Cancer mortality rates are often used to calculate the burden of cancer in a society, but another measure -- potential years of life lost (PYLL) -- can also be useful because it can estimate the impact of cancer-related premature deaths that occur in younger individuals, according to a team led by Dr. Minkyo Song, PhD, a research fellow at the U.S. National Cancer Institute (Cancer Epidemiology, Biomarkers & Prevention, November 13, 2020).
To calculate potential years of life lost, Song et al examined U.S. national death certificate data and grouped it by 45 categories based on cancer type. They defined PYLL as the sum of total years of life lost before the age of 75. The most recent year of data acquisition was 2017.
Overall, the group found that 4.28 million potential years of life lost occurred due to cancer in 2107, compared to 4.26 million PYLL in 1990. The reason for the slight increase was the growth in the U.S. population, as cancer mortality has actually fallen over this time period from 215 deaths per 100,000 to 153 deaths per 100,000. Also in 2017, an average of 12 years of life before age 75 was lost per cancer death.
The group found that cancers that caused the largest number of deaths also caused the highest number of potential lives lost. But there were variances, particularly for cancers that typically occur at younger ages.
|Potential life years lost by cancer type in U.S.
||Total potential life years lost (PYLL)
||PYLL per death
|Lung and bronchus
|Colon and rectum
|Liver and intrahepatic bile duct
|Brain and other nervous system
Of the cancers that contributed to the most potential life years lost per death, testicular cancer was the highest, at 34 years lost per death, followed by cancer of the bone and joints at 26.4 years lost, and other endocrine cancers including thymus at 25.2.
While the number of lost years roughly tracked cancer incidence, one exception was prostate cancer, which causes about 5.1% of U.S. cancer deaths but only 2% of PYLL. The reason is that prostate cancer typically occurs later in life, Song et al noted.
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