Colorectal Cancer Flashcards
What are the predisposing factors for colorectal cancer
- neoplastic polyps
- IBD (UC and CD)
- genetic predisposition (<8%) - e.g. FAP (familial adenomatous polyposis) and HNPCC (Hereditary nonpolyposis colorectal cancer)
- diet - low intake of fibre, high intake of red and processed meats
- alcohol
- smoking
- previous cancer
what can reduce incidence of colorectal cancer
- Aspirin >75mg/d reduces incidence and mortality
who tends to have more proximal cancers and who tends to have more distal cancers
- Black females tend to have more proximal cancers
- white men have more distal cancers
How does a left sided colonic cancer present
- PR bleeding/mucus
- altered bowel habit or obstruction (25%)
- tenesmus
- PR mass (60%)
How does a right sided colonic cancer present
- weight loss
- anaemia
- abdominal pain
- obstruction is less likely
What are symptoms that both left and right sided colonic cancer present
- abdominal mass
- perforation
- haemorrhage
- fistula
What investigations do you do for colonic cancer
- FBC - shows microcytic anaemia
- faecal occults blood (FOB)
- sigmoidoscopy or colonoscopy
- LFT + Liver MRI/US
- CEA (Carcinoembryonic antigen) - may be used to monitor disease and effectiveness of treatment
- if family history of FAP refer for DNA test once >15 years
Describe the T staging of colon cancer
- Tx - primary tumour cannot be assessed
- Tie - carcinoma in situ
- T1 - invading submucosa
- T2 - invading muscular propria
- T3- invading subserosa and beyond (not other organs)
- T4 - invasion of adjacent structures
Describe the N stages of colon cancer
- Nx - nodes cannot be assessed
- N0 - no node spread
- N1 - metastases in 1-3 regional nodes
- N2 - Metastases in >3 regional nodes
name the 4 stages of colon cancer
- Stage 1 = T1 or T2/N0/M0
- Stage 2. = T3 or T4/N0/M0
- Stage 3 = N1 or N2 but still M0
- Stage 4 = M1
Name the type of surgery that can take place for colon cancer
- Laparoscopic surgery
- endoscopic stenting
How does surgery effect colon cancer
- aims to cure and may increase survival times by up to 50%
name the types of laparoscopic surgery
- Right hemicolectomy – caecal, ascending or proximal transverse colon tumours
- Left hemicolectomy – distal transverse or descending colon tumours
- Sigmoid colectomy – sigmoid tumours
- Anterior resection – low sigmoid or high rectal tumours
- Abdomino-perineal (AP) resection – tumours low in the rectum (≤8cm from anus): permanent colostomy and removal of rectum and anus
- Hartmann’s procedure – in emergency bowel obstruction, perforation or palliation
- Transanal endoscopic microsurgery – local excision through a wide proctoscope for localised rectal disease
- Surgery with liver resection – may be curative if single-lobe hepatic metastases and no extrahepatic spread
when should endoscopic stenting be considered
- considerd for palpitation in malignant obstruction and as a bridge to surgery in acute obstruction
what are the benefits for endoscopic stenting
- reduces need for colostomy
- has less complications than emergency surgery
- shortens intensive care
- reduces total hospital stays
- prevents unnecessary operations
When is radiotherapy used in colonic cancer
- mostly used in palliation
- occasionally used in pre-op in rectal cancer to allow resection
- post-op only used in patents with rectal tumours at high risk of local recurrence
What stages is chemotherapy used in colonic cancer
Stage 3 disease: reduces disease recurrent by 30% and mortality by 25%
Stage 2 disease: benefits more marginal and warrant individualised approach
What chemotherapy agents are used in colonic cancer
FOLFOX regiment
- fluorouracil
- Folinic acid
- Oxaliplatin
What biological therapies are used in colonic cancer
Bevacizumab (anti-VEGF) improves survival when added to combination therapy in advanced disease
Cetuximab + Panitumumab (anti-EGFR) improve response rate and survival in KRAS wild-type metastatic colorectal cancer
What is the prognosis of colon cancer
Survival dependent on age and stage
- Stage 1: 5yr survival is 75%
- Stage 4: 5yr survival is 5%
What is the NHS bowel cancer screening programme
- On off flexible sigmoidoscopy offered to all people in their 55th year
- Colonoscopy to all men and women aged 60-75 who test positive for FOB using a home testing kit performed every 2 years
- target screening to those in the highest risk groups
- rate of death reduced by 16% in those undergoing screening
What are the three different types of stoma
- colostomy
- ileostomy
- urostomy
What are the complications of stoma
- Skin irritation
- dehydration
- leakage
- bowel obstruction
- retraction
- necrosis
