New Zealand has one of the highest rates of bowel cancer incidence in the world, and it is one of the leading causes of
cancer mortality, second only to lung cancer.1 In 2018 there were 3,189 new cases of bowel cancer* registered
in New Zealand equating to a rate of approximately 40 per 100,000 population, compared with 100 per 100,000 for breast cancer
in women and 109 for prostate cancer in men.2 However, the rate of death from bowel cancer is higher than for
breast or prostate cancer.3 Provisional data for 2017† shows that there were 1,229 deaths from bowel
cancer,** a rate of 14.2 deaths per 100,000 – 17.3 for men, 11.6 for women.1
Although fewer cases of bowel cancer are registered in Māori and Pacific peoples than other ethnic groups there are differences
in the treatments received and in mortality.4, 5
Five-year cancer-specific and all-cause survival for people aged < 75 years in New Zealand with bowel cancer is approximately
66% and 62%, respectively.6 A recent paper examined the patient demographics, tumour characteristics and survival
outcomes for 29,221 patients with bowel cancer over a ten-year period from 2006 to 2015.6 After adjustment for
patient specific factors (e.g. age, sex, ethnicity) and cancer specific factors (e.g. cancer site, grade, extent, time from
diagnosis, metastatic spread) survival was not significantly different between regions in New Zealand for people aged < 75
years, however, small regional differences were noted for people aged > 75 years.6
Both cancer-specific and all-cause survival was lower for Māori and Pacific peoples.6 Poorer outcomes for Māori
and Pacific peoples have been well documented previously, e.g. figures from the 2018 Piper report state a five-year risk
of death of 47% for Māori, 59% for Pacific peoples and 38% for Europeans.5 The factors likely to contribute to
these differences have also been well documented and include the higher proportion of metastatic disease at diagnosis, level
of deprivation, more co-morbidity and inequity in access to services and treatment received.5, 6
Overall patient outcomes after bowel cancer in New Zealand have, in the past, compared unfavourably with other countries,
e.g. Australia.6, 7 Although there has been some encouraging improvement in outcomes reported in these recent
papers, the authors caution that ongoing quality improvement should remain a priority.7
*Figures quoted include colon and rectal cancer but not anal cancer
†Most recent published data available
**Figures include anal cancer
The risk of disease recurrence after treatment for bowel cancer
As with most cancers, the risk of recurrence of bowel cancer is linked to the stage of the disease at diagnosis, and this
is also the strongest prognostic factor.5 People with stage I and IIa bowel cancer (see: “Staging bowel cancer”)
are at lower risk of recurrence than those who have been diagnosed with stage IIb or III, who are considered to be at high
risk of recurrence.8
A New Zealand study on disease recurrence in 237 patients after surgery for primary bowel cancer showed that:7
- There was an overall disease recurrence rate of approximately 25% five years after curative surgery. Approximate rates
of disease recurrence increased with the stage of the disease (see “Staging bowel cancer” for definitions):
- Stage I – 5%
- Stage II – 22%
- Stage III – 32%
- Stage IV – 60%
- The liver was the most common site of disease recurrence, followed by lung and local recurrence. Other less frequent
sites of recurrence included bone, brain, peritoneum, ovary and distant lymph nodes.
- Approximately 42% of recurrences were observed in the first year following surgery, increasing to nearly 73% within
the first two years. After this, annual recurrence rates decreased.
- Recurrence was detected by:
- CEA* testing 41%
- Routine imaging 32%
- Clinical symptoms and signs 27%
*Carcinoembryonic antigen test
Staging bowel cancer
Colon cancer staging:9, 10
- Stage 0 – Carcinoma in situ
- Stage I – Tumour is confined to the bowel wall
- Stage II – Tumour has spread through the bowel wall to the surrounding tissue or peritoneum
- Stage III – Tumour has spread to the regional lymph nodes
- Stage IV – Tumour is metastatic, i.e. spread to distant parts of the body, e.g. liver or lungs
Rectal cancer is staged in a similar way or may be staged more simply as non-metastatic (stage I – III) and metastatic (stage IV)
What follow-up is required and how often?
The aim of follow-up for people treated for bowel cancer is to enable recurrence to be detected at an early stage so that
additional curative treatment can be offered and outcomes improved.11
Current New Zealand surveillance guidance for people with a personal history of bowel cancer who have undergone
curative resection was published in 2012.12, 13 This guidance is under review by the National Bowel Cancer Working
Group (NBCWG) who have provided expert advice regarding the current situation in relation to the 2012 recommendations:
- Patients with a history of bowel cancer resection should be followed up under the direction of a multidisciplinary team.
This is likely to include primary care.
- Patients treated for bowel cancer should have a colonoscopy within 12 months of their initial surgery if the entire
colon was not assessed preoperatively
- Patients who have been treated surgically for bowel cancer who subsequently develop symptoms suggestive of recurrence
should be clinically assessed
Some specific components of follow-up differ for people who have had colon cancer from those who have had rectal cancer
(Table 1).12, 13
Other important aspects of follow-up include regular assessment of the patient’s psychological well-being and promotion
of healthy lifestyle factors to the patient and their whānau.14 Many patients experience altered bowel function
as a consequence of their treatment for bowel cancer and are likely to require information on dietary changes, stoma care,
bloating, excess flatus and managing diarrhoea, incontinence or constipation.14 Patients with severe symptoms
that do not respond to initial treatment with diet and stool modifying medicines may need referral back to their specialist
team.
The Cancer Society and Bowel Cancer New Zealand have several resources for patients on their websites,
including:
Table 1. Recommended follow-up for people treated for colon or rectal cancer. Adapted from New Zealand Guidelines Group with expert
advice from NBCWG.12, 13
N.B. Follow-up should be tailored to the individual patient, taking co-morbidities and cancer stage into consideration.
|
People with colon cancer (stages I – III) |
People with rectal cancer (stages I – III) |
| Physical examination |
Six monthly for the first two years then annually for three more years |
At three, six, 12 and 24 months and then annually for another three years |
| CEA* levels |
Six monthly for the first two years then annually for two more years |
Six monthly for the first two years then annually for two more years |
| Imaging, e.g. CXR, CT chest/ abdomen |
At least once between years one and three |
At least once between years one and three |
| DRE† and sigmoidoscopy |
N/A |
At six and 12 months then two years after initial surgery |
| Colonoscopy |
Initially one to three years after surgery then every three to five years depending on findings |
Initially DRE and sigmoidoscopy as above, then thereafter every three to five years |
*CEA: carcinoembryonic antigen
†DRE: digital rectal examination
Comparison to international guidance
Recent 2020 guidelines from the United Kingdom recommend that after bowel cancer treatment, a colonoscopy should be performed
within one year and following that a surveillance colonoscopy performed three years later.15 Further surveillance
is then determined by individual risk level, age and access to a national bowel screening programme.15
The National Institute for Health and Care Excellence (NICE) colorectal cancer guideline 2020 recommends follow-up for
three years after curative intent surgery to detect recurrence or metastases, including serum CEA and CT of the chest, abdomen
and pelvis.16
How long should patients be followed up?
Most people in New Zealand who have had bowel cancer will be followed up annually for five years.12
Data from New Zealand show that most disease recurrence (approximately 73%) occurs within two years following surgery.7 Patients
with rectal cancer, however, can experience delayed recurrence in the liver or lung after two to three years or more.11
People with a history of treated bowel cancer continue to be at a higher lifetime risk of disease recurrence and any return
of suggestive symptoms or signs should usually be investigated. Deciding when to stop regular follow-up should be a shared
decision between patient and clinician(s) and occur if it is thought that the risks of further investigations outweigh the
likely benefits, or when the patient can no longer tolerate further treatment.14
The role of carcinoembryonic antigen (CEA) testing
Carcinoembryonic antigen (CEA) is a tumour marker most often used, along with clinical review and other appropriate investigations,
to detect recurrence of bowel cancer.17 CEA is produced during fetal development, peaks and then declines with
age and is found in low levels in healthy adults. The presence of bowel cancer may increase CEA levels, however, it is non-specific
and levels can also be elevated in people with other malignancies including ovarian, gastric, pancreatic, lung and breast
cancer. In addition, CEA may be elevated in a number of non-cancerous conditions including inflammatory bowel disease, pancreatitis
and cirrhosis and in people who smoke.17 Very high CEA levels are usually associated with CEA-producing tumours
that are metastatic. However, tumour differentiation also influences CEA levels but in an inverse relationship; CEA is more
likely to be produced by a well-differentiated bowel cancer than a poorly-differentiated tumour.18
In general, the main application of CEA is for monitoring patients after surgical resection for bowel cancer to detect
recurrence. However, pre-operative and early post-operative CEA results do have prognostic significance; people with higher
pre-operative levels tend to have more advanced bowel cancer and if the level does not return to normal in the month following
surgical resection it is associated with poorer survival.17 Post-operatively a CEA level of > 5 micrograms/L
is associated with a higher rate of recurrence and cancer-related mortality.17 Levels that are > 10 micrograms/L
or that are trending upwards should prompt more urgent clinical review and investigations for recurrence.17
The recommendations for how frequently patients should have a CEA level requested post-operatively vary between international
guidelines. The testing frequency will normally be determined for an individual patient by their secondary care specialist
based on their specific clinical picture.
