (hazard ratio [HR], 1.56; 95% CI, 1.07-2.27; p = .02). For neuropathy, older age was associated with earlier development of grade ≥2 neuropathy (HR, 1.41; 95% CI, 1.00-1.97; p = .049). Patients with PS 2 had a 1.30 point lower neuropathy AUC (95% CI, -2.36 to -0.25; p = .02) compared with PS 0-1. In contrast, maximum grade analyses only detected a higher percentage of older adults with grade ≥3 fatigue and neuropathy at some point during treatment.

Conclusion

Our comparison of complementary but distinct aspects of chemotherapy toxicity identified important longitudinal differences in fatigue and neuropathy by age and PS that are missed by the traditional maximum grade approach. Clinical trial identification number: NCT00003117 (CALGB 9730) IMPLICATIONS FOR PRACTICE: The traditional maximum grade approach ignores persistent low-grade adverse events (AEs) and changes over time. This toxicity over time analysis of fatigue and neuropathy during chemotherapy for advanced non-small cell lung cancer demonstrates how to use longitudinal methods to comprehensively characterize AEs over time by age and performance status (PS). We identified important longitudinal differences in fatigue and neuropathy that are missed by the maximum grade approach. This new information about how older adults and patients with PS 2 experience these toxicities longitudinally may be used clinically to improve discussions about treatment options and what to expect to inform shared decision making and symptom management.