Colorectal cancer screening in Australia

Question 1

Colorectal cancer screening in Australia

1 Colorectal cancer (CRC) is the second most common cancer, after breast cancer, in Australia
After lung cancer, it is the second most common cause of cancer death.

Question 2

CRC has a precancerous stage in the form of a polyp, which acquires mutations through one of three molecular pathways to become an invasive lesion

Question 3

Tools used to screen for colorectal cancer

Question 4

The current guidelines suggest using a faecal occult blood test (FOBT), which aims to identify microscopic blood in the stool, as the first-line screening test to detect CRC

Question 5

the immunochemical form (iFOBT)

Question 6

The iFOBT uses an antibody reaction to specifically identify the human haemoglobin

Question 7

41,000 of the population screened had a positive faecal occult blood test (FOBT) – 8% positivity rate

Question 8

Of the patients with positive FOBT, 58% will have normal colonoscopy, 39% will be diagnosed with a polyp and only 3% will be diagnosed with cancer or suspected cancer

Question 9

Risk factors for positive FOBT screening included: male gender, first screening, older ages, remote communities, low socioeconomic status and Aboriginal or Torres Strait Islander background

Question 10

The current recommended strategy for population screening in Australia is an iFOBT every two years in asymptomatic individuals, starting from age 50 years to age 74 years.

Question 11

Category 1
(relative risk x 1–2)
Asymptomatic people who have:
no personal history of bowel cancer, colorectal adenomas, inflammatory bowel disease or family history of colorectal cancer (CRC)
OR
one first-degree relative with CRC diagnosed at 55 years or older
OR
one first-degree and one second-degree relative with CRC diagnosed at 55 years or older.

Question 12

Category 2
(relative risk x 3–6)
Asymptomatic people who have:
one first-degree relative with CRC diagnosed before age 55 years
OR
two first-degree relatives with CRC diagnosed at any age
OR
one first-degree relative and at least two second-degree relatives diagnosed with CRC at any age.

Question 13

Category 3
(relative risk x 7–10)
Asymptomatic people who have:
at least three first-degree or second-degree relatives with CRC, with at least one diagnosed before age 55 years
OR
at least three first-degree relatives with CRC diagnosed at any age.

Question 14

age of commencing
screening in patients with a family history
recommendations for the use of aspirin

Question 15

There is level 1 evidence to suggest that regular consumption of aspirin can reduce incidence and mortality in CRC
reduce the occurrence of CRC by 24% and reduce CRC-associated mortality by 35% after 10 years of taking

Question 16

Category 1 (relative risk x 1–2)
Immunochemical faecal occult blood test (iFOBT) should be considered every two years from age 45 years, given the risk of colorectal cancer at this age is approximately equivalent to the population risk at age 50 years
For patients aged 50–70 years, low-dose aspirin (100 mg) daily should be considered

Question 17

Category 2 (relative risk x 3–6)
iFOBT should be performed every two years from age 40 to 50 years
Colonoscopy should be performed every five years from age 50 to 74 years. Computed tomography (CT) colonography can be offered if colonoscopy is contraindicated
Low-dose (100 mg) aspirin daily should be considered
As a result of the possibility of Lynch syndrome, a complete family history should be taken and updated regularly, and the accuracy of the cancer diagnoses and polyp pathology should be checked carefully
Genetic testing is not appropriate at present for people with category 2 risk

Question 18

Category 3 (relative risk x 7–10)
iFOBT should be performed every two years from age 35 to 45 years
Five-yearly colonoscopy from age 45 to 74 years. CT colonography can be offered if colonoscopy is contraindicated
Low-dose (100 mg) aspirin daily should be considered
Referral to a genetic centre for hereditary cancer syndromes should be considered

Question 19

CRC remains a huge health burden in Australia, and screening is vital in reducing mortality.4 The major limitation in the screening program is the low participation rate.10 GPs have a crucial role in the success of screening by facilitating participation in the screening program. Screening of patients with symptoms is inappropriate. Instead, these patients should be referred for investigation of their symptoms. Determining the patient’s risk, providing education, encouraging screening and instituting prompt referrals are essential in reducing CRC morbidity and mortality. The updated guidelines provide clear guidance regarding the current screening recommendations and suggest biennial screening between the ages of 50 and 74 years. The use of low-dose aspirin should now be discussed with all patients aged 50–70 years as a form of chemoprophylaxis. Individuals with a family history of CRC will need to start screening at an earlier age on the basis of category of risk. Further details regarding screening and management of CRC can be found on the Cancer Council Australia website (https://wiki.cancer.org.au/australia/Guidelines:Colorectal_cancer).

Competing interests: None.

Question 20

For appendiceal carcinoids ≤2 cm and confined to the appendix treated by simple appendectomy, no follow-up is required.
For larger or node-positive tumors treated by right hemicolectomy, between 3 and 12 months postresection

Answer 20

A. Pain is elicited during Dre in pelvic and subileal appendicitis

Question 21

Biennial faecal occult blood test (FOBT) can reduce colorectal cancer (CRC) mortality by 16%.

Answer 21

superseded by the more sensitive and specific

faecal immunochemical test.

Question 22

FOBT is recommended for the asymptomatic (average risk)

population from 50 years of age every two years (A) until 75 years of age with repeated negative findings

Answer 22

Increased risk is determined by family history; this should include determining the number of relatives affected by
CRC,side of family and age at diagnosis

Question 23

Colonoscopy is not recommended as a screening test for people at average risk of CRC

Answer 23

Colonoscopy has indirect and direct harms, including, rarely, death from the procedure

Question 24

Harm may be caused by the bowel cleanout prior to the procedure (eg
dehydration and electrolyte imbalances), the sedation used during the procedure (eg cardiovascular events), or
the procedure itself (eg infection, colonic perforations, bleeding).

Question 25

Category 1 – Average or slightly

increased risk:

Answer 25

Asymptomatic people with:
• no personal history of bowel cancer,
colorectal adenomas, inflammatory bowel
disease or family history of colorectal cancer
(CRC)
or
• one first-degree or second-degree relative
with CRC diagnosed aged ≥55 years

Question 26

Faecal occult blood test
(FOBT; I, A)
Every two years from
50 years of age
(Practice Point)

Question 27

Category 2 – Moderately increased risk

(1–2% of the population):

Answer 27

Asymptomatic people with:
• one first-degree relative with CRC diagnosed
aged <55 years
or
• two first-degree or one first-degree and one
second-degree relative(s) on the same side
of the family with CRC diagnosed at any age
(without potentially high-risk features as in

Question 28

Colonoscopy
Sigmoidoscopy plus
double-contrast barium
enema or computed
tomography (CT)
colonography (performed
by an experienced
operator) are acceptable
if colonoscopy is
contraindicated
Consider offering FOBT
(III, B)
Every five years from
50 years of age, or
at an age 10 years
younger than the age
of first diagnosis of
CRC in the family,
whichever comes first
(Practice Point)
In intervening years

Question 29

Category 3 – High risk
(relative risk of ~4–20%; <1% of the
population):*

Answer 29

Asymptomatic people with:
• three or more first-degree or seconddegree
relatives on the same side of the
family diagnosed with CRC (suspected
Lynch syndrome, also known as hereditary
non-polyposis CRC [HNPCC]or other Lynch
syndrome-related cancers†
or
• two or more first- or second-degree relatives
on the same side of the family diagnosed
with CRC, including any of the following
high-risk features:
–– multiple CRC in the one person
–– CRC aged <50 years
–– a family member who has or had Lynch
syndrome-related cancer
or
• at least one first-degree or second-degree
relative with CRC, with a large number
of adenomas throughout the large bowel
(suspected familial adenomatous polyposis
[FAP])

Question 30

Refer for genetic screening
of affected relatives
Refer to bowel cancer
specialist to plan
appropriate surveillance
(III, B)
FAP: flexible
sigmoidoscopy
or
Colonoscopy in
attenuated FAP‡

Answer 30

HNPCC:
– colonoscopy
Consider offering FOBT

Question 31

Those at risk for:
• FAP (no APC
mutation defined):
Every 12 months
from 12–15 to
30–35 years of age
and every three
years after 35 years
of age#
• Lynch syndrome:
one to two yearly
from 25 years of
age or five years
earlier than the
youngest affected
member of the
family (whichever is
earliest)
Aspirin 100 mg/day is
effective prophylaxis§
In intervening years
(Practice Point)
25, 26
*