A report from the American Cancer Society published Jan. 5 reports that cancer deaths in the United States have fallen by 25 percent since 1991.
Rebecca L. Siegel, lead author of the study, tells CNN that an increase in cancer detection and prevention methods has saved more than 2.1 million lives over the last 25 years.
"Since the peak in 1991, cancer death rates have been declining by about 1.5 percent per year, not only because of the reduction in smoking, but also because of improvements in the early detection of cancer (through both screening and increased awareness) and advances in treatment," she told CNN via email. "We anticipate that death rates will continue to decline."
Time reports that cancer is the second-biggest killer in the United States, trailing only heart disease. Although researchers expect cancer death rates to decline, Siegel notes that it's not a guarantee, especially since obesity, a risk factor for cancer, is on the rise. Currently, researchers don't know the full effects of obesity on cancer mortality rates, but over 20 percent of cancer diagnoses in the United States are due to excess body weight, an unhealthy diet or a lack of physical exercise.
"We don’t know when we’re going to see the effects of the tripling of the obesity rate in the past several decades," says Siegel, adding that while rates of obesity-linked colorectal cancer are showing an overall decrease, they are rising in people under the age of 50.
The other three most common forms of cancer -- lung, breast, and prostate -- are showing general declines as well.
The study is exciting news for cancer researchers, whose hard work over the years appears to be having tangible results.
"It’s pretty exciting for us that the cancer death rate continues to decline,” Siegel tells Time. "We’re making a lot of progress."