Lower GI part 1 Flashcards by Meg-Georgia-Teague -

What does the Lower GI consist of?

small bowel
colon
rectum
anus

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What are the 4 layers of the GI tract from inner to outer?

mucosa (epithelial)
Submucosa (connective tissue- contains blood and lymphatic vessels)
Muscularis (smooth muscle- involuntary contractions to break down food)
Serosa (serous membrane covering GI tract suspended in abdominal cavity

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What is the epidemiology & aetiology of the small bowel?

accounts for <5% of gastro-intestinal tumours
Malignant lesions occur frequently (duodenum &amp; jejunum)
Benign lesions (adenoma &amp; fibromas in ileum)

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What are the genetic/ hereditary predispositions for small bowel tumours

polyposis
Crohn’s disease
Gardner’s syndrome

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What are the signs & symptoms for Small Bowel cancer?

often silent for long time
abdominal pain/cramps
chronic anaemia
abdominal haemorrhage
abdominal mass
weight loss
diarrhoea

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How can cancers of the small bowel spread?

neighbouring organs

regional lymph nodes

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What is the pathology of small bowel cancer?

Adenocarcinomas (45%)
Carcinoid (30%)
Lymphomas (10%)
Sarcomas (mostly leiomyosarcoma)

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What is the clinical management of small bowel cancer?

primarily resection
post-op RT to tumour bed/ nodal areas
RT and Chemo
Whole abdo RT for lymphomas

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If the cancer of the small bowel is unresectable what treatment is used?

Chemo/RT or Pre-op RT

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How responsive to radiation are small bowel cancesr?

Generally poor radiosensitivity (except sarcomas)

20-25Gy +/- radiosensitings chemo (5FU or cisplatin based chemo)

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What are the general features of the Colon?

1.5m long
ileum to the anus
absorb water
transmit the waste material

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What is the epidemiology & aetiology for colorectal cancers?

2nd most commonly diagnosed cancer in Australia
Age
Diet
Alcohol, smoking, obesity, low physical activity

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What are the Genetic/ Hereditary predispositions associated with colorectal cancer?

Polyposis
Crohn’s Disease (inflammation of lining of GI tract)
Diverticulitis (pouches along colon become inflamed)

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What is the age bracket for colon/rectum cancers?

majority occur in the over 50s

Peak incidence 60 -80 years

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What dietary factors affect colorectal cancer (Aetiology)?

high meat, fat, calorie, alcohol intake

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What are the signs & symptoms of colorectal cancer?

palpable mass
rectal bleeding &amp;/or blood in stool
diarrhoea
change in bowel habit
Tenesmus (cramping rectal pain)
Obstructive symptoms
Iron deficiency anaemia
Weight loss
vomiting

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How can colorectal cancer be detected?

Faecal occult blood test
Digital Rectal Exam (DRE)
Sigmoidoscopy/ colonscopy

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How does colorectal cancer spread?

mucosal walls
lymph &amp; blood (submucosal layer)
Peritoneal Seeding
Pelvic lymph nodes 
Distant metastases

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What are the common sites of distant metastasis for colorectal cancer?

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Liver via blood
Lung via IVC embolism
Bone
Ovaries 
Adrenal

What are the different types of colorectal cancers?

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adenocarcinoma
Signet-ring Carcinoma
Squamous Cell Carcinoma

What staging is used for colorectal cancer?

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Dukes
Aster-Coller
TNM

What is Dukes Staging for colorectal cancer?

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A= no bowel penetration
B = bowel penetration
C= positive nodes
D= metastasis

What is stage A of Dukes Staging for colorectal cancer?

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A- Confined to bowel wall ie. musoca and submucosa or early muscular invasion

What is stage C of Dukes Staging for colorectal cancer?

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C1- lymph node involvement but not up to highest point of vascular ligation
C2- Nodes involved up to highest nodes at the point of vascular ligation

What is the TNM staging for colorectal cancer?

``` T1,2,3,4, T1 = submucosa T2= muscularis propria T3 = beyond 2 T4= other organs invaded N1,2 N1= 1-3 nodes N2= >3 nodes M1= metastatic ```

What are the clinical management options for colorectal cancer?

surgery radiotherapy chemotherapy

What are the factors to consider with RT for colon cancer?

Difficult to determine the volume to be irradiated | proximity to OAR

Surgery - colorectal cancer

primary definitive treatment | Total mesorectal excision (TME) (reduced local recurrence rate to <10% compared to 30% previously

What do the inferior mesenteric nodes drain?

Descending Colon Left side of mesentery Sigmoid Colon Rectum

What is the 5yr survival for the Grading for colorectal cancer?

``` G1-2 = 55% 5 yr survival G3-4 = 30% 5 yr survival ```

What is a Total Meso-rectal Excision (TME)

Remove the mesenteric fat and muscle around the rectum

How does distance from the ano-rectal junction affect TME?

If the rectal cancer is >5-6cm above the ano-rectal junction then can perform a low anterior resection and join the bowel together (anastomosis) If less than this then abdomino-perineal resection and permanent colostomy with closure of anus

What is the difference between short and long course of pre-op RT?

short course: doesn't allow for tumour downstaging) but doesn't delay surgery for as long, less side effects because tumour cut out 1 week after RT therefore before they experience these side effects Long course: 28 fractions, more side effects, RT affects healing of cells after surgery

What is the standard dose fractionation for short course (Swedish protocol) pre-op RT? (for rectum)

25Gy in 5 fractions over 1 week, surgery follows in next 7-10 days improvement 5 year survival

What is the standard fractionation for long course Pre-op RT for rectum

45-50.4Gy in 25-28 fractions over 5-6 weeks surgery follows approx 8-10 weeks later (downsizes tumour)

What is the lymphatic drainage of the Anus?

lymph from anal canal drains into superficial inguinal lymph nodes -> external iliac

What is the epidemiology & aetiology of anus cancer?

``` rare- 2% large bowel cancer slightly more common in women AIDS related HPV SCC (squamous cells) ```

What is the epidemiology & aetiology of anus cancer?

``` rare- 2% large bowel cancer slightly more common in women AIDS related HPV SCC (squamous cells) ```

What are the signs and symptoms of anal cancer?

visible or palpable mass bleeding pain &/or discharge Pruritus (itchiness) (more perianal)

How does anal cancer spread?

local invasion of anal sphincter and rectal wall | Prostate, bladder or cervix spread

What is the staging used for anal cancer?

AJCC (American joint cancer committee) (TNM) T size N nodes M metastatic

What is the Clinical Management of Anal cancer?

RT (only if chemo not tolerated) or Chemo/RT is primary option high survival rate looking to preserve anal sphincter (instead of removal -> colostomy bag) surgery for very early disease or post RT for recurrence Chemo Radiosensiting (5FU &/or mitomycin C)

What are the standard doses for anal cancer?

Ph 1: pelvis & nodes (30.6 - 45Gy with chemo) (2-4 fields) Ph 2: Primary site (add 24.4- 14.4Gy) (include superficial inguinal nodes)

What is the typical set-up for anal cancer?

mainly prone + belly board | can be supine

What is the typical set-up for anal cancer?

mainly prone + belly board

Lower GI part 1 Flashcards

(45 cards)