Many advances are being made in the treatment of lung cancers. Tumors in the lung may be treated with surgery, radiation, chemotherapy, targeted therapy, or combinations of these approaches. To recommend the best treatment for your cancer, your doctor needs to get as much information as possible about your tumor. Most of this information comes from tests performed on tumor samples obtained when you have a biopsy.
Understanding Your Tumor Type
Types of lung cancer: There are two basic types of lung cancers: small cell and non-small cell. Over 85 percent of all lung cancers are non-small cell lung cancers, while about 13 percent are small cell lung cancers.
Within the non-small cell lung cancer group, subtypes include adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Adenocarcinomas represent three quarters of these cases. These distinctions are important since they will help your team determine which chemotherapy is more likely to be effective or safe. For example, studies show that the drug pemetrexed (Alimta) works well in patients with adenocarcinoma, whereas the drug gemcitabine (Gemzar) works better in persons with squamous cell carcinoma. The drug bevacizumab (Avastin), while helpful in individuals with adenocarcinomas, can cause severe side effects in patients with squamous cell lung cancers.
Cancer stage: The stage of the cancer describes a cancer’s size, exactly where the cancer is found, and whether it has spread at the time of diagnosis. In early-stage lung cancer, the tumor is contained inside the lung. In metastatic lung cancer, the tumor has spread outside the lung to other organs in the body, such as the liver, brain, and bones. Your treatment options will differ depending on your cancer’s stage.
Tumor features: Examining tumor samples under a microscope gives doctors important information. It can tell them the tumor type and propensity to spread. This information helps guide your doctor’s recommendations about how best to treat your cancer.
Doctors recommend different treatments for lung cancer based on the type of lung cancer.
Biomarkers and Personalized Medicine
In the past, patients with the same type and stage of lung cancer received the same treatment. Today, researchers know that no two persons are exactly the same; no patients’ tumors are exactly the same. In some cases, doctors can use information about your tumor to help them decide whether one treatment is more likely than another to work in your case. This new approach to cancer treatment, called personalized medicine, is made possible by the discovery of biomarkers. Biomarkers are molecular characteristics of a tumor that can, in some cases, be used to help make decisions about treatment. Biomarker tests available to lung cancer patients include:
EGFR mutation analysis EGFR stands for epidermal growth factor receptor. EGFRs are structures found on the surface of some cells that take in messages, encouraging those cells to grow and divide. A mutation in the EGFR gene causes these receptors to be “on” all the time, even when they should not be. This causes the tumor to grow and divide more. Some new cancer drugs, such as erlotinib (Tarceva), block these signals. These drugs, called EGFR inhibitors, may kill cancer cells and shrink the tumor or stop it from growing. A test called EGFR mutation analysis can be performed on a sample of your tumor to help your doctor decide whether your cancer is likely to respond to treatment with an EGFR inhibitor.
ALK testing ALK testing is similar to EGFR mutation analysis. People with a mutation in the ALK (anaplastic lymphoma kinase) gene may respond to ALK inhibitors, which block signals that tell the tumor to grow and divide.
Proteomic testing A new blood test called VeriStrat is available for advanced non-small cell lung cancer patients. The test looks at protein patterns in the blood and predicts how patients are likely to respond after receiving an EGFR inhibitor. This test is useful for patients who are EGFR wild-type, or for patients who are chemo-ineligible. Because it is a blood test, VeriStrat does not require a tissue biopsy and results can be returned within three days.
KRAS mutation analysis KRAS is another gene that may cause cancer when it is mutated, or changed. Many lung cancers carry this mutation. Research shows that EGFR inhibitors may be less effective in tumors that carry a KRAS mutation. A test known as KRAS mutation analysis can tell your doctor whether your tumor carries this mutation.
Talk with your doctor about whether or not you should be tested for biomarkers, and what the results would mean for your treatment. Typically, your doctor sends the required blood or tissue sample to the company that provides the test, and results are received within a few days or weeks, depending on the test. Biomarker tests may be covered by your insurance. Check with your provider to be sure.