Causes of Lung Cancer
Epidemiology is the study and analysis of the patterns, causes, and effects of health and disease conditions in defined populations, including lung cancer. Much of the current research around lung cancer centers on epidemiologists researching the causes of lung cancer, which are still somewhat of a mystery.
Researchers at the Mayo Clinic are studying whether some inherited factors can influence the course of lung cancer, including response to treatment, disease progression, development of new cancer, survival and quality of life of the patients.
Still, more people die from lung cancer every year than from any other form of cancer. Knowing your risks and doing all that you can to lessen them is extremely important.
Early Detection of Lung Cancer
The good and bad news of lung cancer is that it is asymptomatic, meaning by the time symptoms appear it is usually at the late stage of the disease. The good news is that people can have a great quality of life without ever knowing they have lung cancer. The bad news is that any cancer is much harder to treat at an advanced stage. Over 80% of lung cancer patients are diagnosed when the cancer is already at an advanced stage.
Because so many lung cancers are diagnosed at a late stage, the overall survival rate for someone living 5 years after being diagnosed with lung cancer is 17%. That means that for every 100 people diagnosed with lung cancer, only 17 will still be living 5 years later.
For lung cancer patients who have been diagnosed while their disease is still in the earliest stages, that figure grows significantly. For every 100 people diagnosed with lung cancer caught at an early stage, 56 will still be living 5 years later.
In 2013, the National Lung Screening Trial (NLST) compared low dose CT scans (LDCT) and chest x-rays. Lung cancer researchers discovered that LDCTs of the chest provided more detailed pictures than chest x-rays and were better at finding abnormal areas in the lungs. This early detection trial resulted in recommending that those who exhibit risk factors for lung cancer receive an annual LDCT.
But what if you don’t exhibit risk factors? Researchers are actively trying to discover new ways to detect lung cancer earlier. Blood tests, nasal swabs, and sputum samples are all current areas of research for the early detection of lung cancer.
At the turn of the 21st century, the only major choice of treatments for lung cancer was surgery if your cancer was diagnosed early, or chemotherapy if it was diagnosed at a late stage. If you had surgery, your cancer may or may not reoccur. If you had chemotherapy, you might improve for a few months only to have your tumor start growing again.
The belief was that everyone’s lung cancer tumor was basically the same. Around 2007,The Cancer Genome Atlas (TCGA) discovered that, in fact, no two tumors are alike.
This discovery led to a radically different understanding of cancer and its potential treatments. Once a tumor’s unique mutations or biomarkers are identified, then treatments can be customized for those specific biomarkers. This has given rise to a whole new field of lung cancer research called biomarker testing. Examples are Next Generation Sequencing (NGS) and blood biopsies. Researchers are constantly trying to discover new and inexpensive ways to identify a tumor’s biomarkers.
Read more on how to get biomarker testing on your tumor if you have been diagnosed with lung cancer.
While on the topic of biomarkers, targeted therapies are cancer treatments that specifically target certain known mutational changes in cancer cells. Once the tumor’s unique biomarkers are identified, targeted therapies work to shut down or inhibit mutations that would otherwise make the cancer cells grow and divide.
Over 200 biomarkers have been identified in lung cancer, and researchers are currently focusing on those that occur most frequently. The FDA has approved targeted therapies for the following lung cancer biomarkers:
- EGFR (Epidermal Growth Factor Receptor)
- ALK (Anaplastic Lymphoma Kinase)
- ROS-1 (closely related to ALK)
- BRAF (the name of both a gene and a protein)
A tumor treated with a targeted therapy can develop resistance to that drug after a period of time. Sometimes the drug stops working because the tumor cells develop new mutations that effectively “outsmart” the drug, allowing the cancer to grow. New treatments are being discovered as a result of this exciting area of research.
Immunotherapy is the latest breakthrough in lung cancer research. It is understood that we all develop cancerous cells throughout our lives but that some immune systems are able to recognize the cancer cells as “bad” and attack them, while other immune systems do not. This discrepancy has led to a field of treatments known as immunotherapies, which teach a person’s own immune system to attack cancer cells. The FDA has approved some immunotherapies for lung cancer treatments that, for some patients, can be used as the first line of therapy, even before chemotherapy.
For some patients, once their own immune system learns to attack the cancer cells, it keeps attacking the cancer cells long after the immunotherapy is stopped. Researchers are still trying to understand why some why some patients’ cancers respond to immunotherapy, as well as why other patients’ cancers do not. Promising research is also being done on combining immunotherapy with chemotherapy and/or other targeted therapies for even greater results.