Colorectal cancer

A guide for journalists on colorectal

cancer and its treatment
Contents Overview Section 1 Colorectal cancer Section 2 Epidemiology Section 3 Treatment References

Contents
Contents 2
Overview 3
Section 1: Colorectal cancer 4
i. What is colorectal cancer? 4
ii. Causes and risk factors 4
iii. Symptoms and diagnosis 5
iv. Staging 5
Section 2: Epidemiology 7
i. Incidence & mortality 7
ii. Prognosis 8
Section 3: Treatment 9
i. Surgery 9
ii. Chemotherapy 9
iii. Biological therapies 9
References 10

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Contents Overview Section 1 Colorectal cancer Section 2 Epidemiology Section 3 Treatment References

Overview
Colorectal cancer is one of the most common The standard treatments for colorectal
cancer are surgery, chemotherapy and
many patients are diagnosed at a later-
stage, when the cancer has already spread
cancers in the world, with over 1.2 million new biological therapies. Early-stage (localised) (metastasised) to other parts of the body.
cancer that has not spread (metastasised) At this point, the cancer is more difficult
cases diagnosed each year. Despite improvements in from the original site has the potential to treat and the prognosis for the patient
screening for early diagnosis, colorectal cancer remains to be cured if all the tumour cells can be is significantly worse.4 Awareness and
successfully removed by surgery. screening are therefore vital to improve the
one of the biggest cancer killers in the world and is prognosis for patients.5
However, the early signs and symptoms
responsible for over 600,000 deaths each year.1,2 of colorectal cancer are often ambiguous This guide provides an overview of
and can be confused with other diseases, colorectal cancer, including its incidence,
such as Irritable Bowel Syndrome, Crohn’s risk factors, symptoms, diagnosis and
disease or peptic ulcers.3 This means that treatment options.

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 Contents Overview Section 1 Colorectal cancer Section 2 Epidemiology Section 3 Treatment References

Section 1
Colorectal cancer
i. What is colorectal Figure 1 Origins of colorectal cancer
cancer?
Colorectal cancer
Colorectal cancer is caused by the abnormal begins as a small clump
growth of epithelial cells which form the of cells that grow in Stomach
lining of the colon or rectum. These small the intestinal wall
growths (known as polyps) are often benign, Colon
although some have the potential to develop
and become cancerous. It is estimated that Cancer cells
up to two thirds of colorectal polyps are Small intestine
pre-malignant and associated with a risk of
colorectal cancer.6
Appendix

Screening and awareness can reduce Rectum

mortality of colorectal cancer by detecting
and removing polyps before they become
Risk factors: • Colorectal polyps or inflammatory cancer. Studies have also linked obesity,
cancerous, or by discovering the cancer at an
• Family history: A person’s risk doubles bowel diseases: A history of polyps lack of exercise, smoking and excessive
earlier stage, where treatment has a higher
if a direct relative has previously had or inflammatory bowel disease, where alcohol consumption to a greater risk of
success rate.5 However, there are often no
the disease. There is an even greater the bowel is inflamed for many years, colorectal cancer.7
initial symptoms and the cancer may already
risk if more than one relative has had increases the risk of colorectal cancer.7 Potential protective agents:
have spread to other parts of the body by the
colorectal cancer.2 • Age: Although a person can develop • Non-steroidal anti-inflammatory
time the patient is diagnosed.
• Genetics: Individuals with inherited colorectal cancer at any age, the risk drugs (NSAIDs), such as aspirin, have
disorders such as familial adenomatous increases greatly with age. Over 90% been associated with a reduced risk
ii. Causes and risk factors
polyposis (FAP), where an individual is of colorectal cases are diagnosed in of colorectal cancer. A healthy, fibre-
There are several risk factors that may
prone to polyp formation, have a patients over the age of 50.7 containing diet and hormone replacement
increase the chance of an individual
higher risk of developing colorectal • Lifestyle: A sedentary lifestyle is therapy in women are also possible
developing colorectal cancer.
cancer.2 associated with a higher risk of colorectal protective factors.8,9

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 Contents Overview Section 1 Colorectal cancer Section 2 Epidemiology Section 3 Treatment References

iii. Symptoms and diagnosis high-risk symptoms to their doctor they iv. Staging the tumour has metastasised to distant
will be given a physical examination. If this Staging determines how advanced the organs in the body, most commonly the
Early diagnosis of colorectal cancer has the
raises any concerns, a number of additional cancer is and whether it has spread to liver or lungs. T, N and M are followed by
potential to improve survival rates; however
tests may be performed:12 other parts of the body. It helps to identify numbers giving further information on the
early symptoms (such as abdominal pain)
the most appropriate treatment options for stage of the disease: increasing numbers
may be confused with other diseases,3
• Colonoscopy – the entire length of the the patient. Staging in colorectal cancer signify later stages.16
meaning many patients have advanced
colon is viewed using a colonoscope. can be confirmed by:13
disease when diagnosed.4 Almost 85% of
• Sigmoidoscopy – a small tube
patients referred to hospital have one or Table 1 The stages of colorectal cancer (TNM)13,14
(sigmoidoscope) is used to view the • Blood tests to look for tumour markers
more of the following high-risk symptoms:10
lower colon. • Biopsies, analysing tissue samples taken Stage Classification
• Rectal bleeding • Double contrast barium enema – x-rays during a colonoscopy or sigmoidoscopy Stage I The tumour is localised to
• A mass in the abdomen or rectum of the colon and rectum. Barium lines • Imaging tests (CT scans, chest x-rays, the lining of the colon.
• Change in bowel habit the colon allowing an outline to be ultrasound, MRI scans) T1-T2, N0, M0
• Perianal symptoms, such as abscesses viewed in an x-ray.12 • Surgery Stage II The tumour grows into the
or lesions outer lining of the colon or
The most common staging for colorectal surrounding tissue.
A biopsy, where sample tissue is removed
cancer is defined by the tumour, node, T3-T4, N0, M0
As the cancer becomes more advanced, during a colonoscopy or sigmoidoscopy,
metastasis (TNM) staging system, which
other symptoms can develop. For example, is required to confirm the diagnosis of Stage III The cancer has metastasised
classes a patient into stages I-IV according to the lymph nodes.
excessive bleeding from the colon can colorectal cancer and determine how
to the level of invasion or spread of the Any T, N1-N2, M0
cause anaemia, which leaves the patient advanced the disease is (staging).12
tumour to other organs (metastasis).14,15
feeling breathless and tired. If the cancer Stage IV The cancer has metastasised
begins to obstruct the colon, further Using the TNM staging, the progression of to distant organs in the body.
symptoms include bloating, constipation Any T, Any N, M1
the original primary tumour is denoted by
and vomiting.11 the letter T (tumour); N (node) indicates
whether the tumour has spread to lymph
Methods of diagnosis vary from country to nodes; M (metastasis) represents whether
country but typically if a patient presents

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 Contents Overview Section 1 Colorectal cancer Section 2 Epidemiology Section 3 Treatment References

‘Early-stage’ disease (stage I and II)

Figure 2 Stages of colorectal cancer
describes a tumour that has not yet spread
to the lymph nodes or other distant areas
in the body. With early-stage disease there Blood vessels
Colon
is the chance of cure if the tumour can Lymph nodes Cancer spreads to other
be successfully surgically removed. When parts of the body

cancer spreads from the original site,

affecting the lymph nodes (stage III) or
other parts of the body (stage IV),
treatment becomes more difficult.

Stage IV

Stage 0
Stage III
Stage I Stage II

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 Contents Overview Section 1 Colorectal cancer Section 2 Epidemiology Section 3 Treatment References

Section 2
Epidemiology
i. Incidence & mortality 609,000 deaths each year (8% of all cancer year;1 the highest incidence rate of in North America in 2008, making it the
deaths),1 making it the fourth leading cause colorectal cancer in the world. It is also the second most commonly diagnosed cancer
Worldwide
of cancer death after lung, stomach and second greatest cause of cancer death in in the region. Colorectal cancer accounted
Colorectal cancer is diagnosed in over 1.2
liver cancers. Europe following lung cancer, accounting for 11% of all cancer incidence and 9% of
million people globally each year; it is the
Europe Colorectal cancer is the for 12% of all cancer deaths. all cancer deaths in North America in the
second most common cancer in women
most common cancer in Europe, with North America There were approximately same year.1
and the third most common cancer in men.
The disease is responsible for approximately approximately 430,000 new cases each 177,000 new cases of colorectal cancer

Figure 3 Colorectal deaths by region, as a percentage of the incidence of all cancers Figure 4 Incidence and mortality of some of the most common cancers worldwide

1.2 million
new cases each year

Breast
1,384,155
458,503

Prostate
899,102
258,133

Lung
1,092,056
948,993
515,999
427,586
Incidence and mortality of
12.8% of all
some of the most common
cancer deaths in
Colorectal cancers worldwide
Australia & New Zealand 663,904 571,204
320,397 288,654
5.3% of all
cancer deaths Stomach
in Africa
640,031 348,571 Male incidence Female incidence
4th leading cause 463,930 273,489
Male mortality mortality
of cancer death globally Liver
523,432 226,312
12.8% of all 478,134 217,592
8%
Source WHO IARC GLOBOCAN, Cancer incidence and Mortality Worldwide in 2008 at http://globocan.iarc.fr/
Responsible for cancer deaths in
of all cancer deaths Australia & New Zealand

Source WHO IARC GLOBOCAN, Cancer incidence and Mortality Worldwide in 2008 at http://globocan.iarc.fr/

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 Contents Overview Section 1 Colorectal cancer Section 2 Epidemiology Section 3 Treatment References

ii. Prognosis Figure 5 Incidence and mortality of some of the most common cancers worldwide
Cancer statistics often use an ‘overall
Colorectal cancer average 5-year survival rate depending on stage of diagnosis
5-year survival rate’ to give a better idea of
the longer term outlook for people with a
particular cancer. The overall 5-year survival
rate for colorectal cancer patients is 65%,17
although this differs greatly depending on
how advanced the cancer is.

The 5-year survival rate for a patient

diagnosed with stage I or II colorectal
cancer, where the tumour is localised to 5-year survival rates for 5-year survival rates for
early-stage CRC: up to 90% later-stage CRC: 12%
the colon, is up to 90%. Approximately
Survivors Fatalities
two fifths of patients are diagnosed at this Source Altekruse SF et al. SEER Cancer Statistics Review, 1975-2007, National Cancer Institute. http://seer.cancer.gov/csr/1975_2007/

stage. However the 5-year survival rate for

patients diagnosed with stage IV disease,
once the cancer has metastasised to other
organs, is only 12%.17

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 Contents Overview Section 1 Colorectal cancer Section 2 Epidemiology Section 3 Treatment References

Section 3
Treatment
Treatment options for patients vary and are i. Surgery ii. Chemotherapy unfortunately, in the majority of cases
assessed taking into account the following the disease eventually progresses after
The majority of patients with early-stage Patients diagnosed with advanced disease
variables: first-line treatment. When this occurs
colorectal cancer will undergo surgery to are usually treated with chemotherapy
the patient may undergo another round
remove as much of the tumour as possible after surgery, known as ‘first-line’
• Tumour size of chemotherapy, known as ‘second-line’
in a procedure known as ‘resection’. Any treatment. This involves a combination of a
• Stage of diagnosis treatment. Detecting disease recurrence
areas surrounding the cancerous tissue fluoropyrimidine and most often fluorouracil
• The location of the tumour in the colon early is important in improving survival as
and nearby lymph nodes will also be (5-FU) with leucovorin (folinic acid or LV)
or rectum unfortunately 30%-50% of patients will
removed to reduce the risk of the cancer and oxaliplatin, known as FOLFOX19 or with
• The risk of the cancer returning eventually die from the disease, so patients
spreading. Resection is also a treatment irinotecan, known as FOLFIRI.
• The physical health of the patient are routinely checked after completing the
option for some patients with later stage
chemotherapy regimen.19,21
In general the current treatment options disease, particularly when the cancer has Some patients with advanced colorectal
for colorectal cancer are surgery, metastasised to the liver. A less invasive cancer who are not initially able to undergo
chemotherapy, and biological therapies. procedure known as laparoscopic resection, surgery due to invasive tumours can be iii. Biological therapies
Radiotherapy is not often used to treat where the affected area of the colon is treated with chemotherapy before being Several types of biological therapy are
metastatic colorectal cancer due to side- removed through keyhole surgery, can also considered for surgery (called neoadjuvant available to treat metastatic colorectal
effects, although it can be used after be performed on patients with early-stage treatment).20 cancer including anti-angiogenics and the
surgery to destroy any residual colorectal cancer.19 Epidermal Growth Factor Receptor (EGFR)
cancer cells.18 Many people with colorectal cancer inhibitors. Biological therapies are typically
initially respond to chemotherapy, but given in combination with chemotherapy.

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 Contents Overview Section 1 Colorectal cancer Section 2 Epidemiology Section 3 Treatment References

References
1 
WHO, IARC GLOBOCAN, Cancer Incidence and Mortality Worldwide in 2008 at 16 
American Cancer Society Colorectal Cancer Guide: How is colorectal cancer staged? Last accessed
http://globocan.iarc.fr/ April 2011 at http://www.cancer.org/cancer/colonandrectumcancer/detailedguide/colorectal-cancer-
staged
2 
Edwards BK et al. Annual Report to the Nation on the Status of Cancer, 1975-2006, Featuring
Colorectal Cancer Trends and Impact of Interventions (Risk Factors, Screening, and Treatment) to Altekruse SF et al. SEER Cancer Statistics Review, 1975-2007, National Cancer Institute. http://seer.
17 
Reduce Future Rates. Cancer (2009) 116(3):544-573 cancer.gov/csr/1975_2007/
3 
John SKP, George S, Primrose JN and Fozard JBJ (2011), Symptoms and signs in patients with 18 
American Cancer Society Colorectal Cancer Guide: Treating Colon/Rectum Cancer. Last accessed
colorectal cancer. Colorectal Disease, 13: 17–25 April 2011 at http://www.cancer.org/cancer/colonandrectumcancer/detailedguide/colorectal-cancer-
treating-radiation-therapy
4 
Henley SJ et al. MMWR Surveill Summ. 2010 59(9):1-25
19 
Labianca R et al. Annals of Oncology 21 (Supplement 5): v70–v77, 2010
5 
Garcia M et al. Global Cancer Facts & Figures. Atlanta, GA: American Cancer Society, 2007.
20 
Hennessy B et al. Lancet 2009; 9698: 1371-1382
6 
Levin B et al. Gastroenterology 2008; 134 (5): 1570-1595
21 
National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Colon
7 
American Cancer Society, Risk Factors for Colorectal Cancer. Last accessed March
Cancer. V.2.2011
2011 at http://www.cancer.org/Cancer/ColonandRectumCancer/MoreInformation/
ColonandRectumCancerEarlyDetection/colorectal-cancer-early-detection-risk-factors-for-c-r-c
8 
Boyle P, Leon ME, Epidemiology of colorectal cancer. British Medical Bulletin (2002) 64:1–25
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9 
colon_cancer/page2.htm#3whatare
10 
Flashman K, O’Leary DP, Senapati A, Thompson MR. Gut 2004; 53: 387–91
NHS UK bowel cancer symptoms. Last accessed April 2011 at: http://www.nhs.uk/Conditions/
11 
Cancer-of-the-colon-rectum-or-bowel/Pages/Symptoms.aspx
12 
eMedicine, Colon Adenocarcinoma: Differential Diagnoses & Workup. Last accessed March 2011 at
http://emedicine.medscape.com/article/277496-overview
13 
Saunders TH et al. Br Med Bull (2002) 64(1): 81-99
14 
AJCC: Colon and rectum. In: Edge SB et al. eds.: AJCC Cancer Staging Manual. 7th ed. New York,
NY: Springer, 2010, pp 143-164
15 
Frederick LG et al. CA Cancer J Clin 2008; 58:180-190

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