Over the past decade, lung cancer treatment has changed dramatically, especially for patients who have advanced stage disease. Many patients now benefit from a better understanding of what drives tumors to develop and grow and how they interact with our immune system and the surrounding environment. This has led to advances in areas of immunotherapy and targeted therapies.
[See: What Not to Say to Someone With Lung Cancer.]
Immunotherapy
Our body’s immune system recognizes things that may be dangerous — such as certain bacteria, viruses and cancer cells — and works hard behind the scenes to keep them from causing us harm.
Cancer is good at tricking the immune system, however. It can make it difficult for the immune system to recognize cancer as harmful, so it doesn’t attack and destroy the cancer cells. Immunotherapy treatments help the immune system do its job, either by marking cancer cells so the immune system can find them or by boosting its ability to fight the cancer.
When it works, it works well. “Immunotherapy has changed the standard of care for treatment of lung cancer and has already made a significant impact on survival for many patients,” says Dr. Leena Gandhi, director of thoracic medical oncology at the Perlmutter Cancer Center at NYU Langone Medical Center.
One immunotherapy breakthrough is helping some lung cancer patients whose tumors over-express (or make too many copies of) a protein called PD-L1. Immunotherapy treatments called checkpoint inhibitors block receptors on immune cells that signal the cell to turn off the immune response. One of these receptors is called PD-1, which is bound by a molecule called PD-L1 made by nearby immune cells or tumor cells. PD-1 serves as a signal to turn off the immune response in the immediate vicinity. In other words, by not allowing the interaction of PD-L1 and PD-1 to “check” the growth and proliferation of killer immune cells, these cells are released to grow, multiply and attack the cancer cells.
“About 25 to 30 percent of patients with non-small cell lung cancer [which accounts for about 85 percent of lung cancer cases] have high levels of PD-L1 on their tumor cells,” says Gandhi. “We test for PD-L1 in every patient now at diagnosis.”
The U.S. Food and Drug Administration has approved several immunotherapy drugs for lung cancers that over-express PD-L1. Most recently, it approved pembrolizumab for the first-line treatment of patients with metastatic (disease that has spread) non-small cell lung cancer whose tumors express PD-L1. “In clinical trials, treatment with pembrolizumab resulted in a 50 percent decreased chance of further cancer growth and a 40 percent reduction in the risk of death as compared with chemotherapy,” Gandhi says. The FDA had already approved pembrolizumab for lung cancer patients who did not initially respond to chemotherapy.
These drugs are not effective for all lung cancer patients, but they do seem to provide an overall survival benefit to a small subset of patients. “We don’t know yet for how long, but some patients have years of sustained remission,” Gandhi says. “We may be able to extend the benefit to larger groups of patients by combining PD-1 inhibitors with other drugs.”
Immunotherapy treatments have side effects ranging from mild or unpleasant — such as rashes and fatigue — to more serious or life threatening, such as potentially fatal inflammation of the intestines or lungs. Fortunately, life-threatening side effects are rare. Doctors can manage these side effects by stopping the medications, or giving other medications to blunt the treatment symptoms.
[See: 7 Things You Didn’t Know About Lung Cancer.]
Targeted therapy
Targeted therapies limit or prevent changes in cancer cells that help them grow.
“Every cancer is different,” says Dr. David Carbone, medical oncologist and director of the Thoracic Oncology Center at The Ohio State University Comprehensive Cancer Center — Arthur G. James Cancer Hospital and Richard J. Solove Research Institute. “We are learning how to analyze the genetic makeup of cancers. There are many genes that are abnormal in tumors, but not in the patients. Certain subsets of genes are very strong drivers of cancers.”
As oncologists uncover more and more of these mutations that drive cancer, they will continue to develop drug therapies that are effective and have less toxicity, Carbone says. “This is transforming lung cancer. Patients need to have a battery of molecular tests at the time of diagnosis to match the treatment to the patient.”
Many advanced-staged lung cancer patients don’t have any of the markers scientists have identified so far. Hopefully, this will change. “The research really matters,” Carbone says. “It improves therapies.”
[See: 7 Innovations in Cancer Therapy.]
Oncologists who treat lung cancer patients are optimistic. “We have really dramatic changes in treating lung cancer,” Gandhi says. “It’s no longer the same death sentence it was. Treatment is going to continue to change going forward.”
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New Treatments for Lung Cancer originally appeared on usnews.com
