Reply to Assoc. Prof. Kocak

We thank Kocak for the interest in our work (Kocak. Letter to the Editor Acta Oncologica 2021). We agree that BMI is a factor of importance that may influence cancer outcomes since both underweight and obesity may limit treatment options and tolerability. BMI may also be associated with other conditions such as COPD and cardiovascular disease. We used the Charlson Comorbidity Index and Performance Status score to capture comorbidity and general fitness. Ideally, BMI should also have been included in our analyses. However, individual level information on height and weight was not available in the Lung Cancer Research Database used for the purpose of our study [1]. With kind regards, Linda Willén et al.