Ventilatory efficiency slope as a predictor of suitability for surgery in chronic obstructive pulmonary disease patients with lung cancer

Lung cancer is one of the leading cancers with an estimated 1.8 million new cases in 2012 as per WHO estimates. Tobacco smoking is considered to be the key driver causing 70% or more of total lung cancer-related deaths worldwide (1). Lung cancer and chronic obstructive pulmonary disease (COPD) commonly coexist in smokers, and the presence of COPD increases the risk of developing lung cancer by 4–5 folds, even when the smoking history is controlled for (2). Lung cancer may consist of small cell carcinoma and non-small cell carcinomas encompassing squamous cell carcinoma, adenocarcinoma and large cell carcinoma (3). In a recent very comprehensive study by Shafiek and colleagues published in European Journal of Cardio-Thoracic Surgery, highlighted the lethal association between COPD and lung cancer and the risk of postoperative complications in these patients considered fit for surgery (4). This publication is a very timely reminder highlighting the importance of this association between COPD/lung cancer and warrants further experimental studies exploring the link between the two and complications associated. Unfortunately, the research effort directed into this has been disproportionately weak compared to its clinical and scientific importance, and indeed, COPD itself is the least researched of all common chronic conditions compared to its social significance (5,6). It is of interest and relevance in this context that up to 70% of lung cancer occurs in the context of mild-to-moderate (not severe) COPD (1,5,7-9).