Colorectal Cancer Flashcards
What is another term for colorectal cancer?
Bowel cancer
What is colorectal cancer?
It is defined as a malignancy affecting the colon and rectum
How common is colorectal cancer?
It is the third most common cancer in the UK
It is the second most common cause of cancer deaths
What are the three main classifications of colorectal cancer?
Right Sided Colon Cancer
Left Sided Colon Cancer
Rectal Lesions
Is right sided colon cancer exophytic or annular? What does this mean?
Exophytic
This means that these lesions grow outwards beyond the surface epithelium from which it originates
What are the three clinical features of right sided colon cancer?
Abdominal Pain
Iron Deficiency Anaemia
Bowel Habit Changes, Diarrhoea > 6 Weeks
Is left sided colon cancer exophytic or annular? What does this mean?
Annular
This means that these lesions form around the lumen of the colon
What are the three clinical features of left sided colon cancer?
Abdominal Pain
Rectal Bleeding
Bowel Habit Changes, Diarrhoea > 6 Weeks
What are the three clinical features of rectal cancer?
Tenesmus
Fresh Rectal Bleeding
Incomplete Bowel Evacuation
What percentage of colorectal cancers are located in the rectum?
40%
What percentage of colorectal cancers are located in the sigmoid colon?
30%
What percentage of colorectal cancers are located in the descending colon?
5%
What percentage of colorectal cancers are located in the transverse colon?
10%
What percentage of colorectal cancers are located in the ascending colon and caecum?
15%
What are the seven risk factors of colorectal cancer?
Increased Age, 85 – 89 Years Old
Male Gender
Familial Adenomatous Polyposis (FAP)
Hereditary Non-Polyposis Colorectal Cancer (HNPCC)
Peutz-Jeghers Syndrome
Inflammatory Bowel Disease
Obesity
What is FAP?
It is a genetic condition in which individuals develop adenomatous polyps by the time they are 30-40 years old
What is the inheritance of FAP?
Autosomal dominant
What genetic mutation results in FAP? What chromosome is this gene located on?
A mutation affecting the tumour suppressor gene called adenomatous polyposis coli gene (APC)
Chromosome 5
How do we diagnose FAP?
We conduct genetic testing by analysing DNA from WBC’s
How do we manage FAP?
In their 20s, patients have a total colectomy with ileo-anal pouch formation
What is the most common inherited colorectal cancer?
HNPCC
What is another term for HNPCC?
Lynch syndrome
What is HNPCC?
It is a genetic condition in which a mismatch repair defect promotes the development of adenoma
The progression of adenoma to carcinoma is accelerated in these patients
What is the inheritance of HNPCC?
Autosomal dominant
What two genes are associated with HNPCC colorectal cancer?
MSH2
MLH1
What other seven cancers are HNPCC patients at risk of?
Gastric cancer
Small bowel cancer
Urothelial cancer
Prostate cancer
Pancreatic cancer
Endometrial cancer
Ovarian cancer
What is the second most common cancer associated with HNPCC > colorectal cancer?
Endometrial cancer
What criteria is used to help identify the risk of HNPCC related cancers?
Amsterdam criteria
What are the four components of the Amsterdam criteria?
- At least 3 family members with Lynch syndrome
- One affected family member is a first degree relative
- The cases span at least two successive generations
- At least one cancer case diagnosed before the age of 50 years
What is Peutz-Jeghers syndrome?
It is a genetic condition resulting in the development of hamartomatous polyps
What is the inheritance of Peutz-Jeghers syndrome?
Autosomal dominant
What are the four clincial features of Peutz-Jeghers syndrome?
Hamatomatous Small Bowel Polyps
Small Bowel Obstruction
Gastrointestinal Bleeding
Pigmented Oral/Palm/Sole Lesions
How does IBD increase the risk of colorectal cancer?
This is due to the fact that this condition destroys the mucosa, which means the cells are being renewed more frequently compared to a none affected individual
This increases the chances of defects occurring
What are the eight clinical features of colorectal cancer?
Rectal Bleeding > 6 Weeks
Bowel Habit Changes, Diarrhoea > 6 Weeks
Abdominal Mass
Abdominal Pain
Abdominal Distension
Tenesmus
Weight Loss
Iron Deficiency Anaemia
What can the colour of rectal bleeding indicate?
The location of the colon cancer
What does black rectal blood indicate?
The cancer is present in the colon
What does fresh red rectal blood indicate?
The cancer is present in the rectum
What is tenesmus?
It refers to a patient feeling they need to have bowel movement, even if they’ve already had one
Why is unexplained iron deficiency anaemia a clinical feature of colon cancer?
This clinical feature is due to blood loss from rectal bleeding
How soon should patients recieve an appointment with colorectal services following urgent referral?
2 weeks
What two clinical features in > 40 year old patients requires an urgent referral to colorectal services?
Unexplained weight loss
AND
Abdominal pain
What clinical feature in > 50 year old patients requires an urgent referral to colorectal services?
Unexplained rectal bleeding
What two clinical features in > 60 year old patients requires an urgent referral to colorectal services?
Iron deficiency anaemia
OR
Change in bowel habit
In which three circumstances should an urgent referral be considered for investigation of colorectal cancer?
In cases where there is a rectal or abdominal mass
In cases where there is an unexplained anal mass or anal ulceration
In cases where patients are < 50 years old with rectal bleeding AND any one of the following unexplained symptoms: abdominal pain, bowel habit change, weight loss and iron deficiency anaemia
What are the four investigations used to diagnose colorectal cancer?
Blood tests
Colonoscopy
CT Colongram
Barium Enema
What three blood test results indicate a diagnosis of colorectal cancer?
Decreased Haemoglobin Levels
Increased Platelet Levels
Carcinoembryonic Antigen (CEA) Levels
What is CEA?
It is the main tumour marker in colorectal cancer
How are CEA levels used to investigate colorectal cancer?
It is not a diagnostic investigation due to the fact that it can be elevated in other conditions, such as IBD
It is however a marker for colorectal cancer once the diagnosis is made
What is the gold standard investigation when diagnosing colorectal cancer?
Colonoscopy
What is a colonoscopy?
It involves the placement of an endoscope into the colon
In what three ways is a colonoscopy used to diagnose colorectal cancer?
It is used to provide visualisation of the mucosa
A colon biopsy can be taken for histological confirmation
It can be used to remove any polyps
What three drugs do we administer to patients prior to the conduction of a colonoscopy?
Laxatives
Analgesia
Sedatives
When should individuals take laxatives in order to prepare for colonoscopy?
They should take them the day before the procedure
What is a CT colonogram?
It is an imaging scan that produces a cross sectional image of the colon and rectum
When do we select a CT colongram as the first line investigation for diagnosing colorectal cancer? Why?
Patients > 80 years old
No bowel preparation is needed
What is a barium enema?
It involves the administration of barium contrast via the rectum to visualise the colon better on x-ray
What is the sign of colorectal cancer on barium enema?
The apple core sign, which is constriction of the colon lumen
What two staging systems are used to stage colorectal cancer?
TNM
Duke’s
What two imaging scans are used to stage colorectal cancer?
CT chest abdomen and pelvis
CT colonograms
Define Duke’s Stage A
Confined To The Muscularis Mucosa
Define Duke’s Stage B
Extends Through The Muscularis Mucosa
Define Duke’s Stage C
Lymph Node Involvement
Define Duke’s Stage D
Distant Metastasis
In which individuals do we conduct standard colorectal cancer screening in? How often do we conduct screening in these individuals?
50-74 years old
Every 2 years
What screening investigation is used in colorectal cancer?
Faecal immunochemical test (FIT)
What is FIT?
It involves checking stool samples for the presence of microscopic blood
It uses antibodies that specifically recognise human haemoglobin
What FIT result indicates further investigation? What is the next screening investigation used?
80mg/ml of blood in stool
Colonoscopy
What screening test was used before FIT? Why is FIT favourable?
Faecal Occult Blood Test (FOBT)
FIT is more specific for haemoglobin and it is therefore a more reliable investigation
Which five high risk patient groups also undergo colorectal cancer screening?
FAP
HNPCC
IBD
Previous Colorectal Cancer
Family History
What colorectal cancer screening is offerred to FAP patients?
A colonoscopy annually > 12 years old
What colorectal cancer screening is offerred to HNPCC patients?
A colonoscopy every 6 months > 25 years old
What colorectal cancer screening is offerred to IBD patients?
A colonoscopy 10 years > diagnosis
What colorectal cancer screening is offerred to previous colorectal cancer patients?
A colonoscopy one year > surgery
THEN
A colonoscopy every three years
When is surgical management of colorectal cancer recommended?
It is the first line management option
What are the six surgical procedures used to treat colorectal cancer?
Right Hemicolectomy
Left Hemicolectomy
High Anterior Resection
Hartmann’s Procedure
Anterior Resection
Abdomino-Perineal Excision of Rectum (APER)
When is a right hemicolectomy used to manage colorectal cancer?
It is used to manage colorectal cancer affecting the caecal, ascending or proximal transverse colon
What is a right hemicolectomy?
It involves removing the right side of the colon – including the caecum, ascending colon, hepatic flexure, first third of the transverse colon and part of the terminal ileum, along with fat and lymph nodes
How is bowel function restored following a right hemicolectomy?
Ileo-colic anastomosis
When is a left hemicolectomy used to manage colorectal cancer?
It is used to manage colorectal cancer affecting the distal transverse and descending colon
What is a left hemicolectomy?
It involves removing the left side of the colon – including the transverse colon to the level of the upper rectum
How is bowel function restored following a left hemicolectomy?
Colo-colon anastomosis
When is a high anterior resection used to manage colorectal cancer?
It is used to manage colorectal cancer affecting the sigmoid colon
What is a high anterior resection?
It involves removing the sigmoid colon and the upper section of the rectum
How is bowel function restored after a high anterior resection?
Colo-rectal anastomosis
When is an anterior resection used to manage colorectal cancer?
It is used to manage colorectal cancer affecting the rectum
What is an anterior resection?
It involves removing the upper/mid section of the rectum and the mesorectal fat and lymph nodes
How is bowel function restored after an anterior resection?
Colo-rectal anastomosis
When is a Hartmann’s procedure recommended?
It is recommended to treat sigmoid colorectal cancers which are perforated or obstructive
They are therefore demmed as unsafe for a primary anastomosis due to the high risk of anastomotic leak
What are three clinical features of bowel performation?
Abdominal Pain
Peritonism
Fever
What is a Hartmann’s procedure?
It involves complete resection of the rectum and sigmoid colon with the formation of an end colostomy and the closure of the rectal stump
This can be revised later, with anastomosis of the two stumps
When is an abdomino-perineal excision of the rectum (APER) used to manage colorectal cancer?
It is used to manage colorectal cancer affecting the anal verge – typically those close to the sphincter complex or very low rectal cancers
What is APER?
It involves removing the distal colon, rectum and anal sphincter
How is bowel function restored following an APER?
A permanent stoma bag
What is an important factor to establish prior to the undertaking of colorectal cancer surgery?
Whether an attempt will be made to restore intestinal continuity, via anastomosis of bowel ends, or whether stoma formation is favourable
What is a stoma?
An opening in the abdomen that is connected to the gastrointestinal system
A colostomy bag is then placed over this opening to collect waste products that would normally pass through the rectum and anus
When is a temporary stoma recommended to manage colorectal cancer?
In emergency settings, where the bowel has perforated
What are the two types of stomas?
Ileostomy
Colostomy
In which location do we place an ileostomy? What type of stools are removed from these stoma bags? How do these stomas looks?
Right Iliac Fossa
Liquid, Looser Stools
Spouted
In which location do we place an colostomy? What type of stools are removed from these stoma bags? How do these stomas looks?
Left Iliac Fossa
Solid Stools
No Spout, Flush With Skin
Following colorectal cancer surgery, which form of analgesia is recommended? Why?
Epidural
It enables a faster return of normal bowel function
What are two post-operative complications following colorectal cancer surgery?
Post-Operative Ileus
Anastomotic Leak
What are the four clinical features of ileus?
Abdominal Pain
Abdominal Bloating
Nausea & Vomiting
Absent Bowel Sounds
What investigation is used to screen for anastamostic leak following colorectal cancer surgery?
Gastrografin Enema
What are the two management options of post-operative ileus?
Insert NG Tube
Nil by Mouth
What are the six clinical features of an anastomotic leak?
Fever
Abdomen Distension
Absent Bowel Sounds
Feculent Material In Wound Drain
Atrial Fibrillation
Hypertension
What feeding option should be selected following colorectal cancer surgery?
Normal Oral Intake
In which two circumstances do we use chemotherapy to manage colorectal cancer?
In individuals who are unfit for surgical management
It can be used as a neoadjuvant or adjuvant with surgical management in those with a high risk of reoccurrence
When is neoadjuvant radiotherapy used to manage colorectal cancer? Why?
Rectal cancer T3, T4
This is due to the fact that it is an extraperitoneal structure and therefore it is possibile to irradiate it
Which screening investigation is used to monitor individuals with colorectal cancer?
CEA levels
