The rate of cancer deaths in the United States saw the sharpest decline on record from 2017 to 2018 as new treatments and technologies improved survival rates, according to an American Cancer Society (ACS) report published Tuesday in CA: A Cancer Journal for Clinicians.

Cancer death rate sees sharpest decline on record

For the report, the researchers analyzed cancer mortality data from the National Center for Health Statistics from 1930 to 2018—a period of time before America's coronavirus epidemic began.

Overall, the researchers found that the U.S. cancer death rate has decreased by 31% from its peak of 215.1 deaths per 100,000 people in 1991 to 149 deaths per 100,000 in 2018.

Further, the researchers found that from 2017 to 2018, the U.S. cancer death rate decreased by a record 2.4%—marking the second year in a row that the United States has seen a record drop in its cancer death rate.

The researchers attributed the overall decline in U.S. cancer death rates between 1991 and 2018 to reductions in smoking and improvements in early cancer detection and treatment, as well as long-term decreases in mortality rates for breast, colorectal, lung, and prostate cancer. The researchers did note that declines in the death rate for breast and colorectal cancers have slowed recently, while progress has stalled for prostate cancer.

Specifically, the researchers estimated that declines in lung cancer deaths account for about 50% of the overall decrease in the country's cancer death rates over the past five years, while drops in breast cancer and colorectal cancer account for the remaining half, the Wall Street Journal reports.

According to Rebecca Siegel, senior scientific director of surveillance research at ACS and lead author of the new report, advancements in lung cancer treatments in particular have accelerated the overall decline in the country's cancer death rate, such as therapies that target specific cancer cells. The report found that the two-year survival rate for lung cancer increased from 30% during 2009 to 2010 to 36% during 2016 to 2017 as a result of progress in treating patients with non-small-cell lung cancer, which is the most common type of lung cancer.

The researchers also found that the incidence of some cancers is rising. For example, the researchers found the incidence rates of kidney, pancreas, melanoma, and oral cavity and pharynx cancers are increasing for both men and women.

Leading causes of cancer-related death in 2021

However, despite those declines the researchers projected that in 2020, lung cancer will remain the leading cause of cancer-related deaths in the United States among men and women:

In addition, the researchers found disparities in cancer-related deaths among Black and white Americans. According to the report, Black Americans are 13% more likely to die from cancer than white Americans. The researchers said many factors have led to the disparity.

"It honestly boils down to decades and decades of systemic racism," said Siegel. "People who are African American are not only diagnosed at a later stage for almost every cancer type, but even within each stage of diagnosis their survival is lower. This is not something related to biology for the most part ... this is largely because of reduced access to care."

Cancer remains second-leading cause of death

Despite the decline in the overall cancer deaths, the report found that cancer remains the second-leading cause of death in the United States after heart disease. According to the report, approximately 1.9 million cancer cases will be diagnosed in 2021.

The report also projected that 608,570 Americans will die from cancer this year, with the total number of deaths varying by state.

Covid-19's impact on cancer diagnoses and deaths

Although the report did not take into account the coronavirus epidemic, the researchers said they anticipate the epidemic will lead to more late-stage diagnoses and cancer deaths.

"It is strongly expected that disruptions of care in 2020 that continue into this year will increase diagnosis of advanced stage disease and cancer mortality. But that will play out over many years," said Siegel. "This will make prediction of cancer trends over the next few years difficult" (Abbott, Wall Street Journal, 1/12; Leslie, ABC News, 1/12; Sullivan, The Hill, 1/12; Siegel et al., CA: A Cancer Journal for Clinicians, 1/12).