Lower baseline quality of life linked to 7% higher mortality risk in lung cancer patients

This systematic review and meta-analysis examined the association between baseline (pre-treatment) quality of life (QOL) and mortality in lung cancer patients. The study included 20,235 patients from 18 countries, drawing on data from multiple observational studies. The primary outcome was mortality, and the main exposure was baseline QOL assessed using various validated instruments. The comparator was not explicitly reported, as the analysis focused on the association between QOL scores and survival.

The primary analysis showed that lower baseline global QOL was associated with a statistically significant increase in mortality risk (HR = 1.07; 95% CI: 1.02-1.12). Similar associations were observed for physical, emotional, and social QOL domains, though specific effect sizes were not reported for these subdomains. Notably, cognitive QOL showed no significant association (HR = 0.99; 95% CI: 0.97-1.00), and FACT-G/FACT-L scores also showed no significant association (HR = 0.94; 95% CI: 0.80-1.09).

Safety and tolerability were not reported, as the study did not involve an intervention. The analysis did not include adverse events, serious adverse events, or discontinuations.

Compared to prior landmark studies in this therapeutic area, this meta-analysis confirms and quantifies the prognostic value of baseline QOL in lung cancer, which has been suggested in earlier individual studies. However, the substantial heterogeneity (I2 = 72-92%) across studies limits the precision of the pooled estimates. Variations in study design, QOL tools, and patient characteristics contributed to this heterogeneity. Additionally, stage-stratified estimates were rarely reported, making it difficult to assess whether the association differs by disease stage.

Key methodological limitations include the observational nature of the included studies, which precludes causal inference. The association between baseline QOL and mortality may be confounded by disease severity, comorbidities, or other unmeasured factors. The high heterogeneity also suggests that the true effect may vary across populations and settings.

Clinically, these results suggest that baseline QOL assessment may provide prognostic information beyond traditional clinical factors. However, clinicians should interpret this association cautiously and not assume that improving QOL will necessarily reduce mortality. The findings underscore the need for standardized methodologies in future research to address heterogeneity and enhance evidence quality.

Several questions remain unanswered. The mechanisms linking QOL to survival are unclear, and whether interventions that improve QOL can improve survival has not been established. Future studies should stratify by disease stage and use consistent QOL instruments to allow for more robust comparisons.