Overall US Cancer Mortality Rate Reaches 26-Year Decline, but Obesity-Related Cancer Deaths Rise

The overall cancer death rate declined by 29% from 1991 to 2017, with a 2.2% decline from 2016 to 2017 serving as the largest single-year drop in reported cancer mortality, according to research published today in CA: A Cancer Journal for Clinicians; however, obesity-related cancer deaths are rising and prostate cancer deaths remain stagnant.

Cancer remains the second leading cause of death in the United States, with researchers from the American Cancer Society predicting the disease will affect more than 1.7 million people and cause 600,000 deaths in the nation this year. Overall cancer mortality has seen an average drop of 1.5% per year in the last decade (2008-2017), with the steady decline from 1991 translating to approximately 2.9 million fewer cancer deaths.

The decline can be attributed to long-term drops in death rates for the 4 major cancers—lung, colorectal, breast, and prostate. Lung cancer mortality rates, which constitute a quarter of all cancer deaths, represent a chief influence on the historic decline in cancer mortality, as the pace of mortality reductions has doubled in recent years from 2% to 4%, with further significant declines made over the long term among the other 3 major cancers:

• The death rate for breast cancer dropped by 40% from 1989 to 2017.
• The death rate for prostate cancer dropped by 52% from 1993 to 2017.
• The death rate for colorectal cancer dropped by 53% from 1980 to 2017 among men and by 57% from 1969 to 2017 among women.

Progress in treatment for melanoma of the skin drove the most rapid death rate decline seen in the research, as the overall melanoma death rate dropped by 7% per year during 2013-2017 in people aged 20 to 64 years. Prior to the FDA approval of 2 melanoma treatments, ipilimumab and vemurafenib, these death rates decreased by 2% to 3% each year among people aged 20 to 49 years, with a minimal decline of 1% in those aged 50 to 64 years. Since 2010, the 1-year survival for patients diagnosed with metastatic disease rose from 42% (2008-2010) to 55% during 2013-2015.

While these long-term declines show promise, reductions in death rates slowed for female breast and colorectal cancers, and halted for prostate cancer, causing lead study author Rebecca Siegel, MPH, scientific director of Surveillance Research at the American Cancer Society, to describe the significance of the study findings as mixed.

Furthermore, cancers that exhibited increases in death rates, such as thyroid, pancreas, and uterus, were all linked to obesity, stressing the public health crisis caused by the obesity epidemic. As African American (46.8%) and Hispanic (47%) adults were shown to be disproportionately affected by obesity, these minority groups represent definite at-risk groups.

“It’s a reminder that increasing our investment in the equitable application of existing cancer control interventions, as well as basic and clinical research to further advance treatment, would undoubtedly accelerate progress against cancer,” said Siegel.

Reference

Siegel RL, Miller KD, Jemal A. Cancer statistics, 2020 [published online January 8, 2019]. CA Cancer J Clin. doi: 10.3322/caac.21590.