February 15, 2019 by John Fernandez and Tanya Racoobian
Lung Cancer is Pervasive, But There’s Progress in Fighting Deadliest Tumors
Even as the overall smoking rate is projected to continue declining in the U.S., 4.4 million Americans could die from lung cancer during the next five decades, says a newly published study.
For now, lung cancer is the second most common cancer diagnosed in the U.S. for both men and women, and it remains the No. 1 cause of cancer death. Each year, more people die of lung cancer than of colon, breast, and prostate cancers combined. And nearly half of lung cancer diagnoses are late-stage or advanced forms of the disease.
Smoking significantly raises the risk for many cancers and it is, by far, the leading cause of lung cancer. Nonetheless, as many as 20 percent of the people who die from lung cancer have never smoked or never used other forms of tobacco. The rate of lung cancer deaths among “never smokers” is projected to rise over the next 50 years.
November is Lung Cancer Awareness Month, and the American Cancer Society is highlighting its campaign by helping fund research to help prevent, screen for, diagnose, and treat lung cancer.
No. 1 Cancer Killer
“Lung cancer is pervasive,” says Miguel Villalona-Calero, M.D., deputy director and chief scientific officer at Miami Cancer Institute. “It is the No. 1 cancer killer of men and women. It kills more women than breast cancer. It kills more men than prostate cancer, even though both breast cancer and prostate cancer are more common.”
Dr. Villalona emphasizes that the only recommended screening test for lung cancer is low-dose computer tomography (also called a low-dose CT scan, or LDCT). Such a test involves an X-ray machine that scans the body and uses low doses of radiation to make detailed pictures of the lungs.
But these screenings are recommended only for certain adults at a high risk for lung cancer, including former smokers. Individuals eligible for screening represent fewer than 50 percent of newly diagnosed lung cancer cases. Moreover, because symptoms can be non-existent, mild or not considered serious enough in the early development of lung cancer tumors, many patients are diagnosed with the disease in late stage, and that creates a bigger challenge in keeping the cancer from spreading or intensifying, he says.
Despite the screening challenges, new treatments that use advances in medicine, technology and the patient’s own immune system to fight lung cancer are fueling optimism after decades of survival rates not increasing much for late-stage cancer diagnoses.
“Studies that have looked at the survival at 5 years for patients afflicted by lung cancer over the last few decades have changed only 1 or 2 percent — still a very low rate of survival,” says Dr. Villalona. “But I’m a bit more optimistic when it comes to lung cancer treatment than I’ve been in the past because we have more tools than we’ve ever had.”
But two different approaches to fighting lung cancer, particularly in its advanced forms, have pushed survival rates upward and improved the quality of lives of late-stage cancer patients. These two approaches are molecularly targeted therapy and immunotherapy.
Molecularly Targeted Therapy
One type of evolving treatment uses drugs or other substances to target specific molecules involved in the growth and spread of cancer cells. Blocking these molecules may kill cancer cells or may keep them from growing or spreading. Molecularly targeted therapy may cause less harm to normal cells and may have fewer side effects than other types of cancer treatment, including radiation and chemotherapy.
“Lung cancers are not all the same,” explains Dr. Villalona. “They are made in different ways and you have to understand that to improve treatment.”
There is a group of cancers in which there a gene mutation in the human body that drives the tumor. About one-third to 40 percent of lung cancers have these mutations, he says.
“The cancer obeys the signals of the mutations and follows them,” he says. “And the ability to identify those mutations has led us to molecularly targeted therapies that are different than chemotherapies. And these new therapies are able to stop the cancer from growing and in many cases they are able to produce tremendous shrinkage. It can really prolong your life significantly in cancers that are found in advanced stages.”
In some patients, molecularly targeted therapy involves taking pills over a couple of years, he says. In some patients, the medication can be prescribed for many years. “What we try to do is a game of catch-up,” explains Dr. Villalona. “If resistance occurs (to the currently prescribed pills), we look for other medications that can target that resistance. Now we have several medications that target that resistance when it appears.”
Immunotherapy: Patient’s Immune System Fights Cancer
Immunotherapy is a treatment that helps cancer patients use their own immune system to fight the cancer, or keep it from spreading. Normally, the immune system helps the body fight infections and other diseases. It is made up of white blood cells and organs and tissues of the lymph system.
The field of immunotherapy to fight cancer is evolving quickly and holding much promise in fighting lung cancer and other cancers. Immunotherapies either stimulate the activities of specific components of the immune system, or counteract signals produced by cancer cells that suppress immune responses, according to the U.S. National Cancer Institute.
“What we call the body’s immune checkpoints allows the cancer to have its way,” says Dr. Villalona. “And your body’s T-cells don’t battle the cancer like they are supposed to. With immunotherapy, we are able to turn off those checkpoints, or switches, and your immune system then starts acting against the cancer.”
The U.S. Food and Drug Administration has said it is committed to expediting the approval of immunotherapy drugs to fight different types of cancer.
“Those medications are becoming more common and they can help up to 60 percent of lung cancer patients,” says Dr. Villalona. “For these patients, there is a role for immunotherapy, either in combination with chemotherapy or by itself.”