Colorectal Cancer Flashcards
What is irritable bowel syndrome (IBS)?
A chronic illness characterised by abdominal pain/discomfort and disturbed bowel habit in the absence of causative disease.
Which gender is more prevalent for irritable bowel syndrome?
Women
What criteria is used to diagnose IBS?
The Rome Criteria
According to the Rome Criteria, how many weeks of abdominal discomfort or pain are required for IBS diagnosis?
12 weeks
What are the three key features associated with the abdominal discomfort or pain in IBS in the Rome criteria?
- Relief by defaecation
- Associated with change in stool frequency
- Associated with change in stool appearance
What are some supporting clinical features of IBS?
- Long history with relapse and remitting course
- Exacerbations triggered by life events
- Co-morbidity of anxiety/depression
- Symptoms worsened by eating
What symptoms support the diagnosis of IBS?
- Bloating
- Abdominal distention
- Passing mucus
- Abnormal stool frequency
- Abnormal stool form
What is the pathophysiology of IBS?
Increased contractility of intestinal muscles with increased sensitivity to visceral stimulation and underlying inflammation linked to stress, with triggers including post culture-positive gastroenteritis being a strong risk factor. There may be presence of food intoelerance and skin atopy and triggers for sensitisation.
Gut mucosa in IBS shows chronic inflammatory cells mas cells and IBS-D (diarrhoea) will have more mucosal T lymphocytes than IBS-C.
What are some strong risk factors for IBS?
- Post culture-positive gastroenteritis
- Food intolerance
- Skin atopy
What is a notable difference in the gut mucosa between IBS-D and IBS-C?
IBS-D will have more mucosal T lymphocytes than IBS-C.
What are alarm features of IBS?
- Onset after age 50
- Progressive deterioration
- Weight loss
- Fever
- Rectal bleeding
- Steatorrhoea
- Dehydration
- Family history of organic gastrointestinal disease
What routine diagnostic testing is not recommended for IBS?
In the absence of alarm findings like iron deficiency anaemia, weight loss, and haematochezia.
What tests are included in the investigations for IBS?
- FBC with metabolic panel
- Inflammatory markers
- Thyroid levels
- Stool culture for C-diff, giardiasis, cryptosporidium, and faecal leukocytes
- Testing for coeliac with tissue transglutaminase antibody
- Colonoscopy
What is the primary focus of IBS treatment?
Resolving pain, bloating, cramping and diarrhoea or constipation.
Laxative
Anti-spasmodic agents
Anti-diarrhoea agents
Anti-depressants
FODMAPS
What type of laxatives should be used for treating constipation in IBS?
Non-stimulant osmotic laxatives like macrogol.
What are examples of anti-spasmodics used in IBS treatment?
- Mebeverine
- Hyoscine
- Butylbromide
What anti-diarrhea agent is commonly used for IBS?
Loperamide
Which types of antidepressants may be used in IBS treatment?
- Tricyclics
- SSRIs
What dietary components are known as FODMAPs?
- Wheat
- Fruits
- Vegetables
Fermentable short chain Fatty acids which can contribute to the symptoms of IBS
What medication may be used to treat IBS and reduce abdominal pain and diarrhoea?
Rifaximin
True or False: There is a strong association of IBS with anxiety and depression.
True
What is a key criterion for referral in colorectal cancer for patients over 60 years old?
Change in bowel habit over 6 weeks.
Rectal bleeding over six weeks in over 50 year olds
* Rectal bleeding with change of bowel habit becoming looser in over 60s
* Palpable right lower abdominal or rectal mass
* Over 60 year olds with Iron deficiency anaemia
* Positive faecal immunochemcial test
What are the investigations for colorectal cancer?
Full colonoscopies evaluation is essential and the gold standard and enable biopsy and removal of polyps to reduce the risk of spread.
Barium enema: x ray with orally ingested contrast
CT scan of chest, abdomen and pelvis to identify metastases
CT colography
FBC for Hb, MCV and colonic embryonic antigen, a tumour marker for colorectal cancer.
What can be used as an indicator for severity of colorectal cancer?
Carcinoembroynic antigen should not be used as a diagnostic test due to poor sensitivity and specificity but can be used to monitor disease progression and treatment efficacy. Elevated baseline CEA is assoicated with worse prognosis
What is a key symptom indicating colorectal cancer in patients over 50?
Rectal bleeding over six weeks.
What does a palpable right lower abdominal or rectal mass indicate?
Possible colorectal cancer.
What is the gold standard for evaluating colorectal cancer?
Full colonoscopy.
What imaging technique involves orally ingested contrast for colorectal evaluation?
Barium enema.
What is the purpose of carcinoembryonic antigen (CEA) in colorectal cancer?
Monitor disease progression and treatment efficacy.
True or False: Carcinoembryonic antigen is recommended as a diagnostic test for colorectal cancer.
False.
What is the typical screening age range for colon cancer?
Adults aged 60-75 years old, every 2 years with a faecal immunochemistry test.
What is the colonoscopy schedule for IBD patients?
For patients with IBD, surveillance colonoscopy will occur 8-10 years post disease onset and then surveillance every three years for the next decade
What are the clinical signs of colorectal cancer?
Right sided colon cancer will produce a firm palpable mass in right iliac fossa. They tend to be at a worse stage of prognosis because disease advances longer due to wider side of colon before causing obstruction.
Rectal cancer will have a rolled edge
What is a preventive measure for colorectal cancer?
Aspirin use and NSAIDs which inhibit tumour development. High fibre diet and lower calorie intake
What staging system has replaced the Dukes system for colorectal cancer?
TNM system.
What does Tis represent in the TNM staging system?
Carcinoma in situ.
What is T1?
into submucosa
What is T2?
into muscularis propia
What is T3?
Through muscularis propia into subserosa
What is T4a?
peneates visceral perioneum
What is T4b?
penerates to adjacent organs
What is a right hemicoloectomy?
for ascending colon tumours or transverse colon tumours, with removal of the right colic and ileocolic branches of the superior mesenteric artery. Extended right hemicoloectomy may involve removal of the transverse colon.
When is right hemicolectomy performed other than bowel malignancy?
Apart from bowel malignancy, they may be performed for diverticular disease, bowel ischaemia or perforation. This is more common than left hemicoletomy
What is left hemicolectomy?
Left hemicoectomy is ideal for descending colon tumours, with removal of the left branch of the middle colic vessels, inferior mesenteric vein and left colic vessels from inferior mesenteric artery and inferior mesenteric vein.
What is an alternative to bowel malignancy for left hemicolectomy?
An anastomosis is formed from the transverse colon to the sigmoid colon. It is typically performed for cancer but an be performed for Diverticular disease, bowel perforation or bowel ischaemia
What is the management for early colorectal cancer (T1-T2, N0, M0)?
Local tumor resection and adjuvant chemotherapy.
What is the treatment of stage 3 colorectal cancer?
Short-course radiotherapy and
capecitabine with oxaliplatin for 3 months:
* Second line is oxaliplatin with 5-fluorouracil and foil IC acid
* Single agent fluoropyrmidine for 6 months
-> oxaliplatin is an alkylating agent which causes cross linking
-> capecitabine inhibit DNA synthesis by reducing thymidine production
-> fluoropyrimidine inhibits thymidylte synthase
What is the treatment for advanced disease?
chemotherapy
When is radiotherapy used in colorectal cancer?
radiotherapy is reserved for rectal cancer due to the risk of damage to the small bowel. In rectal cancer, radiotherapy is used before treatment along with chemotherapy
What surgical procedure is ideal for high rectal tumors over 5cm from anus?
Anterior resection to leave the anal sphincter intact?
what is Hartmann’s procedure?
Hartmann’s procedure is used in emergency bowel surgery, such as bowel obstruction or perforation wit complete resection of the recto-sigmoid colon with the formation of an end colostomy and closure of rectal stump. Bowel obstruction can also be treated with a decompressing colostomy (stoma) or endoscopic stunting.
What is the indication for Hartmann’s procedure?
Emergency bowel surgery.
What is the primary treatment for advanced colorectal cancer?
Chemotherapy.
What chemotherapy agent is an alkylating agent causing cross-linking?
Oxaliplatin.
Fill in the blank: Colonic stents can be used for _______.
Bowel obstruction.
What is the most common site of metastasis from colorectal cancer?
Liver.
What does surgical management of cancer?
Surgical management of the cancer is removing the tumour and the vessels supplying it and the lymphatics and resection of any structures atttached to the tumour, with a 5cm margin of bowel on either side of the tumour to mini site he possibility of an anastomotic reccurence
Where do rectal cancers commonly invade?
the uterus, vagina, bladder
What is laparoscopic surgery?
Laparoscopic surgery is a minimally invasive surgery through the abdomen with small incisions using a camera to assess the contents like the reproductive organs and bowel and bladder. laparoscopic colostomy creates an incision in the bowel to create an opening for faeces to enter a bag.
What is the purpose of a surgical drain?
Remove pus, blood, or fluids from a body cavity.
What is a colectomy?
Removal of the entire bowel.
What is a colostomy?
stoma from colon.
What is proctocoelctomy?
Large bowel and rectum removed. Therefore the ileum and rectum must be joined together which involves creating a J pouch. A J pouch is an ideal pouch that acts as a replacement for the rectum and is connected to the anus using a surgical stapler. To allow the pouch to heal, a temporary osteomyelitis bag will be made and kept for 2-3 months. Stools will be looser and more liquid due to the absence of the colon.
What is an ileostomy?
Opening from the ileum.
What is anterior resection?
Anterior resection is an operation to remove the rectum and sigmoid colon, for sigmoid or rectal cancer. It is classified into standard/high resection or low resection or ultra-low anterior resection.
What is high resection?
High resection is removal of the sigmoid colon and the upper region of the rectum. The remaining descending colon is joined to the remaining rectum as an anastomosis, with the use of a circular stapler device.lymph nodes in the region are also removed. It is unlikely that a stoma will be needed, but if necessary, a temporary stoma called ileostomy will be made.
What is low anterior resection syndrome?
Characterized by fecal incontinence, tenesmus, diarrhea. Low anterior resection is used to remove some or all of the sigmoid colon and part of the lower region of the rectum, typically via laparoscopic surgery and an anastomosis is made. Preparations include a low-fibre diet. There is a higher risk of anastomic leak, so a de functioning ileostomy is often used.
What is ultra-low resection?
Ultra-low resection involves removing sigmoid Colon and all or up to the lower portion of the rectum, along with nearby lymph nodes and surrounding fatty tissue.
What does a subtotal colectomy involve?
Removal of the majority of the colon, for cancers on both the left and right side of the colon, preventative measure for patients with FAP or lynch syndrome or removing colon damaged by inflammatory bowel disease.
What is an abdominoperineal resection?
Abdominoperineal resections are performed for very low rectal cancers or severe perianal Crohn’s disease. It involves an abdominal approach either open surgery or laparoscopic for rectal dissection and end colostomy (stoma) formation where the descending colon ends.
Perineal approach can be performed excises the anus and complete rectal dissection.
The end result is removing the perineal skin, anal sphincter, rectum and sigmoid colon.
What are common complications of abdominoperineal resection?
- Bleeding
- Damage to local structures
- Resection of other organs
- Anaesthetic risk invovles damage to teeth, throat and larynx nausea and vomiting and cardiovascular/respiratory complications.
What is an early complication post-surgery?
Pain, risk of wound infection, UTI, scarring, DVT
What are the long-term complications of bowel resection?
ileus
Anastomotic leak
Incisional hernia
DVT and PE
Adhesions
Sexual and bladder dysfunction
What is ileus?
stasis of bowels occurring 2-43 days post surgery which lasts 24 hours but may be longer. It may be necessary to drain the stomach contents until the bowel is resumed functioning. To avoid this, minimise contamination and bowel handling and correct electrolyte imbalances post-operatiely.
What are the features of ileus?
Ileus can cause an intolerance to appetite and can also occur in severely ill patients with septic shock or mechanical ventilation. The small bowel is the first to return to function, followed by the stomach and then the colon. The cause of ileus is opioid use, Intraductal-abdominal inflammation, bleeding and open surgery. There is activation of a local inflammatory response from the stress of surgery and manipulation of the bowels that causes a sustained inhibitory sympathetic activity.
What is the clinical presentation of ileus?
Clinical presentation is abdominal distention and bloating with a slow onset, diffuse pain and inability to pass flatus. The patient will be tympanic on physical; exam, and with mild diffuse tenderness.
What is the difference between ileus and bowel obstruction?
ileus has absent/quiet bowel sounds in the early phase and slow onset of abdominal bloating.
What are the investigations for ileus?
Investigations include CT scan which will show dilated small bowel loops, with contrast for determining transition point. Treatment includes bowel rest, IV fluid therapy with parenterally nutrition and nasogastric compression. Prevention of ileus is with post op analgesia with epidural catheter, gum-chewing,, laxatives and prescribing peripheral opioid antagonist.
What does an anastomotic leak result in?
Risk of peritonitis. To prevent this, there should be good blood supply at te anastomosis and the bowel should not be under tension.
What is incisional hernia?
Incisional hernia, where perforation of the bowel occurs due to an incompletely-healed surgical wound. Indications include coughing producing a bulge at the site of incision and there is increased risk of obstruction, strangulation of the bowe and incarceration, where the bowel conten becomes trapped in the opening which can result in adhesions forming.
How can incisional hernia be prevented?
To prevent this, ensure fascia is tightly closed with the small bites technique, by making incisions between 5-8mm and interval of 5mm. this technique improves wound healing and strength and reduces risk of infection.
What are adhesions?
irregular boats of scar tissue may form between abdomnal tissues and organs. Majority of patients are asymptomatic, however there is a risk of intestinal obstruction and chronic abdominal or pelvic pain may occur as a result.
This may result in infertility in women due to interfering with ovum capture and transport. Opiates should be avoided in its management due to causing reduced bowel function.
What is a feature of adhesions on imaging?
Imaging may show “fat-bridging sign” where cord forms connection across the periotneum. Treatment is typically surgery.
What condition may occur due to prolonged bed rest after surgery?
DVT and PE.
What is the management strategy for adhesions?
Surgery.
What is the risk associated with low anterior resection?
Fecal incontinence and leakage.
What is a common complication of bowel resection?
Ileus.
What is the role of dietary management in low anterior resection syndrome?
High fiber diet.
What is the purpose of a J pouch?
Acts as a replacement for the rectum.
What is volvulus?
twisting of the intestine and mesentery, which compromises blood supply. It typically happens at the sigmoid colon due to a long mesentery. They will present with abdominal distention and absolute constipation and abdominal pain. Abdomen will be dissented and tympanic to percussion.
What are the risk factors with volvulus?
Risk factors are older age, male, reduced mobility, neurological disorders like Parkinson’s and people on antipsychotics.
What are the diagnostic findings for volvulus?
Venous blood gas should e performed to check pH and serum lactate. Diagnosed with CT imaging showing a whir sign, where sigmoid colon and mesentery are twisted. Radiograph will show coffee-bean sign in left iliac fossa management is fluid resuscitation and sigmoid colectomy with Hartmann’s procedure
What is stercoral colitis?
Stercoral colitis is an inflammatory colitis when faecalith impaction causes colon distention and results in faecalith/faecaloma forming which compresses on colon wall and may cause colonic necrosis, distention and ischaemia.
what is the common site of stercoral colitis?
It commonly occurs i the sigmoid colon and rectum during chronic constipation because the rectosigmoid colon is the narrowest part of the colon and stool here has decreased water content it can cause diffuse compression of veins, decreased outward blood flow and intramural oedema.
What is a risk of stercoral colitis?
There is a. Risk of bowel ischaemia or perforation, whih can lead to sepsis, so VBG should be ordered for lactic acid and anion ga metabolic acidosis and WCC. CT abdomen and pelvis with IV contrast will show faecal impaction and colon dilatation.
What is the treatment of stercoral coltiis?
manual disimpaction of rectum or endoscopically guided disimpaction. Avoid pain control with opiates. Signs of sepsis or shock, IV resuscitation and broad spectrum IV antibiotics to cover gram-negative and anaerobic organisms. Surgical management includes resection of affected bowel and formation of Hartmann pouch. Longterm management is dietary changes to increase fluid and fibre intake
