Progress On Lung Cancer Drives Historic Drop In U.S. Cancer Death Rate

Special from NPR

Cancer death rates in the United States took their sharpest drop on record between 2016 and 2017, according to an analysis by the American Cancer Society.

Cancer death rates in the U.S. have been falling gradually for about three decades, typically about 1.5% a year. But during the latest study period, the cancer mortality rate dropped 2.2%, "the biggest single-year drop ever," says Rebecca Siegel, scientific director for surveillance research at the cancer society.

"It seems to be driven by accelerating declines in lung cancer mortality," Siegel says. That's "very encouraging, because lung cancer is the leading cause of cancer death in the U.S., causing more deaths than breast, colorectal and prostate cancers combined."

"This is unambiguously good news," says Dr. H. Gilbert Welch, senior investigator with the Center for Surgery and Public Health, at Brigham and Women's Hospital in Boston. He was not involved in the analysis.

What's behind the decline? In part, smoking rates have fallen steadily, which means the biggest risk factor for lung cancer has fallen appreciably. New cancer treatments are also playing a role, Siegel says.

Advanced lung cancer, however, remains deadly. People diagnosed with lung cancer that has spread elsewhere in the body have only a 5% chance of surviving for five years. And many smokers and former smokers are not following the advice to get screened with a low-dose CT scan to catch cancer early.

In fact, a recent study found that only 4.4% of people eligible for this screening test (which under the Affordable Care Act is available at no cost) actually got screened in 2015. Nearly twice as many people instead got a test that has been found to be unsuited as a screen for lung cancer: a chest X-ray.

And others who didn't fit the U.S. Preventive Services Task Force recommendations took the CT screening test anyway. "The number of adults inappropriately screened for lung cancer greatly exceeds the number screened according to the USPSTF recommendations," the study notes.

Screening for cancer has played a controversial role in cancer trends. Mammography and the PSA blood test for prostate cancer do identify some cancers early, when treatment is usually more effective. But the tests also identify many growths that would never turn deadly — a phenomenon called "overdiagnosis."

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