Breakthrough treatments for lung cancer and melanoma have driven down cancer deaths, seeing the largest ever decline from 2016 to 2017.
The cancer death rate in the United States fell 2.2% from 2016 to 2017-the largest single-year decline in cancer mortality ever reported, according to a recent report by the American Cancer Society.
In almost two decades, the rate has dropped 29%. This translates to approximately 2.9 million fewer cancer deaths than would have occurred if the mortality rate had remained constant.
Experts attributed the decline to the reduced smoking rates and to advances in lung cancer treatment. New therapies for melanoma of the skin have also helped extend life for many people with metastatic disease, or cancer that has spread to other parts of the body, the report says.
However, progress has slowed for colorectal, breast and prostate cancers.
The increasing rate of obesity among Americans and significant racial and geographic groups explains why the decline in breast and colorectal cancer death rates has begun to taper off, and why the decrease in rates of prostate cancer has stopped entirely.
Cancer remains the second leading cause of death after heart disease in both men and women nationally.
The American Cancer Society predicts that this year there will be about 1.8 million new cancer cases and over 600,000 cancer deaths. Lung cancer kills more people than breast, prostate, colorectal, and brain cancers combined, the report says.
“We are still dealing with the effects of cigarette smoking from the 1960s and 70s in today’s population,” says Otis Brawley, an oncologist at Johns Hopkins University and former chief scientific officer at the American Cancer Society.
People who stopped smoking may develop lung cancer years later because there is a lag between exposure and cancer diagnosis. However, these rates should continue to go down, Brawley says.
In the last decade, several important advances in diagnosing and treating lung cancer have also helped avoid patient deaths. New imaging technologies have allowed doctors to accurately study the stage of the cancer and its prognosis. Less invasive surgical approaches have sped up recovery times, also.
In addition, immunotherapy has helped some patients by enlisting their T cells to kill their tumors.
Similar treatment breakthroughs have completely reversed trends in melanoma. In 2011, the FDA approved two new therapies, ipilimumab and vemurafenib, for metastatic melanoma. The melanoma mortality rate began declining by 7% per year among men and women 20 to 64 year, and by 5% to 6% per year in individuals 65 and older.
Rebecca Siegel, director of surveillance research at the American Cancer Society and lead author of the organization’s report, says what is so dramatic about the decline is that for people 65 and older, melanoma mortality rates were actually increasing in the 2000s.
However, as more Americans put on excess pounds, the rate of obesity-related cancers is increasing. These include liver, kidneys, pancreas, uterus, and breast cancers, as well as colon and rectal cancers in adults younger than 55.
Studies have found that obesity, unhealthy diets and a lack of physical activity are associated with metabolic and hormone abnormalities and with chronic inflammation, which may help explain the link to cancer, the report says.
Controlling these factors could help jump-start declines in cancer incidence and death rates, says Timothy Rebbeck, an epidemiologist at Harvard and the Dana-Farber Cancer Institute.
However, not all populations benefit from prevention and advances in cancer treatment. The American Cancer Society report found black men were still twice as likely to die of cancer as Asian/Pacific Islander men and 20% more likely to die than white men.
Men and women living in certain states are also more likely to develop and succumb to potentially preventable cancers, such as lung cancer, cervical cancer, and melanoma. This is due to smoking, obesity, other cancer risk factors and the ability to access and afford quality cancer care, Siegel says.
"Ensuring equal access to known cancer prevention and early detection methods would go far to accelerate the progress against overall cancer,” Siegel says.