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Cancer of unknown primary site in Australia

The following material has been sourced from the Australian Institute of Health and Welfare

Cancer of unknown primary site incorporates ICD-10 cancer code C80 (Malignant neoplasm without specification of site).


Estimated number of new cases of cancer of unknown primary site diagnosed in 2017

2,555 = male 1,346 males + Female icon PNG 1,209 females


unknown-primary-site-percent-all-new-cases

Estimated % of all new cancer cases diagnosed in 2017

1.9%


Estimated number of deaths from cancer of unknown primary site in 2017

2,830 = male 1,369 males + Female icon PNG 1,461 females


unknown-primary-site-percent-all-deaths

Estimated % of all deaths from cancer in 2017

5.9%


13-in-100

Chance of surviving at least 5 years (2009–2013)

13%


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People living with cancer of unknown primary site at the end of 2012 (diagnosed in the 5 year period 2008 to 2012)

2,917


New cases of cancer of unknown primary site

Cancer of unknown primary site was the 11th most commonly diagnosed cancer in Australia in 2013. It is estimated that it will become the 14th most commonly diagnosed cancer in 2017.

In 2013, there were 2,704 new cases of cancer of unknown primary site diagnosed in Australia (1,416 males and 1,288 females). In 2017, it is estimated that 2,555 new cases of cancer of unknown primary site will be diagnosed in Australia (1,346 males and 1,209 females).

In 2013, the age-standardised incidence rate was 10 cases per 100,000 persons (12 for males and 8.6 for females). In 2017, it is estimated that the age-standardised incidence rate will be 8.5 cases per 100,000 persons (10 for males and 7.3 for females). From age group 40–44, the incidence rate of cancer of unknown primary site is expected to generally increase with age (Figure 1).

In 2017, it is estimated that the risk of an individual being diagnosed with cancer of unknown primary site by their 85th birthday will be 1 in 94 (1 in 78 males and 1 in 114 females).

The number of new cases of cancer of unknown primary site diagnosed increased from 2,140 (1,117 males and 1,023 females) in 1982 to 2,704 in 2013. Over the same period, the age-standardised incidence rate decreased from 18 cases per 100,000 persons (21 for males and 15 for females) in 1982 to 10 cases per 100,000 persons in 2013 (Figure 2).

Deaths from cancer of unknown primary site

In 2014, cancer of unknown primary site was the 6th leading cause of cancer death in Australia. It is estimated that it will remain the 6th most common cause of death from cancer in 2017.

In 2014, there were 2,495 deaths from cancer of unknown primary site in Australia (1,284 males and 1,211 females). In 2017, it is estimated that this will increase to 2,830 deaths (1,369 males and 1,461 females).

In 2014, the age-standardised mortality rate was 9.0 deaths per 100,000 persons (10 for males and 7.8 for females). In 2017, it is estimated that the age-standardised mortality rate will be 9.3 deaths per 100,000 persons (10 for males and 8.7 for females). From age group 40–44, the mortality rate of cancer of unknown primary site is expected to generally increase with age (Figure 1).

In 2017, it is estimated that the risk of an individual dying from cancer of unknown primary site by their 85th birthday will be 1 in 80 (1 in 75 males and 1 in 84 females).

The number of deaths from cancer of unknown primary site increased from 574 (291 males and 283 females) in 1968 to 2,495 in 2014. Over the same period, the age-standardised mortality rate increased from 6.8 deaths per 100,000 persons (7.7 for males and 6.1 for females) in 1982 to 9.0 deaths per 100,000 persons in 2014 (Figure 2).

Figure 1: Estimated age-specific incidence and mortality rates for cancer of unknown primary site, by sex, 2017

unknown-primary-site-cancer-fig1

Source: AIHW [1].

Figure 2: Age-standardised incidence rates for cancer of unknown primary site 1982–2013 and age-standardised mortality rates for cancer of unknown primary site 1968–2014, by sex

unknown-primary-site-cancer-fig2

Source: AIHW [2].

Survival from cancer of unknown primary site

In 2009–2013, individuals diagnosed with cancer of unknown primary site had a 13% chance of surviving for 5 years compared to their counterparts in the general Australian population.

Between 1984–1988 and 2009–2013, 5-year relative survival from cancer of unknown primary site improved from 6.2% to 13%.

Figure 3: 5-year relative survival from cancer of unknown primary site, by sex, 1984–1988 to 2009–2013

unknown-primary-site-cancer-fig3

Source: AIHW [1].

Survivorship population for cancer of unknown primary site

The survivorship population is measured using prevalence data. Prevalence refers to the number of people alive who have previously been diagnosed with cancer of unknown primary site.

The prevalence for 1, 5 and 31 years given below are the number of people living with cancer of unknown primary site at the end of 2012 who had been diagnosed in the preceding 1, 5 and 31 years respectively.

At the end of 2012, there were 1,084 people living who had been diagnosed with cancer of unknown primary site that year, 2,917 people who had been diagnosed with cancer of unknown primary site in the previous 5 years (from 2008 to 2012) and 6,745 people who had been diagnosed with cancer of unknown primary site in the previous 31 years (from 1982 to 2012).


Data notes

International Statistical Classification of Diseases and Related Health Problems Version 10 (ICD–10)

Cancer is classified by the International Statistical Classification of Diseases and Related Health Problems Version 10 (ICD–10). This is a statistical classification, published by the World Health Organization, in which each morbid condition is assigned a unique code according to established criteria.

Estimations

Future estimations for incidence and mortality are a mathematical extrapolation of past trends. They assume that the most recent trends will continue into the future, and are intended to illustrate future changes that might reasonably be expected to occur if the stated assumptions continue to apply over the estimated period. Actual future cancer incidence and mortality rates may vary from these estimations. For instance, new screening programs may increase the detection of new cancer cases; new vaccination programs may decrease the risk of developing cancer; and improvements in treatment options may decrease mortality rates.

Incidence

Cancer incidence indicates the number of new cancers diagnosed during a specified time period (usually one year).

The 2013 national incidence counts include estimates for NSW because the actual data were not available. Note that actual data for the Australian Capital Territory do not include cases identified from death certificates.

The 2017 estimates are based on 2004–13 incidence data. Due to rounding of these estimates, male and female incidence may not sum to person incidence.

Mortality

Cancer mortality refers to the number of deaths occurring during a specified time period (usually one year) for which the underlying cause of death is cancer.

The 2017 estimates are based on mortality data up to 2013. Joinpoint analysis was used on the longest time series of age–standardised rates available to determine the starting year of the most recent trend.

Prevalence

Prevalence of cancer refers to the number of people alive with a prior diagnosis of cancer at a given time. It is distinct from incidence, which is the number of new cancers diagnosed within a given period of time. The longest period for which it is possible to calculate prevalence using the available national data (from 1982 to 2012) is currently 31 years so this is used to provide an estimate of the ‘total’ prevalence of cancer as at the end of 2012, noting that people diagnosed with cancer before 1982 aren’t included.

Age standardised rates

Incidence and mortality rates expressed per 100,000 population are age–standardised to the Australian population as at 30 June 2001.

References

  1. Australian Institute of Health and Welfare 2017. Australian Cancer Incidence and Mortality (ACIM) books: Cancer of unknown primary site. Canberra: AIHW. www.aihw.gov.au/acim-books [Accessed February 2017].
  2. AIHW 2017. Cancer in Australia 2017. Cancer series no. 101. Cat. No. CAN 100. Canberra: AIHW.