Cancer of unknown primary incidence statistics

Cases

New cases of cancer of unknown primary each year, 2017-2019 average, UK.

 

Proportion of all cases

Percentage cancer of unknown primary is of total cancer cases, 2017-2019, UK

 

Age

Peak rate of cancer of unknown primary cases, 2017-2019, UK

Trend over time

Change in cancer of unknown primary incidence rates since the early 1990s, UK

 

Cancer of unknown primary is the 15th most common cancer in the UK, accounting for 2% of all new cancer cases (2017-2019).[1-4]

In females in the UK, cancer of unknown primary is the 11th most common cancer (2% of all new female cancer cases). In males in the UK, it is the 15th most common cancer (2% of all new male cancer cases).

52% of cancer of unknown primary cases in the UK are in females, and 48% are in males.

Cancer of unknown primary incidence rates (European age-standardised (AS) rate Open a glossary item) for persons are significantly higher than the UK average in Scotland and Wales and significantly lower than the UK average in England and Northern Ireland.

For cancer of unknown primary, there are few established risk factors therefore differences between countries largely reflect differences in diagnosis and data recording.

Cancer of Unknown Primary (C77-C80), Average Number of New Cases Per Year, Crude and European Age-Standardised (AS) Incidence Rates per 100,000 Population, UK, 2017-2019

  England Scotland Wales Northern Ireland UK
Female Cases 3,421 424 270 96 4,212
Crude Rate 12.1 15.2 17.0 10.1 12.5
AS Rate 11.5 14.2 14.8 10.6 11.9
AS Rate - 95% LCL 11.3 13.4 13.8 9.4 11.7
AS Rate - 95% UCL 11.8 15.0 15.8 11.8 12.1
Male Cases 3,154 360 263 86 3,863
Crude Rate 11.4 13.6 17.0 9.3 11.8
AS Rate 13.5 15.8 18.1 12.4 13.9
AS Rate - 95% LCL 13.3 14.9 16.9 10.9 13.7
AS Rate - 95% UCL 13.8 16.7 19.4 13.9 14.2
Persons Cases 6,575 784 533 182 8,075
Crude Rate 11.7 14.4 17.0 9.7 12.2
AS Rate 12.4 14.9 16.2 11.4 12.8
AS Rate - 95% LCL 12.3 14.3 15.4 10.5 12.6
AS Rate - 95% UCL 12.6 15.5 17.0 12.4 13.0

95% LCL and 95% UCL are the 95% lower and upper confidence limits around the AS Rate Open a glossary item

References

  1. England data were provided by the National Cancer Registration and Analysis Service (NCRAS), part of the National Disease Registration Service (NDRS) in NHS England, on request through the Office for Data Release, January 2023. Similar data can be found here: https://www.cancerdata.nhs.uk/ 

  2.  Northern Ireland data were provided by the Northern Ireland Cancer Registry (NICR) on request, October 2021. Similar data can be found here:http://www.qub.ac.uk/research-centres/nicr/. 

  3. Welsh data were published by the Welsh Cancer Intelligence and Surveillance Unit (WCISU), Health Intelligence Division, Public Health Wales https://phw.nhs.wales/services-and-teams/welsh-cancer-intelligence-and-surveillance-unit-wcisu/cancer-reporting-tool-official-statistics/ June 2022. 

  4. Scotland data were provided by the Scottish Cancer Registry, Public Health Scotland (PHS) on request, May 2021. Similar data can be found here: https://publichealthscotland.scot/publications/show-all-releases?id=20468

About this data

Data is for UK, 2017-2019, ICD-10 C77-C80.

Last reviewed:

In the UK in 2017-2019, on average each year almost 6 in 10 new cases (58%) were in people aged 75 and over.[1-4].

Age-specific incidence rates rise steadily from around age 45-49 and more steeply from around age 70-74. The highest rates are in the 90+ age group for females and males.

Incidence rates are significantly lower for females than males in a number of (mainly older) age groups. The gap is widest at age 55 to 59, when the age-specific incidence rate is 1.3 times lower for females than males.

Cancer of Unknown Primary (C77-C80), Average Number of New Cases per Year and Age-Specific Incidence Rates per 100,000 Population, UK, 2017-2019

For cancer of unknown primary, like most cancer types, incidence increases with age. This largely reflects cell DNA damage accumulating over time. Damage can result from biological processes or from exposure to risk factors. A drop or plateau in incidence in the oldest age groups often indicates reduced diagnostic activity perhaps due to general ill health.

See also

Cancer of unknown primary mortality statistics by age

Cancer incidence statistics by age for all cancers

References

  1. England data were provided by the National Cancer Registration and Analysis Service (NCRAS), part of the National Disease Registration Service (NDRS) in NHS England, on request through the Office for Data Release, January 2023. Similar data can be found here: https://www.cancerdata.nhs.uk/ 

  2.  Northern Ireland data were provided by the Northern Ireland Cancer Registry (NICR) on request, October 2021. Similar data can be found here:http://www.qub.ac.uk/research-centres/nicr/. 

  3. Welsh data were published by the Welsh Cancer Intelligence and Surveillance Unit (WCISU), Health Intelligence Division, Public Health Wales https://phw.nhs.wales/services-and-teams/welsh-cancer-intelligence-and-surveillance-unit-wcisu/cancer-reporting-tool-official-statistics/ June 2022. 

  4. Scotland data were provided by the Scottish Cancer Registry, Public Health Scotland (PHS) on request, May 2021. Similar data can be found here: https://publichealthscotland.scot/publications/show-all-releases?id=20468

About this data

Data is for UK, 2017-2019, ICD-10 C77-C80.

Last reviewed:

Cancer of unknown primary European age-standardised (AS) Open a glossary item incidence rates for females and males combined decreased by 60% in the UK between 1993-1995 and 2017-2019.[1-4] The decrease was larger in males than in females.

For females, cancer of unknown primary AS incidence rates in the UK decreased by 58% between 1993-1995 and 2017-2019. For males, cancer of unknown primary AS incidence rates in the UK decreased by 63% between 1993-1995 and 2017-2019.

Over the last decade in the UK (between 2007-2009 and 2017-2019), cancer of unknown primary AS incidence rates for females and males combined decreased by 34%. In females AS incidence rates decreased by 35%, and in males rates decreased by 34%.

Cancer of Unknown Primary (ICD-10 C77-C80), European Age-Standardised Incidence Rates, Persons Population, 1993 to 2019

Cancer of unknown primary incidence rates have decreased overall in all broad age groups in females and males combined in the UK since the early 1990s.[1-4] Rates in 0-24s have decreased by 44%, in 25-49s have decreased by 59%, in 50-59s have decreased by 64%, in 60-69s have decreased by 68%, in 70-79s have decreased by 66% and in 80+s have decreased by 48%.

Cancer of Unknown Primary (ICD-10 C77-C80), European Age-Standardised Incidence Rates per 100,000 Persons Population, By Age, UK, 1993-2019

CUP incidence trends reflect improvements in data collection and diagnostic capabilities which mean identification of primary site is possible for more cancer cases, hence fewer cases are registered as CUP. CUP data were not consistently collected until the 1990s, meaning trends starting before this time are not reliable.

References

  1. England data were provided by the National Cancer Registration and Analysis Service (NCRAS), part of the National Disease Registration Service (NDRS) in NHS England, on request through the Office for Data Release, January 2023. Similar data can be found here: https://www.cancerdata.nhs.uk/ 

  2.  Northern Ireland data were provided by the Northern Ireland Cancer Registry (NICR) on request, October 2021. Similar data can be found here:http://www.qub.ac.uk/research-centres/nicr/. 

  3. Welsh data were published by the Welsh Cancer Intelligence and Surveillance Unit (WCISU), Health Intelligence Division, Public Health Wales https://phw.nhs.wales/services-and-teams/welsh-cancer-intelligence-and-surveillance-unit-wcisu/cancer-reporting-tool-official-statistics/ June 2022. 

  4. Scotland data were provided by the Scottish Cancer Registry, Public Health Scotland (PHS) on request, May 2021. Similar data can be found here: https://publichealthscotland.scot/publications/show-all-releases?id=20468

About this data

Data is for UK, 1993-2019, ICD-10 C77-C80.

Last reviewed:

The number of new cancers of unknown primary cases on average each year in the UK is projected to rise from around 7,500 cases in 2023-2025 to around 8,200 cases in 2038-2040.[1]

Cancers of unknown primary incidence rates are projected to fall by 13% in the UK between 2023-2025 and 2038-2040, to 9 cases per 100,000 people on average each year by 2038-2040.[1] This includes a similar decrease for males and females.

For females, cancers of unknown primary European age-standardised (AS) Open a glossary item incidence rates in the UK are projected to fall by 14% between 2023-2025 and 2038-2040, to 8 cases per 100,000 per year by 2038-2040.[1] For males, AS rates are projected to fall by 12% between 2023-2025 and 2038-2040, to 10 cases per 100,000 per year by 2038-2040.[1]

Cancers of unknown primary (C77-C80), Observed and Projected Age-Standardised Incidence Rates, by Sex, UK, 1993-2040

Download the data table (xlsx)

See also

Find out how these projections were calculated

Incidence trends over time for cancer of unknown primary

Projections of incidence for all cancers combined

Download the projections data table

References

Calculated by the Cancer Intelligence Team at Cancer Research UK, February 2023. Age-period-cohort modelling approach described here, using 2020-based population projections (Office for National Statistics) and observed cancer incidence (1975-2018 for England, Scotland and Wales, 1993-2018 for Northern Ireland).

About this data

Projections are based on incidence data from 1975-2018 (England, Scotland and Wales) and 1993-2018 (Northern Ireland); the above figure presents all UK data from 1993-2018 (observed) and 2019-2040 (projected). Number of new cases and age-standardised rates are presented as annual averages for each 3-year rolling period. ICD-10 codes C77-C80.

Projections are based on observed incidence rates and therefore implicitly include changes in cancer risk factors and diagnosis. Confidence intervals are not calculated for the projected figures. Projections are by their nature uncertain because unexpected events in future could change the trend. It is not sensible to calculate a boundary of uncertainty around these already uncertain point estimates. Changes are described as 'increase' or 'decrease' if there is any difference between the point estimates.

More on projections methodology

Last reviewed:

Some cancers of unknown primary have the location of their secondary/metastatic growth recorded. Most cancers of unknown primary in the UK do not have a specific location recorded (2016-2018).[1-4] Variation of incidence by anatomical site may reflect the physical size of each site, and differences in risk factor exposure by site, among other factors.

Download this data

Cases and percentages may not sum due to rounding

See also

Find out more about the counting and coding of this data

References

  1. Data were provided by the National Cancer Registration and Analysis Service (part of Public Health England), on request through the Office for Data Release, July 2021. Similar data can be found here: https://www.ons.gov.uk
  2. Data were provided by ISD Scotland on request, April 2020. Similar data can be found here: http://www.isdscotland.org/Health-Topics/Cancer/Publications.
  3. Data were published by the Welsh Cancer Intelligence and Surveillance Unit, Health Intelligence Division, Public Health Wales, March 2021. https://phw.nhs.wales/services-and-teams/welsh-cancer-intelligence-and-surveillance-unit-wcisu/cancer-incidence-in-wales-2002-2018/.
  4. Data were provided by the Northern Ireland Cancer Registry on request, June 2020. Similar data can be found here: http://www.qub.ac.uk/research-centres/nicr/

About this data

Data is for UK, 2016-2018, ICD-10 C77-C80. For some cases the specific location of the cancer is not recorded, this may be due to clinical or data recording factors.

Last reviewed:

Cancer of unknown primary incidence rates (European age-standardised (AS) rates Open a glossary item) in England in females are 58% higher in the most deprived quintile compared with the least, and in males are 65% higher in the most deprived quintile compared with the least (2013-2017).[1]

It is estimated that there are around 1,400 more cases of cancer of unknown primary each year in England than there would be if every deprivation quintile had the same age-specific crude incidence rates as the least deprived quintile. Around 620 of these cases are in females, and around 780 in males.

Cancer of Unknown Primary (C77-C80), Estimated Average Number of Excess Cases per Year and European Age-Standardised Incidence Rates per 100,000 Population, by Deprivation Quintile, England, 2013-2017

See also

Data table: Cancer incidence rates and excess cases by cancer type in England

Incidence by deprivation for all cancer types combined

Cancer of unknown primary mortality by deprivation  (not directly comparable with incidence by deprivation)

Cancer incidence by deprivation for Scotland

Cancer incidence by deprivation for Wales

Cancer incidence by deprivation for Northern Ireland

References

  1. Calculated by the Cancer Intelligence Team at Cancer Research UK, April 2020. Based on method reported in National Cancer Intelligence Network Cancer by Deprivation in England Incidence, 1996-2010 Mortality, 1997-2011 . Using cancer incidence data 2013-2017 (Public Health England) and population data 2013-2017 (Office for National Statistics) by Indices of Multiple Deprivation 2015 income domain quintile, cancer type, sex, and five-year age band.

About this data

Data is for England, 2013-2017, ICD-10 C21.

Last reviewed:

An estimated 12,500 people who had been diagnosed with cancer of unknown primary (CUP) between 1991 and 2010 were alive in the UK at the end of 2010.[1]

See also

Cancer of unknown primary cancer incidence statistics by sex and UK country

What is prevalence?

References

  1. Macmillan Cancer Support and National Cancer Registration and Analysis Service. Cancer Prevalence UK Data Tables. London: NCRAS; 2015.

About this data

Data is for: Great Britain (1991-2010) and Northern Ireland (1993-2010), ICD-10 C77, C78, C79, C80

Last reviewed:

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Cancer stats explained

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