Study Points to Overstatement of Lifetime Risk of Cancer

New research published in the Medical Journal of Australia indicates that the likelihood of developing a variety of common cancers is lower than is typically estimated. PCHSS investigator Professor Paul Glasziou and colleagues have concluded that, because the prevailing method does not take into account a person’s chances of dying from other, non-cancer causes, lifetime cancer risks have been overstated.

The study found that the five most common cancers in Australia – breast cancer, prostate cancer, colorectal cancer, melanoma of the skin, and lung cancer – all have lower lifetime risks in the “competing mortality” model than in the standard single-mortality method employed by the Australian Institute of Health and Welfare (AIHW). The differences were as follows:

  • Breast cancer: 12.7% → 12.1%
  • Prostate cancer – 18.7% → 16.2%
  • Colorectal cancer (men): 9.0% → 7.0%
  • Colorectal cancer (women): 6.4% → 5.5%
  • Melanoma (men): 7.5% → 6.0%
  • Melanoma (women): 4.4% → 4.0%

Speaking to the Sydney Morning HeraldRichard Juckes of the AIHW noted that the organisation knew of the alternative methodology and its advantages, but emphasised that the single-mortality method is the worldwide standard and is used to facilitate international comparisons.

Speaking to newsGP, Professor Glasziou stated, “It’s not that the figures have been hugely inaccurate, but people quote them – so we think they need to be corrected to appropriately take into account the competing risks.”

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