The American Cancer Society reports that lung cancer is the second most common cancer in America today, constituting about 14 percent of all new cancer diagnoses. That means about 234,030 new cases of lung cancer are expected to be diagnosed in 2018, and about 154,050 people are expected to die of the disease this year, making it the leading cause of cancer death.
The problem with lung cancer is that it’s often diagnosed at a later stage when standard treatments such as surgery, chemotherapy and radiation aren’t as effective. But that reality may be changing as newer treatments — in particular a class of drug therapies called immunotherapies — are becoming more widely available to combat metastatic disease.
[See: What Not to Say to Someone With Lung Cancer.]
The ACS reports that immunotherapy medications “stimulate a person’s own immune system to recognize and destroy cancer cells more effectively.” They’re currently being used to treat some forms of non-small cell lung cancer, the most common type, accounting for 80 to 85 percent of all lung cancers. These immunotherapies, called immune checkpoint inhibitors, target molecules on immune cells that prevent the cells from attacking cancer cells. These drugs help immune cells “see” cancer cells as dangerous and attack them accordingly. For the past couple of years, these drugs have been helping to extend life for some lung cancer patients, but a new application of them in combination with chemotherapy may well be the next wave in treating advanced-stage lung cancer.
“When somebody is diagnosed with stage 4 lung cancer, the disease has traveled to other parts of the body and the usual approach is to use drug therapy,” says Dr. James Stevenson, an oncologist specializing in lung cancer at the Cleveland Clinic. A single type of chemo drug may be used, or doctors may opt to combine two or three different drugs, depending on the specifics of each case. “Traditionally, we’ve used combinations of chemotherapy drugs because we know these combination drugs, what we call platinum-based combinations, provide more benefit than if you used one drug by itself,” Stevenson says.
Benefit is typically measured by how long the drugs prolong survival, because stage 4 lung cancer “is incurable.” Doctors also measure benefit by whether the patient’s tumors shrink and whether their symptoms improve, “hopefully without too much in the way of side effects so the patient can have a longer life but also a better quality of life. That’s the goal that we look at when treating these patients,” Stevenson says. The overall life expectancy of a stage 4 lung cancer patient is typically measured in months, even with these combined chemotherapy drugs. But it appears that adding immunotherapy to chemotherapy could extend survival for some patients into many more months and sometimes even years.
Researchers still have many questions to answer with regard to how best to use these combination therapies and who the best candidate is for any new drug or therapeutic approach, says Dr. Laurie Carr, associate professor of oncology at National Jewish Health in Denver. “Whenever we have a new therapy in lung cancer, we have to ask ourselves, ‘Is it better to add it to something we’re already using or use it in sequence?'”
She says doctors also must consider whether the potential benefits of adding another drug are worth the risk of additional side effects. Taking three drugs at once “may work better than taking just two, but you’re taking on side effects from that entire combination, not to mention time in the infusion room and cost. So the other question we need to ask is, ‘Are there certain populations or individuals who would do better if we started by combining three drugs together?'”
[See: 7 Innovations in Cancer Therapy.]
Stevenson notes that immunotherapy drugs tend to be better tolerated than traditional chemotherapies. “We don’t typically see the familiar chemotherapy side effects such as hair loss, lowering of blood counts or nausea and vomiting.” However, some patients do experience severe side effects from immunotherapies. Because these drugs trigger the immune system, in some people it over-responds, leading to inflammation and symptoms such as rashes, fatigue and fever. “Generally, we’re able to take care of it with drugs like prednisone to help calm that down. It happens in a small percentage of patients, but … we have to keep an eye out for it,” Stevenson says.
The trend toward more personalized treatment across all cancer types fits in the discussion here as doctors consider treatment protocol for individual patients and whether it makes sense to combine therapies or use multiple drugs in succession as the cancer develops a resistance to each subsequent treatment. Carr says researchers are hunting for clues as to how a patient’s cancer will respond to individual or combination therapies. “Is there some marker on the tumor or something that will tell us, ‘With this one you should combine treatments. With this one you can do just as well with one drug and save the side effects.'”
Stevenson says a tumor marker called PD-L1 has helped add some detail to researchers’ understanding of whether a patient will respond to combination therapies. “It’s not a very precise marker or very predictive for all patients who might benefit,” but patients who have higher levels of that protein in the tumor appear to respond better to combination therapies. Another marker called tumor mutation burden, or TMB, may also be an indicator that certain patients will respond better than others, and researchers are continuing to investigate other means of matching the right treatment to the right patient as quickly as possible.
Once we have a better understanding of which patients are most likely to respond favorably to combination therapies, the hope is that patient life expectancies will improve dramatically for more people. Stevenson cautions that research is still in the early days and more study is needed, in part because patients who’ve been treated with these newer approaches are living longer and “we need longer follow up from the trials to really appreciate the magnitude of the results.” But so far, results are encouraging.
[See: 7 Things You Didn’t Know About Lung Cancer.]
Although Carr says these combination treatments aren’t currently thought of as a cure because “it can’t get rid of every cancer cell forever, adding immunotherapies in, whether on their own or combined with chemotherapy, has certainly shown an improvement in survival” timelines. Some of Carr’s patients have been on these combined therapies “for two years without having to change the protocol because it’s such a durable response. That’s extremely uncommon with chemotherapies,” she says, as cancer cells are adept at developing resistance to drug therapies over time. “Eventually, the cancer cells figure out how to get around the treatment. The cells become resistant to the treatment and they mutate or change their behavior to get around the drug. That’s true of the targeted therapies and the immunotherapies,” Carr says, but the hope is that someday we’ll be able to outsmart these mutations and stop cancer right from the beginning with a prescription tailored specifically to the individual case.
More from U.S. News
What Not to Say to Someone With Lung Cancer
7 Innovations in Cancer Therapy
7 Things You Didn’t Know About Lung Cancer
Are Combination Therapies the Next Wave for Treating Lung Cancer? originally appeared on usnews.com
