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Bowel screening

Bowel screening

The issue

New Zealand has one of the highest bowel cancer age-standardised incidence rates in the world, it is currently the second most diagnosed cancer and the second leading cause of cancer-related deaths in the country[i]. Bowel cancer survival is poorer for Māori and Pacific and people living in areas of high deprivation. New Zealand has high rates of delayed diagnosis of bowel cancer, leading to poorer cancer outcomes[ii].

Population-based bowel cancer screening is an effective means of reducing both incidence and death from bowel cancer through earlier diagnosis and prompt treatment[iii][iv]. Bowel cancers almost always arise from benign polyps (growths) that can be removed if detected. Survival post-diagnosis depends on the extent of the disease, ranging from 94% 5-year net survival for early-stage bowel cancer, to 13% for advanced-stage disease[v].

Diagnosis and treatment at an early stage are critical for ensuring positive outcomes for those affected.

Bowel Screening programme

The introduction of the National Bowel Screening Programme (NBSP) in 2017-2022 was a major milestone in cancer control in Aotearoa. Population-based bowel screening saves lives. Since the screening programme began, over 1400 cancers and thousands of pre-cancerous polyps have been detected.

The Bowel Screening Programme invites New Zealanders aged 60-74 to have a free bowel screening test every 2 years. Beginning in mid-2023, Māori and Pacific peoples will be invited from age 50. The NBSP aims for 60% participation overall and is currently achieving approximately 63%. Māori and Pacific participation is lower at about 56% and 43% respectively.

The success of the bowel screening programme relies on high, sustained and equitable participation in screening.

Cancer Society recommendations

  • New Zealanders aged 60-74 years and Māori and Pacific Island peoples aged 50-74 years[vi] should complete a free bowel screening test every two years.
  • People who have bowel symptoms and who have a negative result on a screening test may still require further tests, and so should discuss their symptoms with their medical provider.
  • Anyone with symptoms of bowel cancer (including younger people) or have concerns about their risk of bowel cancer should see their health provider and not wait for a screening test to be sent to them. The most common symptoms of bowel cancer are blood in stools and anaemia. Change in bowel habit lasting for 6 weeks or more (e.g., constipation, loose stools), straining, persistent abdominal pain, cramping, vomiting and weight-loss can have many explanations including the possibility of bowel cancer. Prompt symptomatic diagnosis remains a priority as many bowel cancers are detected this way.
  • People at higher risk due to a personal or strong family history of bowel cancer or adenomatous polyps or have an inflammatory bowel disease should talk to their medical provider as tests/investigations from an earlier age may be needed.
  • For adults aged above 74 years, the decision to screen should be individualised, taking into account the patient’s overall health and preferences. The benefits of bowel screening decrease after age 75. New Zealanders in this age group are encouraged to discuss screening with their medical provider.
  • Primary prevention: a diet high in dietary fibre, lower in processed and red meat, no or less alcohol, avoiding tobacco, being active and a healthy weight may reduce the risk of bowel cancer.

The Cancer Society recommends the following policy interventions and health system improvements:

  • That bowel cancer screening age eligibility is extended to people aged 50-59. We previously called for the Government to prioritise Māori and Pacific peoples in this age group to address current inequities in the programme, and we acknowledge that the Government is proceeding with this age expansion beginning in 2023. We continue to urge the Government for a commitment to roll out screening to all New Zealanders aged 50-59 by a set time.
  • Ensure the implementation of targeted, proven strategies to reduce disparities in screening participation, including awareness campaigns.
  • Identify and address factors that inhibit the pathway to diagnosis and treatment, including appropriate referral of at-risk patients, barriers to collaboration between primary and secondary health services, lengthy diagnostic delays, limited availability of diagnostic services, workforce shortages, and difficulty in accessing specialists.

References

[i] Te whatu Ora Health New Zealand New Cancer Registrations 2020

[ii] Sharples KJ, Firth MJ, Hinder VA, et al. The New Zealand PIPER Project: colorectal cancer survival according to rurality, ethnicity and socioeconomic deprivation-results from a retrospective cohort study. NZ Med J. 2018; 131(1476):24-39.

[iii] Heresbach D, Manfredi S, D'Halluin P, et al. Review in depth and meta-analysis of controlled trials on colorectal cancer screening by faecal occult blood test. European Journal of Gastroenterology & Hepatology 2006; 18(4):p 427-433.

[iv] Hewitson P, Glasziou P, Irwig L, et al. Screening for colorectal cancer using the faecal occult blood test, Hemoccult. Cochrane Database Syst Rev. 2007; 2007(1):CD001216.

[v] Araghi M, Arnold M, Rutherford MJ, et al Colon and rectal cancer survival in seven high-income countries 2010–2014: variation by age and stage at diagnosis (the ICBP SURVMARK-2 project) Gut 2021;70:114-126.

[vi] Age eligibility for free bowel screening will be widened to include Māori and Pacific Island peoples from 50 years in mid-2023 https://www.nsu.govt.nz/health-professionals/national-bowel-screening-programme/lowering-age-eligibility-m%C4%81ori-and-pacific