New research confirms need for lung cancer testing

Different kinds of lung cancer behave in different ways, suggesting they are fundamentally different diseases. According to a University of Colorado Cancer Center study published in Cancer, the official journal of the American Cancer Society, different subgroups of non-small cell lung cancer (NSCLC) show distinct patterns of spread in the body.

The study looked at 209 patients diagnosed with stage IV non-small cell lung cancer separated into four different molecular subgroups using testing performed by the University of Colorado Molecular Correlates Laboratory (CMOCO): those with epidermal growth factor receptor (EGFR) mutations, v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations, anaplastic lymphoma receptor tyrosine kinase (ALK) gene rearrangements or a group without any of these abnormalities.

ALK positive lung cancer was strongly associated with cancers that spread to the linings around the heart and lungs (pericardial and pleural disease). Patients with ALK positive NSCLC were also predisposed to develop liver metastases as were those with an EGFR mutation when the different subgroups were compared.

"In the last few years we have been able to separate lung cancer into different molecular subtypes to help improve outcomes from specific targeted therapies. This study really confirms that these molecular subtypes are manifesting as different diseases in patients," said Robert Doebele, MD, PhD, lead author of the study and CU Cancer Center investigator.

Another University of Colorado study published in the same edition of Cancer drills down on how some of these different molecular subtypes of lung cancer are detected in the first place. Specifically, the study examined the companion diagnostic test for detecting the ALK positive lung cancer cases, called a fluorescence in situ hybridization (FISH) test. This test is used to select patients for treatment with crizotinib, an ALK inhibitor drug. Now University of Colorado researchers have solved an unanswered question as to why patients who respond to crizotinib only appear to have the ALK change in a fraction of the cells in their cancers.

Tests to diagnose lung cancer If there's reason to think that you may have lung cancer, your doctor can order a number of tests to look for cancerous cells and to rule out other conditions. In order to diagnose lung cancer, your doctor may recommend:

• Imaging tests. An X-ray image of your lungs may reveal an abnormal mass or nodule. A CT scan can reveal small lesions in your lungs that might not be detected on an X-ray.
• Sputum cytology. If you have a cough and are producing sputum, looking at the sputum under the microscope can sometimes reveal the presence of lung cancer cells.
• Tissue sample (biopsy). A sample of abnormal cells may be removed in a procedure called a biopsy. Your doctor can perform a biopsy in a number of ways, including bronchoscopy, in which your doctor examines abnormal areas of your lungs using a lighted tube that's passed down your throat and into your lungs; mediastinoscopy, in which an incision is made at the base of your neck and surgical tools are inserted behind your breastbone to take tissue samples from lymph nodes; and needle biopsy, in which your doctor uses X-ray or CT images to guide a needle through your chest wall and into the lung tissue to collect suspicious cells. A biopsy sample may also be taken from lymph nodes or other areas where cancer has spread, such as your liver.