Young Australians - Cancer Epidemiology

The following information regarding cancer and young people is provided through The Australian Institute of Health and Welfare, Australia's national health and welfare statistics and information agency. The report is titled:

'Young Australians: Their health & wellbeing 2007'

• Cancer

  Cancer is a common term used to describe a range of diseases in which cells become abnormal, grow in an uncontrolled way and form a mass called a neoplasm or a tumour. Tumours can be benign (not cancerous) or malignant (cancerous). Benign tumours do not spread to other parts of the body, although they may interfere with other areas of the body as they expand. A malignant tumour is characterised by its ability to spread to other parts of the body through a process known as metastasis. Cancers can develop from most cell types in the body and are usually classified according to their organ or tissue of origin and histological features.

  The cancers that most commonly affect young people are different to those that affect adults. While the most common cancers among young people are melanoma, Hodgkin's disease and cancer of the testis, the leading cancers among adults are colorectal cancer, breast cancer and prostate cancer (AIHW & AACR 2004).
  

  Cancer is a major cause of morbidity and death in Australia, but fortunately, cancer incidence among young people remains relatively uncommon compared to the general population. Despite this, cancer was the sixth overall leading cause of disease burden among those aged 15-24 years in Australia in 2003, accounting for an estimated 4,456 DALYs (2% of total DALYs). Cancer accounted for an estimated 9% of years of life lost due to premature mortality, and less than 1% of years of 'healthy' life lost due to poor health or disability (Begg et al. 2007).

• Cancer incidence

  Information on cancer incidence and survival rates is derived from the AIHW National Cancer
  Statistics Clearing House (NCSCH). Complete incidence data on non-melanoma skin cancers (NMSC)
  are not routinely collected by state and territory cancer registries as they are not legally notifiable.

  Cancer incidence in young people aged 12-24 years, 1993-2002:
  

  • In 2002, there were 943 new cancers diagnosed in young people - a rate of 27 per 100,000 young people. Just over half (51%) of new cancers were reported in males.
  • Between 1993 and 2002, the annual incidence rate increased by 10% (24 to 27 per 100,000 young people), with the rates being slightly higher for males than for females over this period.

  The cancer with the highest incidence rate throughout the period 1993-2002 was melanoma.
  However, between 1993-97 and 1998-2002, the rate of melanoma incidence decreased by 23% for males (from 7.6 to 5.9 per 100,000 young people) and by 14% for females aged 12-24 years (from 9.1 to 7.8 per 100,000 young people).
  

  Cancer incidence rates for young people aged 12-24 years, 1993-2002:
  

  • Cancer incidence rates increased with age. In 2002, the rate for those aged 15-19 years was 1.8 times as high as the 12-14 year age group (25 compared to 14 per 100,000 young people). The rate for those aged 20-24 years (37 per 100,000 young people) was almost 3 times as high when compared to those aged 12-14 years.
    
  • Overall, 52% of new cancers diagnosed among young people in 2002 were in those aged 20-24 years.

  

  • Melanoma was the most common type of new cancer diagnosed among young people in 2002, with 251 diagnoses (30% of all new cancers). Hodgkin's disease accounted for 11% (103 diagnoses), while cancer of the testis and leukaemia both accounted for 9% of all new cancers diagnosed (86 and 85 respectively).
  • Melanoma, Hodgkin's disease and cancer of the thyroid were more common among females compared to males, while more males were diagnosed with non-Hodgkin's lymphoma and leukaemia. Incidence rates for melanoma, cancer of the testis and Hodgkin's disease for young people increased with age, while rates for leukaemia decreased.

• Hospital separations due to cancer

  In 2004-05, there were 4,995 hospital separations among those aged 12-24 years with a principal diagnosis of cancer—a rate of 138 per 100,000 young people (ICD-10-AM codes C00-C96). This does not include separations for radiotherapy or chemotherapy. This represented less than 1% of the total number of hospital separations for young people. Of these separations, 54% were for males, and male separation rates for cancer were consistently higher than for females over the period from 1996-97 to 2004-05. For young males, the highest separation rate occurred among those aged 15-19 years, whereas for young females the rate was highest among those aged 12-14 years. Between 1996-97 and 2004-05, there was no statistically significant change in the hospital separation rate for males or females.

• Deaths due to cancer

  Cancer deaths in young people aged 12-24, 1995-2004
  
  

  • In 2004, there were 144 deaths from cancer among young people (4 deaths per 100,000 young people), accounting for 10% of all deaths in this age group.
    
  • Between 1995 and 2004, there was an average annual percentage decrease of 1.6% in death rates due to cancer. In Australia and internationally, improvements in cancer outcomes for young people have been lagging behind advances achieved for children and older adults, resulting in lower reductions in mortality than in other age groups.
    

  Young males aged 12-24 years were 1.3 times as likely to die from cancer than young females, with the greatest difference occurring in the 20-24 year age group (2.6 times as high in males than females). Death rates due to cancer increased with age, consistent with the risk of cancer increasing with age (AIHW & AACR 2004).

  In 2004, the most common cancers causing death among young people were brain cancer (28 deaths), followed by unspecified cancer of bone and articular cartilage (20 deaths), and myeloid leukaemia and unspecified non-Hodgkin's lymphoma (both 12 deaths). These cancers have been consistently among the most common cancers causing death over the 10-year period from 1995 to 2004, and are consistent with the lower 5-year relative survival for these cancers compared with other cancers (see the next section for an explanation of relative survival).

• Cancer survival

  Survival rates after a diagnosis of cancer can be used to assess the effectiveness of early cancer detection and treatment. Relative survival is the ratio between the observed survival rate among a group of people with cancer and the expected survival rate among the same group had they not been diagnosed with cancer. For example, a relative survival of 100% indicates that the disease has made no difference to survival of the group over a given period. A survival rate less than 100% indicates that cancer did reduce survival compared to the population without cancer.

  Five-year relative survival rates are presented in this report for those aged 10-24 years due to data availability. The most recent available data for five-year relative survival rates are for 1992-97.

  Five-year relative survival rates for cancers affecting young people aged 10-24 years between 1982-86 and 1992-97 (per cent)
  

  • Five-year relative survival rates for all cancers in young people aged 10-24 years increased between 1982-86 and 1992-97, from 72% to 81% for males and from 82% to 85% for females.
  • In 1992-97, five-year relative survival was highest among young people with thyroid cancer (99%), malignant melanoma (97%), cancer of the testis (94%) and Hodgkin's disease (94%).
  • In 1992-97, five-year relative survival was lowest among young people with leukaemia (54%), bone cancer (61%) and brain cancer (69%).
    
  • Between 1982-86 and 1992-97, the greatest improvements in survival were for young people with leukaemia, bone cancer, Hodgkin's disease and brain cancer.

  Over the period 1982-86 and 1992-97, survival rates were highest (over 85%) for females aged 20-24 years. The improvement in survival rates was greatest for males aged 10-14 years and least for females aged 20-24 years. Relatively high improvements in survival rates were also experienced by males aged 20-24 years and females aged 10-14 years.