Lung cancer is the leading cause of cancer death in the US, where every year more people die of it than of colon, breast and prostate cancers combined. Early diagnosis is the key to improving survival rates – usually symptoms do not appear until the disease is already in an advanced stage. Now, a new study suggests there may be a way to diagnose the disease from a blood sample.
Researchers at the Cleveland Clinic in Ohio found that patients with stage I to stage III non-small cell lung cancer – by far the most common form of the disease – have different profiles of metabolites in their blood, compared with patients who have the same risk but no disease.
Metabolites are small molecules produced from digestion and other chemical processes in the body. Individual metabolites have been used as markers of disease for years. For instance, raised glucose is used as an indicator of diabetes, and cholesterol is used as an indicator of raised risk of heart disease and stroke.
Dr. Peter J. Mazzone, a lung specialist and director of the Lung Cancer Program for the Respiratory Institute at Cleveland Clinic, says they found “patients with lung cancer have altered metabolic processes. This information could lead to the development of a diagnostic biomarker for early detection of lung cancer.”CHEST 2014
He and his colleagues examined blood samples of 284 lung cancer patients, about half men and half women, of an average age of 68 years. The patients had been diagnosed with adenocarcinoma or squamous lung cancer: 44% at stage I, 17% at stage II and 39% at stage III.
The team also studied blood samples from 194 controls with the same risk profile according to age, gender, blood lipids, smoking history, and diseases like diabetes and COPD – but who did not have lung cancer.
The researchers identified 534 metabolites common to both groups but found significant differences in concentration in 149 of them between the cancer group and the control group.
They suggest lung cancer changes metabolic processes, resulting in differences in metabolic profiles that could be developed into a diagnostic test for the disease.
The need to detect this deadly disease early was recently highlighted in a study that found lung cancer can lie dormant for 20 years.