Treatments for lung cancer have improved significantly over the last decade. During the last 10 years, newer medications have emerged that are helping people live longer and better quality lives. One of those discoveries was targeted therapies.
How Targeted Therapies Treat Lung Cancer
As researchers have learned more about the changes in cancer cells that help them grow, they have developed targeted therapies to target those changes specifically. “Targeted therapies are really going after the specific cause, the specific molecule that’s abnormal and producing the cancer,” says Jorge Gomez, MD, a lung oncologist at Mount Sinai Hospital.
Targeted therapies work differently from standard chemotherapy (chemo) drugs. Chemotherapies are designed to kill any rapidly dividing cell (which tend to be cancer cells), but because they don’t have a specific target so they kill healthy cells as well. “[Chemotherapy] is a toxic drug that kills any cell, including normal cells that are dividing rapidly,” says Dr. Gomez.
Because targeted therapies focus on killing cancer cells and spare the healthy cells, they tend to cause less side effects than chemo.
The only drawback to targeted therapies, however, is that they can’t help all lung cancer patients. “There is a group of patients, approximately 15 to 20 percent of patients with lung cancer, who have a special type of lung cancer that can be treated with targeted therapies,” says Dr. Gomez.
Who Target Therapies Can Help
“Targeted therapies are appropriate for patients who have those activating mutations or changes in the cancer cell that can respond to those targeted therapies,” says Dr. Gomez. “So patients who have the target.”
Patients with these mutations are usually never smokers, says Dr. Gomez. “Their lung cancers are generally thought not to be related to tobacco, so for that segment of the population, this treatment is significantly better than chemotherapy.”
These mutations might include blood vessel growths in the tumor, and cells with EGFR, ALK, BRAF, RET, or ROS1 gene changes. Generally, a sample of the patient’s tumor is analyzed in the lab to learn whether or not they have any of these abnormalities, a process called genomic testing. “Genomic testing has significantly changed how lung cancer is treated,” says Dr. Gomez.
The presence of these abnormalities then help the doctor narrow down the best treatment option for the patient. “We talk about all of the drugs that are available for each of those mutations,” says Dr. Gomez. “[We] always choose the best drug looking at efficacy and looking at safety or toxicity.”
How Doctors Know Targeted Therapy Is Working
Targeted therapies tend to work very quickly. “It’s not uncommon for us to see patients whose symptoms have disappeared within a week or two weeks of treatment,” says Dr. Gomez. “We often know whether drugs are working even before we do the first scans.”
Alongside learning that a patient is feeling significantly better, doctors may perform imaging tests to check on the status of the tumor. “CT scans, MRI, and PET scans can tell us whether the tumor is shrinking,” says Dr. Gomez.
If the doctors notice that the patient’s current drug isn’t performing in the same way, they have a backup plan. One of the most important changes in targeted therapy treatment is that there are now drugs designed to attack specific targets that may arise after the first treatment. “So when these drugs stop working, we now have other third generation drugs and we are developing subsequent generation drugs that may affect or even attack second resistance mutations,” says Dr. Gomez.
“In those patients who have activating mutations in the cancer cells where we can use targeted therapy, the outcome is significantly better,” says Dr. Gomez. “For that population of 15 to 20 percent of lung cancer patients, this has changed their life significantly.”