Future lung cancer risk

Published Date: 19th July 2016

Publication Authors: Ashton M, Hughes J, Mimnagh C

Background

Lung cancer continues to be the leading cause of cancer death worldwide. The disease is predominantly common among elderly patients, thus likely to be preceded or accompanied by multiple comorbid conditions. Whilst many studies have reported association between pulmonary diseases and lung cancer occurrence, the role of other chronic conditions that manifest primarily later in life are yet to be elucidated. This study describes the pattern of comorbidities among individuals in a pilot primary care lung cancer early detection study, and explores the influence of these chronic diseases on future risk of developing lung cancer.

Methods

Diagnosed medical conditions for participants in a pilot lung cancer early detection study at a UK primary care practice were obtained. Individual's 5-year absolute risk for future development of lung cancer was estimated from the LLP risk model, which has been successfully validated in three independent studies. Patients were classified as high or low risk based on a 5-year future risk threshold of 5%. Associations of comorbidity conditions with the future risk were examined using logistic regression analysis.

Results

The median age of participants was 62yrs (range=50-88yrs) and more than half were females (53%). Musculoskeletal and connective tissue disease (85.5%) and respiratory system diseases (82.6%) were the leading comorbid conditions; these were mostly dominated by rheumatism (49.8%) and acute respiratory infection (76.2%) respectively. Prior diagnosis of circulatory disease (OR=1.84, 95% CI=1.36-2.47) and malignant disease (OR=1.45, 95% CI=1.05-2.00) were statistically significantly associated with increased risk of lung cancer whilst infectious disease (OR=0.47, 95% CI=0.35-0.64) and genitourinary system diseases (OR=0.72, 95% CI=0.52-0.94) appear statistically significantly protective. Specifically, COPD (OR=1.85, 95% CI=1.33-2.60) and cardiac diseases (OR=2.57, 95% CI=1.47-3.05) diagnosed in 22% and 21% of patients respectively were significantly associated with increased future risk of lung cancer.

Conclusion

This study demonstrates strong positive relationships between circulatory diseases, cardiac diseases in particular, and COPD with future lung cancer risk. Evidence from our results supports a role for prior diagnosis of circulatory disorders such as ischaemic heart diseases in defining lung cancer high risk individuals. Thus, incorporation of objective measures of these diseases and that of COPD may improve predictions of existing lung cancer risk models. A clearer understanding of the inter-relationship between diseases is critical for developing future prevention, early detection and treatment programmes.

De Souza, NB; Raji, OY; Mimnagh, C; Hughes, J; Duffy, SW; Ashton, M; Field, JK. (2011).  Comorbidity and future lung cancer risk in a UK high risk primary care practice . Journal of Thoracic Oncology. 6 (Suppl 2), S1424-25

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