Comorbidity in Patients With Small-Cell Lung Cancer: Trends and Prognostic Impact

Introduction: We evaluated the trends in the prevalence of comorbidity and its prognostic impact in a cohort of unselected patients with small-cell lung cancer (SCLC).

Patients and methods: All patients (n = 4142) diagnosed with SCLC from 1995 to 2012 were identified from the population-based Netherlands Cancer Registry in the Eindhoven region.

Results: The prevalence of comorbidity increased from 55% in 1995 to 1998 to 76% in 2011 to 2012 and multimorbidity (ie, ≥ 2 concomitant diseases) from 23% to 51%. The prevalence of a comorbidity increased with age. Among the men, hypertension, cardiac disease, and diabetes, in particular, became more common (increased from 11% to 35%, from 19% to 36%, and from 7% to 18%, respectively). In the women, the rate of pulmonary disease, hypertension, and cardiac disease increased the most (increased from 18% to 30%, from 12% to 28%, and from 11% to 24%, respectively). Multimorbidity was associated with a slightly increased hazard of death, independent of treatment in those with limited-stage SCLC (hazard ratio [HR] for ≥ 2 comorbidities vs. no comorbidities, 1.2; 95% confidence interval [CI], 1.0-1.4). The prognostic effects of multimorbidity resulted from treatment in those with extensive-stage SCLC (HR for ≥ 2 comorbidities vs. no comorbidities, final model, 1.2; 95% CI, 1.0-1.2). The prognostic impact of the specific comorbidities varied, with digestive disease reducing the hazard and cardiac disease increasing the hazard in those with limited-stage SCLC (HR for digestive disease vs. no digestive disease, 0.7 [95% CI, 0.5-0.9], and HR for cardiac vs. no cardiac disease, 1.2 [95% CI, 1.0-1.3]). Also, cardiac and cerebrovascular disease increased the hazard in those with extensive-stage SCLC (HR 1.2 [95% CI, 1.0-1.3] and HR 1.3 [95% CI, 1.1-1.6], respectively).

Conclusion: Comorbidity among patients with SCLC is very common and has been increasing. Multimorbidity was associated with a slightly increased hazard of death in those with limited-stage SCLC, independent of treatment. However, the prognostic effects in those with advanced-stage SCLC resulted from treatment. Digestive disease favorably affected survival and cardiac disease negatively affected the prognosis for those with limited-stage SCLC, and cardiac and cerebrovascular diseases had a negative prognostic effect for those with extensive-stage SCLC. With the burden of comorbidities in patients with SCLC increasing, more attention to individualized treatment approaches is needed.