Generally, survival rates for ALK-positive lung cancer are better than those of non-small cell lung cancer overall.
Anaplastic lymphoma kinase or ALK mutation is a genetic alteration of the lung cells’ DNA that causes the cells to grow abnormally and eventually become cancerous. When the cancer cells begin to grow in the lungs, they can potentially spread to other parts of the body and impair its function.
ALK-positive lung cancer represents about four to five percent of all lung cancers, generally appearing in adenocarcinoma of non-small cell lung cancer. ALK-positive lung cancer usually responds well to a targeted medication called ALK inhibitors, chemotherapy and other treatments. However, cancer can recur after treatment. The survival rate of a person with ALK-positive lung cancer depends on the stage of cancer and age of the patient. Those with advanced cancer usually lived for an average of about seven years after diagnosis.
Patients who are ALK-positive tend to be younger than the average lung cancer patient. They also tend not to have a smoking history. Among the many different mutations that can drive cancer to grow, the ALK mutation is one of the more treatable types because it often responds dramatically to targeted therapy.
What causes ALK lung cancer?
Anaplastic lymphoma kinase (ALK) was originally described in lymphoma, but most ALK-positive cancers are non-small cell lung cancer. The ALK gene helps develop the gut and nervous systems and gets turned off in the womb. For some people, it can get turned back on and combine with another gene (EML4 gene). This gene change is called an ALK fusion, which can cause cancer.
When ALK fuses or joins with another gene and causes lung cancer, the gene rearrangements and fusion that occurs cause oncogenic (cancer-forming) activity. Patients with ALK rearrangements tend to be light smokers or never-smokers.
What are the signs and symptoms of ALK lung cancer?
Symptoms might not appear until cancer has spread from the lungs to other parts of the body.
The symptoms of anaplastic lymphoma kinase (ALK)-positive lung cancer are similar to other types of lung cancer, including:
- A cough that doesn’t go away
- Chest pain that gets worse when you cough, breathe deeply or laugh
- Shortness of breath
- A hoarse voice
- Wheezing
- Losing weight without trying
- Feeling weak or tired
How is ALK lung cancer diagnosed?
The doctor details your medical history and performs a complete physical assessment of you. To confirm if the lung cancer is anaplastic lymphoma kinase (ALK)-positive, there are several different tests the doctor would advise, such as:
- Fluorescence in situ hybridization (FISH) analysis: This test is used to detect changes in the chromosomes by studying the tissues under a microscope.
- Immunohistochemistry: Detects defective proteins in the cells under a microscope.
- Next-generation sequencing (massively parallel sequencing): This technique utilizes deoxyribonucleic acid (DNA) sequencing technologies that are capable of processing multiple DNA sequences in parallel.
- Liquid biopsy: This tests for cancer DNA in the blood.
How is ALK lung cancer treated?
Once confirmed that the lung cancer tests positive for the anaplastic lymphoma kinase (ALK) mutation, there are many treatment options in addition to targeted therapy. If the lung cancer has not yet spread and it’s at an early stage, surgery is recommended to remove the lung cancer completely. If not, there are drugs called “ALK inhibitors” that target the ALK+ mutation and stop cancer from growing and spreading.
Other treatment options include:
- Radiation therapy
- Pemetrexed-based chemotherapy (a type of chemotherapy that works particularly well in ALK-positive lung cancers)
- Immunotherapy (the body’s immune system is triggered to fight against lung cancer)
- Targeted therapies