Australian Doctor 14th March 2025 | Page 36

screening modality they should

consider using .

COLORECTAL CANCER SCREENING OPTIONS

THERE are several colorectal cancer

screening choices that Australian GPs can recommend to their patients . In 2021 , the United States Preventive Services Task Force ( USPSTF ), arguably the leading global scientific preventive health organisation , published its updated recommendations regarding six different and acceptable colorec-

Australian Government Department of Health and Aged Care

Figure 1 . National Bowel Cancer Screening Program .

colonoscopy is so successful at reducing the colorectal mortality rate — it both visualises and removes ‘ occult ’ premalignant lesions at the same time .

The occult nature of colorectal polyposis transitioning to colorectal cancer is hidden and is a major contributor to the lethal nature of the condition . This is why ‘ shining the light ’ during a colonoscopy to expose what is happening in the dark world of the colorectum is such a successful strategy in eliminating colorectal polyposis , thereby dramatically lessening the mortality rate from colorectal cancer .

tal cancer screening pathways ( see box 1 ). 7 The USPSTF currently regards all six options as equivalent and accept-

To complement the removal of colorectal polyps , and to ensure that a high standard of colonoscopic pol-

able colorectal cancer screening path-

ypectomy is achieved , all colonos-

ways for appropriately aged and

copists in Australia should now be

eligible people to consider .

audited on a three-yearly cycle . This is

The National Bowel Cancer Screen-

to ensure that they meet the required

ing Program ( NBCSP ) rolled out by the

benchmarks for colonoscopic pol-

Australian Government Department

ypectomy . The current Gastroenter-

of Health and Aged Care is the current

ological Society of Australia ( GESA )

mainstay of colorectal cancer screening across Australia . 8 Eligible men and women aged 50-74 are sent a FOBT kit

audit requirements , supported by the Royal Australasian College of Surgeons ( RACS ) and the Conjoint Committee of

every two years after their 50th birth-

GESA and RACS , are that colonosco-

day , and Australians aged between 45

pists need to demonstrate a minimum

and 50 are now being encouraged to

95 % caecal intubation rate ( the cur-

contact the NBCSP directly , as they

rent national average is around 98 %),

are now eligible to commence FOBT

a minimum 25 % adenoma detec-

screening from this younger age .

tion rate ( the current national aver-

The NBCSP has been a tremen-

age is around 45 %) and a minimum

dous advance in Australia , and this

4 % sessile serrated lesion excision

article in no way means to under-

rate ( the current national average is

mine the uptake or functioning of this

around 14 %). 13

important government-funded initi-

Complications can occur during

ative . Further , the MBS clearly states

colonoscopy , such as post-polypec-

in Technical Note 8.152 that “ general

tomy major bleeding and colonos-

practitioners are urged to recommend

copic perforation ( both should occur

biennial FOBT screening to age-appropriate patients ”. 9 However , there is a current Australian participation

in less than 1:3000 colonoscopies ). These complications are not currently nationally audited . However ,

rate of around 40 %, such that Bowel

GPs may be reassured that creden-

Cancer Australia — a leading national

tialled colonoscopy practitioners can

Australian charity dedicated to prevention , early diagnosis , research , quality treatment and care in colorec-

Figure 2 . Colorectal cancer .

safely achieve very high polypectomy rates . This is an important GESA standard to which almost all Austral-

tal cancer — has recently published its

ian colonoscopists adhere , and this is

concerns regarding the stagnating rate of colorectal cancer screening in Australia . 10 , 11 Therefore , one of the aims of this How To Treat article is to further encourage GPs to recommend to their patient populations that they partake in the NBCSP , as the authors agree with Bowel Cancer Australia that participation rates are stagnating .

SCREENING COLONOSCOPY FOR COLORECTAL CANCER

The Level 1A evidence

THERE are currently four large prospective

randomised trials inves-

Box 1 . USPSTF colorectal cancer screening options

1 . High-sensitivity guaiac faecal occult blood test ( HSgFOBT ) or faecal immunochemical test ( FIT ) every year . 2 . Stool DNA-FIT every 1-3 years . 3 . Computed tomography colonography ( see figure 4 ) every five years .

4 . Flexible sigmoidoscopy every five years .

5 . Flexible sigmoidoscopy every 10 years plus annual FIT . 6 . Colonoscopy screening every

10 years .

was 0.50 ( 95 % CI , 0.27 to 0.77 ). In other words , screening colonoscopy achieved a 50 % reduction in colorectal cancer mortality in NordICC , in those who had a colonoscopy , as confirmed in a New England Journal of Medicine 2022 editorial . 5 Also of relevance is the UKFSST . 6 This trial published its 17-year follow-up of 40,621 randomised patients who received a screening flexible sigmoidoscopy . In per-protocol analyses , adjusted for non-compliance , colorectal cancer incidence and mortality were 35 % ( HR 0 · 65 [ 95 % CI 0 · 59 – 0 · 71 ]) and 41 % ( 0 · 59 [ 0 · 49 – 0 · 70 ]) lower in the screened group . In addition , distal colorectal

each year could be prevented if a single colonoscopy was performed in every Australian between the ages of 55 and 64 .

How does screening colonoscopy result in a 50 % reduction in colorectal cancer mortality ?

Examining the colon with a colonoscope

does not in itself reduce the risk of death from colorectal cancer . However , when asymptomatic precancerous adenomatous polyps ( see figure 5 ) are seen and removed during a colonoscopy via a colonoscopic polypectomy , these polyps then cannot progress to form inva-

the international benchmark required for achieving the 50 % reduction in colorectal cancer mortality that was shown in the NordICC trial .

THE MEDICAL BOARD OF AUSTRALIA

THE 2020 Good Medical Practice : a

Code of Conduct for Doctors in Australia “ describes what is expected of all doctors registered to practise medicine in Australia ”. 14 Section 3.2 of the code encourages us all to provide good patient care ( see box 2 ).

Screening colonoscopy as a primary modality for colorectal cancer

tigating the utility of screening colonoscopy in normal risk populations . These are the Nordic-European Initiative on Colo rectal Cancer trial

Source : United States Preventive Services Task Force 2021 7

cancer mortality was reduced by 66 % ( HR 0 · 34 [ 95 % CI 0 · 26 – 0 · 46 ]).

Both the 66 % left-sided colorectal mortality reduction seen at 17 years

sive colorectal cancer . The adenoma to carcinoma sequence is well established and accepted as the principal cause in the

screening is now an internationally recognised screening technique that is used by many in Australia today . However , opinion varies between the

( NordICC trial ), the CONFIRM ,

colorectal cancer and related death . In

of follow-up in the UKFSST , and the

development of colorectal cancer ,

various Australian stakeholders as

COLONPREV and SCREESCO colonos-

NordICC , 11,843 randomised patients

50 % reduction in left- and right-sided

although primary cancers can arise de

to the role of colonoscopy as the pri-

copy screening trials . Of these , only

underwent colonoscopy screening ,

colorectal cancer mortality seen at 10

novo in a small percentage of people .

mary modality in colorectal cancer

NordICC has completed and published

with 15 participants having major

years in the NordICC trial , are highly

The removal of benign polyps to

screening .

its 10-year findings .

bleeding after polyp removal , and with

significant percentages . These colorec-

prevent cancer from forming is not

As authors and practitioners , we

The NordICC colonoscopy colorec-

no perforations or screening-related

tal cancer mortality reduction figures

unique to the colorectum . For exam-

consider that we need to follow good

tal cancer screening study was a prag-

deaths occurring within 30 days after

( 66 % and 50 %) are in stark contrast

ple , it is well accepted that if ductal car-

medical practice , which in essence

matic , randomised trial involving men

colonoscopy .

to the 16 % colorectal cancer mortal-

cinoma in situ ( DCIS ) in the breast is

means we believe our patients

and women aged 55-64 drawn from

During a median follow-up of

ity reduction reported in the 2007

surgically removed , then there is a cor-

deserve to know the Level 1A evi-

population registries in Poland , Norway , Sweden and the Netherlands between 2009 and 2014 . The partic-

10 years , the adjusted analyses in NordICC showed that for the participants who were randomly assigned

Cochrane Review of colorectal cancer screening using faecal occult blood testing . 12

responding decline in subsequent invasive breast cancer . In addition , removal of Hutchinson melanotic freckles pre-

dence . In this instance , this means taking note of the growing Level 1A evidence that colonoscopic colorec-

ipants were randomly assigned in a

to and had undergone screening colo-

There are currently in excess of

vents the development of melanoma .

tal cancer screening has a significant

1:2 ratio to either receive an invita-

noscopy , their risk of colorectal can-

5000 Australians who succumb to

However , unlike skin cancer precursors

benefit in terms of mortality reduc-

tion to undergo a single screening

cer at 10 years decreased from 1.22 %

colorectal cancer each year . If one then

that are easily visible to the naked eye ,

tion from colorectal cancer ( that is ,

colonoscopy ( the invited group ) or

to 0.84 %, and the risk of death from

applies this prospective randomised

the detection of precancerous colorec-

“ a clinically recognised treatment ”).

to receive no invitation for screening

colorectal cancer was 0.15 % in the

international screening data to the

tal polyps requires some form of imag-

Given the recent Level 1A scientific

( the usual-care group ). The primary

invited group and 0.30 % in the usu-

Australian population , more than 2500

ing , visualisation or stool testing . This

evidence quoted earlier from the Nor-

end points were the group risks of

al-care group . The estimated risk ratio

unnecessary colorectal cancer deaths

is the principal reason why screening

dICC and UKFSST studies ,

PAGE 38