Oncology- colorectal cancer Part 2

Mangement:

Surgery of primary disease

• It is the mainstay for colorectal cancer. A segment of colon is removed with its blood supply and draining nodes excised. At least 5 cm margin of grossly negative colon is adequete and at least 12 LN for pathological evaluation.
• Obstructing tumors - primary resection. Consider intial decompression(proximal colostomy) or stent.
• Perforated colon cancer
• Rectal cancer - Local recurrence rates(less than 10%) using the total mesorectal excision(TME) [rectum is encised en bloc with the adjacent perirectal tissue for rectal cancers.
• A proportion of patients are suitable for metastatectomy after initial chemotherpay for liver mets. Radioablation shows promise.

Chemotherapy

• 5 fluorouracil or capecitabine therapy for patients with lymph node involvment increases 5-year survival from 64% to 71%. the addition of oxoliplatin improves survival.
• In metastatic cancer, 5 fluorouracil increases survival benefit from 6 to 12 months. The addition of oxaliplatin prolongs survival benefit to 18 months.

Biological therapy

• Anti-VEGF therapy(bevaciumab)
• anti-EGF(cetuximab)
  

Radiotherapy

• not routine.
  
• Adjuvant therapy
• neo-adjuvant therapy
• pallitive for local recurrence of rectal cancer.

Stage 0-1: surgery
Stage 2: + chemotherapy
Stage 3: +radiotherapy.
Stage 4:targetted therapy

Treating of symptoms

• Liver metastases- may cause pain. treat with NSAIDS or steriods. Hepatomegaly can cause squashed stomach syndrome lead to gastric fullness. treat with metoclopramide.
  
• perineal and pelvic pain- usually a neuropathic component to the pain. tenesmus. Requires intervention by palliative care doctors or anaesthetists.
  
• bowel obstruction-

1. Do a CT scan or barium enema to delineate the site of the obstruction and whether its multiple level to determine managment strategies
   
2. Surgical option involves putting a colonic stent via endoscopy or creating a stoma for for inoperable or recurrent cancers, low rectal cances. Multiple blocks are not amenable to surgicaltreatment
3. Medical treatment involves a syringe driver ad a mixture of analgesics, anti-emetics and anti-spasmodics.

• fistulae- between bowel and skin or bladder.
  
• rectal discharge and bleeding- refer to a oncologist as radiotherapy may help.
  
• hypoproteinaemia- common due to poor intake and por absorption. Lower limb odema
  
• poor apetite- treat with steriods.