A New Study Says U.S. Lung Cancer Rates Are Falling

Lung cancers are the most dangerous cancers in the United States, but according to recent data from the National Cancer Institute, there’s good news — rates of lung cancer in America are falling. That may be because of increased awareness of the dangers of smoking, and increase prevalence of smoke-free public spaces. While experts have already known that lung cancer rates in America have been dropping off, this latest study gives exact figures, and information about trends in the rates of various subtypes of lung cancer. The overall number of lung cancer cases declined by 12 percent between 1977 and 2010, researchers report.

Some Subtypes of Lung Cancer on the Decline

In this latest study, National Cancer Institute researcher Dr. Denise Lewis and her team analyzed data collected from over 450,000 people diagnosed with some type of lung cancer between 1977 and 2010. The data were collected as part of the Surveillance, Epidemiology, and End Results (SEER) Program.

The researchers wanted to learn more about the rates of specific lung cancer subtypes among various ethnicities and among men as compared to women. They looked at lung cancer rates among whites, blacks, non-white Hispanics, Asians and Pacific Islanders, and white Hispanics diagnosed between 1992 and 2010. Dr. Lewis and colleagues discovered that rates of small cell and squamous cell carcinomas have dropped off significantly since the 1990s. The researchers also discovered a decline in the overall number of non-specified lung-cancer cases.

Rates of these cancers among men have dropped off much more than they have among women. It’s believed that’s because men start smoking at a younger age than women, and so begin to develop lung cancer much sooner. With time, the researchers expect male and female lung cancer rates to approach one another.

While the rates of certain lung cancers are on the decline, there’s bad news, too. Rates of at least one lung cancer subtype are increasing.

Adenocarcinomas on the Rise

Rates of adenocarcinoma, a slow-growing subtype of lung cancer that appears in the outer layers of the lung tissue, are increasing. Dr. Normal Edelman of the American Lung Association believes that recent changes in the way people use cigarettes are to blame for increasing adenocarcinoma rates. In recent decades, low-nicotine, low-tar cigarettes have become more popular. People who smoke these cigarettes are more likely to smoke more and inhale the smoke more deeply, in an effort to get more nicotine out of them.

“The deeper you breathe in smoke, the more likely the cancer-causing tars are going to get into the outer area of the lungs, and that’s where adenocarcinoma starts,” Dr. Edelman told WebMD.

But since adenocarcinoma is a slower-growing form of lung cancer, it’s more likely than some subtypes to be diagnosed before it spreads outside the lungs. This means that lung cancer treatments for adenocarcinoma are more likely to be effective.

Cigarette smoking is still directly responsible for 90 to 95 percent of lung cancer cases diagnosed in the United States. It has even been called a contributing factor in cases where other carcinogens, like radon, were involved. As smoking becomes less and less common, researchers believe that lung cancer, too, will become rare.