History, development and future of cancer screening in Australia.

INTRODUCTION: The aim of screening an asymptomatic population for cancer is to achieve better health outcomes, particularly a population survival benefit. Australia has three population screening programs: the National Cervical Screening Program (NCSP), BreastScreen Australia and the National Bowel Cancer Screening Program (NBCSP).

METHODS: We reviewed the history and development of the three programs. NCSP: Women have a Pap smear every 2 years from age 18-20, or 2 years after first becoming sexually active, until age 69. Since introduction of the NCSP, the cervical cancer incidence has halved, with an approximate 60% decrease in mortality. The screening participation rate approximates 57%, but is lower for Aboriginal and Torres Strait Islander women, women in remote areas, and women with lower socio-economic status. The National HPV (human papillomavirus) Vaccination Program, introduced in 2007, is expected to reduce the incidence of cervical cancer by a further 70% and has already reduced the incidence of high-grade lesions in girls. In 2017, testing for HPV every 5 years starting at age 25 will replace the Pap smear as the principal screening test. BreastScreen Australia: This program targets women aged 50-74. Over 20 years, mortality from breast cancer has decreased by 32% in response to screening and treatment advances. The participation rate is 56%. The major adverse impact of breast screening is overdiagnosis, estimated in Australia to be as low as 8% of detected cancers, but with estimates of up to 30% from some research. Women should be made aware of both the potential benefits and harms from screening. Genetic testing for BRCA1 and BRCA2 mutations in high-risk women leads to earlier screening.

NBCSP: The NBCSP uses immunochemical faecal occult blood test (iFOBT) kits on stool samples to detect bleeding from the bowel. When rollout is complete in 2020, test kits will be sent every 2 years to people aged 50-74. People who test positive are followed up with a colonoscopy. The participation rate is currently 37%. The positivity rate is 7%, and stage 1 bowel cancer presentations have tripled since the program began.

CONCLUSIONS: Research needs to focus on reducing mortality through increased screening participation and, in the future, obtaining guidance for customised screening from genomic testing.