Years of life lost as a measure of cancer burden on a national level

Abstract

Background: The severity of cancers is often measured in number of deaths. However, number of years of life lost (YLL) may be a more appropriate indicator of impact on society. Here we have calculated the YLL of adult cancers in Norway for the year 2012, as well as for the previous 15-year period.

Methods: Data on age composition, expected remaining years of life, total numbers of deaths and deaths due to cancer were retrieved from the National Census Agency Statistics Norway. YLL were calculated for both sexes aged 25-99 years based on each individual's age at death, and the expected remaining years of life at that age.

Results: Cancer deaths represented 25.8% of all adult deaths in 2012, with a lower fraction of females (28.7% in men and 23.1% in women), whereas cancer represented 35.2% of all YLL, with a higher fraction of females (32.8% in men and 37.8% in women). Females loose on average more life years to cancer than men (14.9 vs 12.7 years). Average YLL varied from 23.7 (cervical cancer) to 7.9 (prostate cancer). Lung cancer caused almost as many YLL alone (22.1% of cancer-caused YLL) as colon, prostate and breast cancer combined (23.1%). From 1997 to 2012, cancer-caused YLL as a fraction of all YLL increased from 32.5% to 35.2%, but with major differences among diagnoses.

Conclusions: Cancer is a major and increasing cause of premature deaths, and YLL may be a more accurate measure than number of deaths. Public health efforts and research funding should be explicitly directed at preventing premature deaths.

Figure 1

Total number of cancer-caused deaths in Norway in 2012 for both sexes per 5-year age group.

Figure 2

Percentage YLL of total cancer-caused YLL in Norway in 2012 for 18 most frequent cancer types. Percentage YLL of total cancer-caused YLL in Norway 2012 for 18 most frequent cancer types, both sexes combined (A). Average YLL of the 18 most frequent cancer types (B).

Figure 3

Number of deaths of individual cancer types in Norway in 2012 as a percentage of all cancer deaths (y axis) and total YLL of the same cancer type as a percentage of all cancer-related YLL (x axis). The ratio of YLL (%) to deaths (%) (A) and the ratios (log scale) of YLL (%)/mortality (%) are shown for the 18 most frequent cancers (B).

Figure 4

YLL caused by lung, colon and prostate cancer for men (A), and by lung, breast and colon cancer for women (B), shown for 5-year age groups from 25 to 99 years in Norway in 2012.

Figure 5

Cancer-caused deaths. Cancer-caused deaths as percentage of all deaths for each sex, and combined (dotted lines) and cancer-caused YLL as percentage of all YLL for each sex, and combined (solid lines) in Norway for the period 1997–2012 (A). Deaths and YLL caused by lung, colon or prostate cancer for men (left panel), and by lung, colon and breast cancer for women (right panel) as percentage of all cancer deaths and YLL per sex in Norway in the period 1997–2012 (B).

Figure 6

The relative increase or decrease in YLL from 1997 to 2012 for the individual diagnoses as well as cancer in total. The relative increase or decrease in YLL from 1997 to 2012 for the individual diagnoses as well as cancer in total for males (A) and females (B). The size of the balls reflects the magnitude of YLL in 2012 caused by the respective diagnoses.