Co-morbidity in lung cancer- important but neglected: a review of the current literature

Introduction
Treatment and survival rates for patients with lung cancer in Scotland appear lower than in many other European countries. Five-year survival is quoted at 6% to 7% compared with 8% to 15% in other European countries and America. There also appear to be variations in treatment rates within Scotland. Although this variation in treatment and survival is popularly interpreted as evidence of variation in facilities, access to care, and clinical practice, it is possible that the increased comorbidity and poor performance status of the Scottish population may contribute to the observed disparities in treatment and outcomes, although this has never been proven. The demonstration that comorbidity influences treatment and survival rates will have important implications for the targeting of health services resources, screening, interpretation of cancer statistics, and the assessment and management of patients with lung cancer.

Methods
In this article we have reviewed the tools currently available for assessing comorbidity and in addition have identified published works which study the effect of comorbidity in lung cancer.

Conclusion
There is no currently validated measurement tool applicable specifically to lung cancer and thus there remains a significant need for further work in this important area.

Statement of Search Strategies Used and Sources of Information
Literature searches were undertaken via PubMed and Google Scholar using various arrays of the following keywords: cancer, comorbidity, lung lancer, performance status, survival, and tools. The search was limited to articles published in peer-review journals with English as the language.