For patients with metastatic lung cancer, immunotherapy is an exciting and significant treatment option, says Dr. Jennifer Garst, a medical oncologist at Duke Cancer Center. “It seems to work, to some extent, in the vast majority of patients [who receive the drugs],” she says. As with any drug, however, there are risks and potential side effects that patients should be aware of.
Tumors put the brakes on the immune system, which keeps it from killing cancer cells, Garst says. Immunotherapy drugs for lung cancer, called checkpoint inhibitors, include medications such as nivolumab (Opdivo) and pembrolizumab (Keytruda). These drugs take the brakes off so the immune system can do its job.
[See: 7 Things You Didn’t Know About Lung Cancer.]
Potential Side Effects from Immunotherapy
Adverse events from immunotherapy are usually a consequence of stimulating the immune system too much, so it attacks normal tissue, says Dr. David Carbone, a 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. However, on average, he says, immunotherapy has fewer — and different kinds of — side effects than chemotherapy.
Garst says immunotherapy is not like chemotherapy, which kills cancer cells and is then excreted from the body within 72 hours. “With immunotherapy, it actually switches the immune system to the ‘on’ position. Sometimes it’s hard to turn the immune system back down,” she says.
One of the most common side effects of immunotherapy is thyroid dysfunction, Carbone says. “Sometimes [thyroid effects] are not obvious clinically, so we check them routinely in patients on immunotherapy.” Most commonly, patients have low thyroid function and need thyroid supplementation. “That’s a very easy side effect to control and not really a problem,” Carbone says. However, once the thyroid is damaged, it does not recover, Garst adds.
The most common serious side effects of immunotherapy are colitis and pneumonitis, inflammation of the colon and lungs, respectively, Carbone says. Both occur in only about 1 percent of patients. “Colitis presents with abdominal pain and diarrhea. It can actually be fatal,” he says. Pneumonitis, which can also be fatal, shows up in early stages as changes on a CT scan or serious shortness of breath. As long as it’s diagnosed early and treated appropriately, Carbone says, pneumonitis rarely causes long-term problems.
[See: 7 Innovations in Cancer Therapy.]
In very rare cases, some combinations of immunotherapy drugs can cause the immune system to attack the brain, causing devastating neurologic complications, such as coma or paralysis. These effects are often not reversible, Carbone says.
Oncologists are trying to identify which patients are at high risk for developing serious side effects from immunotherapy, Garst says. While it’s still unknown, patients whose immune systems are very responsive to the drugs also appear to be most likely to experience side effects.
“With any therapy we give patients, we go over the risk/benefit analysis,” Garst says. “In general, the side effects of immunotherapy are more tolerable. There’s no hair loss, no nausea, no blood counts getting low.” Patients do report fatigue, however: “It’s a very common complaint with immunotherapy.”
As the immune system attacks cancer with the help of immunotherapy, the tumor may actually swell or increase in size before shrinking later, a phenomenon called pseudo-progression. This is fairly rare, Garst says. “It’s difficult to distinguish pseudo disease from real cancer tumor growth.” However, she adds, if patients are experiencing pseudo-progression but feeling better than they did before starting immunotherapy, oncologists will typically continue with the treatment and follow up with scans to monitor the tumor. If a patient is declining — feeling worse and having more pain plus less energy — it’s more likely to be real disease progression, Garst says. “It may be time to stop and change to a different therapy.”
Garst says about 10 to 15 percent of patients will experience some toxicity from immunotherapy. On the other hand, she says, about 5 to 10 percent of patients have a dramatic response (remission). “I suspect immunotherapy will change the course of survival for many people with stage 4 disease,” she says.
[See: What Not to Say to Someone With Lung Cancer.]
“Patients have to realize that these are not miracle cures,” Carbone says. “They do have side effects patients should be aware of, especially colitis and pneumonitis.” However, he says, patients with serious side effects are not common and, on balance, the effectiveness versus toxicity of immunotherapy agents is very good, especially since these patients are dealing with stage 4 lung cancer.
For now, immunotherapy is only approved for use in patients with metastatic lung cancer. Clinical trials are underway for patients with earlier stage cancer, Carbone says.
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Understanding the Side Effects from Immunotherapy for Lung Cancer originally appeared on usnews.com
