The mortality-to-incidence ratio (MIR) is generally used as a high-level comparative indicator of inequities in cancer outcomes. MIR is a cruder indicator than relative survival (see NCCI measures 5-year relative survival, 10-year relative survival). However due to its simplicity (it is calculated by dividing the mortality count by the incidence count in a given year), it allows a prompt international comparison of survival across countries due to the ready availability of incidence and mortality data for most countries.1
Charts
About this measure
The MIR is a crude indicator of case fatality of a selected cancer. It can be used to compare different cancers (higher MIR values generally indicating poorer survival).1,2 The MIR can help to identify population groups with poorer survival outcomes which may warrant further investigation.3,4 The MIR can also be used for international benchmarking because incidence and mortality data of adequate quality are generally available from most countries, and the MIR is straightforward to calculate.1
The mortality-to-incidence ratio (MIR) is calculated by dividing the number of deaths for a selected cancer type in a given year by the number of newly diagnosed cases for that cancer in the same year. Generally, the MIR is used as a crude measure of the fatality of a particular cancer and can be interpreted as follows:
MIR less than 1 would indicate that fewer people died from a particular cancer than were diagnosed with that cancer in a given year.
MIR of 1 would indicate that the same number of people died from a particular cancer as were newly diagnosed with that cancer in a given year.
MIR of greater than 1 would indicate that more people died from a particular cancer than were diagnosed with that cancer in a given year.
As MIR is a ratio of two measures which may be changing over time, for various reasons, the MIR should be interpreted with caution, particularly when examining MIR trends. For instance, decreasing MIR over time could reflect improvements in survival (decreasing mortality) or increased diagnosis (increasing recorded incidence), or a combination of both. Additional contextual information is required to interpret differences in MIR by cancer type and how these may be changing over time.1
Current status
In 2019, the MIR for all cancers combined in Australia was 0.34. Of the selected cancer types analysed, those for which MIRs were markedly higher (indicating shorter survival) than for all cancers combined included oesophageal cancer (0.87), liver cancer (0.85), pancreatic cancer (0.80), brain cancer (0.79), lung cancer (0.66) and ovarian cancer (0.64). Selected cancer types with markedly lower MIRs (indicating longer survival) than for all cancers combined in 2019 included melanoma (0.09), breast cancer (females only) (0.17), colon cancer (0.14), prostate cancer (0.19), uterine cancer (0.21), head and neck cancers, including lip (0.25), Non-Hodgkin Lymphoma (0.27), and cervical cancer (0.26).
By sex
In 2019, the MIR for all cancers combined was similar for males (0.36) and females (0.32). Cancer types where there were notable differences in the MIR between males and females included bladder cancer (0.33 for males, 0.43 for females), liver cancer (0.77 for males, 1.04 for females), and rectal cancer (0.53 for males, 0.60 for females).
International comparisons
The MIRs for Australians are among the lowest for all cancers combined, and for 7 of 14 cancer types examined. MIRs were ranked second or third lowest when compared with selected developed countries. Australia’s relatively low MIRs suggest that cancer survival in Australia is high compared with similarly developed countries.
In 2019, among selected developed countries, Australia had the lowest MIR for all cancers combined (0.34) and for pancreas (0.80), as well as equal-second lowest for colorectal (0.34), liver (0.85), melanoma (0.09), breast (females only) (0.17), uterine (0.21) and Non-Hodgkin lymphoma (0.27).
Trends
From 1982 to 2019, the MIR for all cancers combined in Australia decreased from 0.52 to 0.34 (indicating increasing survival). Similar trends were observed for both males (from 0.56 to 0.36) and females (from 0.49 to 0.32) over this period. MIRs also decreased from 1982 to 2019 for most cancer types analysed; notable decreases were observed for breast cancer in females (0.37 to 0.17), colon cancer (0.59 to 0.14), liver cancer (1.24 to 0.85), lung cancer (0.89 to 0.66), non-Hodgkin lymphoma (0.50 to 0.27), and prostate cancer (0.38 to 0.19). These changes are consistent with the improved 5-year relative survival for these cancers observed over a similar period (see 5-year relative survival).
In 2019, MIRs for brain cancer increased slightly from 1982 (0.78 to 0.79), the overall trend for brain cancer remains relatively stable (peaking in 1990 at 0.89 and dropping to 0.72 in 2005).The MIR for bladder cancer increased from 0.28 to 0.35, this is likely due to changes in coding practice and age at diagnosis over time.1 The MIR for rectal cancer decreased from 0.37 in 1982 to 0.27 in 1996, and has since increased to 0.56 in 2019. This pattern mirrors that of the age-standardised mortality rate for rectal cancer (see Cancer Mortality), and may be due in part to changes in the way deaths attributed to bowel cancer are coded to specific sites of the digestive organs.6
About the data
Data sources for this measure are:
- Australian Institute of Health and Welfare (AIHW) 2022. Cancer data in Australia 2021. Canberra: AIHW, sourced from the AIHW Australian Cancer Database and the AIHW National Mortality Database
- International Agency for Research on Cancer (IARC) Global Cancer Observatory database for international data, which contains cancer incidence and mortality data from cancer registries around the world.
For national data, Cancer data in Australia (2020) contains incidence data from 1982 to 2017, with projections to 2021 and mortality data from 1968 to 2019, with projections to 2021. Further details on the methodology and relevant caveats are available at Cancer data in Australia.1
MIRs for 2018 and 2019 use actual mortality data and incidence projections.
The following cancer types have been included in the analyses of national data:
|
Cancer type and ICD-10 codes – ACIM Books |
|
|
All cancers combined (C00–C97,D45, D46, D47.1, D47.3–D47.5) (Mortality data includes C97) |
Lung (C33–C34) |
|
Bladder (C67) |
Melanoma of the skin (C43) |
|
Brain (C71) |
Non-Hodgkin Lymphoma (C82–C86) |
|
Breast (C50) |
Oesophagus (C15) |
|
Cervix (C53) |
Ovary (C56) (incidence data includes C57 and C58 wit histologies 8441, 8460, 8461) |
|
Colon (C18) |
Pancreas (C25) |
|
Colorectal (C18-C20) (mortality data includes C26) |
Prostate (C61) |
|
Head and neck incl. lip (C00–C14, C30–C32) |
Rectum (C19-C20) |
|
Liver (C22) |
Uterus (C54-C55) |
Unknown primary site (C80) has not been included in the analysis due to confounding impact of changes to ICD-10 code attribution for this cancer type.
The international data contains cancer incidence and mortality from cancer registries around the world. Various methodologies are applied to the Global Cancer Observatory (GCO) data differing by country and data availability. Data for Australia (in relation to international data), Canada, Germany, Ireland, Korea, New Zealand, Singapore, Sweden, the Netherlands, United Kingdom and the United States of America were observed and projected to 2020. Incidence rates for Chile, France and Japan were estimated from national mortality data by modelling, using mortality-to-incidence ratios derived from cancer registries in that country.5 Additional details on methodology and data availability can be found: https://gco.iarc.fr/today/data-sources-methods
Data presented for Korea is inclusive of the Republic of Korea only.
The following cancer types have been included in the analyses of international data:
|
Cancer type and ICD codes – GLOBOCAN 2018 |
|
|
All cancers combined excluding non-melanoma skin cancer (C00-97, excluding C44) |
|
|
Bladder (C67) |
Melanoma of skin (C43) |
|
Brain, nervous system (C70-72) |
Non-Hodgkin lymphoma (C82-86,C96) |
|
Breast (C50) |
Oesophagus (C15) |
|
Cervix (C53) |
Ovary (C56) |
|
Colorectal (C18-21) |
Pancreas (C25) |
|
Liver (C22) |
Prostate (C61) |
|
Lung (C33-34) |
Uterus (C54) |
References
References
- Australian Institute of Health and Welfare 2022. Cancer data in Australia. Canberra: AIHW.
- Sunkara V and Hebert JR 2015. The colorectal cancer mortality-to-incidence ratio as an indicator of global cancer screening and care. Cancer 121:1563–1569.
- Hebert JR, Daguise VG, Hurley DM et al. 2009. Mapping cancer mortality-to-incidence ratios to illustrate racial and sex disparities in a high-risk population. Cancer 115(11):2539–2552.
- Feletto E and Sitas F 2015. Quantifying disparities in cancer incidence and mortality of Australian residents of New South Wales (NSW) by place of birth: an ecological study. BMC Public Health 15:823.
- Ferlay J, Ervik M, Lam F, Colombet M, Mery L, Piñeros M, Znaor A, Soerjomataram I, Bray F (2018). Global Cancer Observatory: Cancer Today. Lyon, France: International Agency for Research on Cancer. Available from: https://gco.iarc.fr/today, accessed May 2022.
- Australian Bureau of Statistics (ABS) 2016. Causes of death, Australia, 2015: complexities in the measurement of bowel cancer in Australia. ABS cat no. 3303.0. Canberra: ABS.