Stage IV Lung Cancer With ALK Rearrangement

Some cancers, such as stage IV cancers (metastatic cancer that has progressed to other organs), may have mutations or changes, such as rearrangements, in their genes. For example, the ALK (anaplastic lymphoma kinase) gene codes for a protein that is important for cell growth and division. Changes in the gene for this protein occur in a subset of non-small cell lung cancers. This gene can be translocated to form an abnormal gene (or fusion gene), and the patient is referred to as having an "ALK positive" tumor; these tumors are highly sensitive to therapy with targeted inhibitor drugs (see below).

A number of both genetic and environmental (asbestos, smoking, radon) factors are known to cause lung cancer, although the precise mechanism is not clear. Patients with non-small cell lung cancers that harbor the ALK fusion oncogene are more likely to have never smoked or to be a light smoker than the average patient with lung cancer. In one study database of 255 patients with ALK rearrangements, never smokers and former smokers comprised 70% and 28% of cases, respectively. ALK rearrangements are found in about 3%-7% of lung cancers and tend to occur in younger individuals.

The symptoms and signs of stage IV lung cancer with ALK are essentially the same as those for non-small cell lung cancers. Symptoms and signs include

• cough,
• difficulty breathing,
• spitting or coughing blood,
• chest pain,
• hoarseness, or
• problems swallowing.

Symptoms and signs of widespread (metastatic) disease can include headaches or seizures, bone pain, and weight loss.

Genetic testing for the ALK mutation (rearrangement) is recommended for any patients diagnosed with non-small cell lung cancer.

therapy is used in treating stage IV on cancer with ALK rearrangement. Drugs such as crizotinib (Xalkori), ceritinib (Zykadia), and alectinib (Alecensa) have been developed to target the activity (lung cancer cell growth) of the abnormal fusion protein. Interference with the abnormal fusion protein does not allow cancer cells to divide and multiply very well; this treatment may prolong a patient's life span. The targeted therapy can be used in conjunction with other treatments, depending upon your physician's treatment protocols.