The Charlson Comorbidity Index plus three comorbidity scales were evaluated for survival after radiochemotherapy of limited stage SCLC. For the Charlson Comorbidity Index, 2–4 points were compared to 5–8 points. For the Age-Comorbidity Score, 2–6 points were compared to 7–10 points. For the Medical Research Council (MRC) Breathlessness Scale, grades 0–2 were compared to grades 3–5. For the Simplified Comorbidity Score, 0–5 points were compared to 6–11 and 12–17 points. Charlson Comorbidity Index (p = 0.022) and MRC Breathlessness Scale (p < 0.001) showed significant associations with survival, the Age-Comorbidity Score a trend (p = 0.06). For the Simplified Comorbidity Score, no significant correlation was found (p = 0.54). Absolute differences in survival ≥20 % were observed for the MRC Breathlessness Scale at 1, 2, and 3 years, for the Charlson Comorbidity Index at 1 year, and for the Age-Comorbidity Score at 2 years. Thus, particularly the MRC Breathlessness Scale can contribute to personalization of the treatment of SCLC.