Oncology workshop 1 (colorectal cancer) Flashcards
Why is staging in cancer important?
- Prognosis
- Treatment
Why does staging change over time?
- Due to better treatment and investigations and technology
Explain staging in colorectal cancer (Dukes’ criteria)
- Dukes’ A Cancer has grown into the inner layer or muscle layer of the bowel wall Not spread to lymph nodes or other parts of the body
- Dukes’ B Cancer has grown through the muscle layer or outer layer May be growing into tissues near the bowel Not spread to the lymph nodes or other parts of the body
- Dukes’ C Cancer is any size and has spread to nearby lymph nodes Not spread to other parts of the body
- Dukes’ D Cancer is any size May or may not have spread to nearby lymph nodes Has spread to other parts of the body
Explain TNM staging
American Joint Committee on Cancer
- TX – Primary tumour cannot be assessed
- T0 – No evidence of primary tumour
- Tis – Carcinoma in situ: intraepithelial or invasion of lamina propria
- T1 – Invades submucosa
- T2 – Invades muscularis propria
- T3 – Invades through muscularis propria into subserosa or into non-peritonealised pericolic or perirectal tissues
- T4 – Directly invades other organs or structures and/or perforates visceral peritoneum
- NX – Regional lymph nodes cannot be assessed
- N0 – No regional lymph node metastasis
- N1 – Metastasis in 1–3 regional lymph nodes
- N2 – Metastasis in 4 or more regional lymph nodes
- MX – Distant metastasis cannot be assessed
- M0 – No distant metastasis
- M1 – Distant metastasis
Draw T staging
Explain grading in (colorectal) cancer
What does it look like under the microscope?
- Grade 1 (low grade)
- Cancer cells look similar to normal cells (well differentiated)
- Grade 2 (moderate grade)
- Cancer cells look more abnormal (moderately differentiated)
- Grade 3 (high grade)
- Cancer cells look very abnormal (poorly differentiated)
Draw the structure anatomy of the bowel
Explain the pathology in colorectal cancer
What is the most common pathology in colorectal cancer?
- Adenocarcinoma
- Well or moderately differentiated
Other pathologies?
- Mucinous carcinomas
- Colloid carcinomas
What else do we get in pathology report?
- Vascular or lymphatic invasion
- R0, R1, R2 (
- T N M (more than 12 nodes to accurately stage)
- Mutations (BRAF, KRAS, NRAS)
- MSI or MMR
What is MMR and MSI?
- Mismatch repair proteins (MMR)
- MLH1, MSH2, MSH6 or PMS2
- They keep your microsatellite (MSI) regions of your DNA stable
- Help prevent carcinogenic mutations
- If you are MMR proficient you are MSI-stable
- If you are MMR deficient you are MSI-instable
- If you are MMR proficient you are MSI-low
- If you are MMR deficient you are MSI-high
What is Lynch Syndrome?
- Hereditary non-polyposis colorectal cancer (HNPCC)
- Most common cause of hereditary colorectal cancer
- MSH2 and/or MSH6 loss suspicious for Lynch Syndrome
- Increased risk of lots of cancers
- Younger age (before 50)
- Uterine (endometrial)
- Stomach
- Liver
- Kidney
- Brain
- Surveillance? (as genetic history = family history)
- 2 yearly colonoscopies, annual endometrial US +-biopsy, 1-2 yearly OGDs (if +ve family history) → NOT NEED TO KNOW THIS BIT
What factors influence surgical treatment?
What factors influence surgical treatment?
- Location and spread of cancer (nodes and other organs)
- Blood supply
- Lymphatic drainage
- Patient fitness
- Patient choice!
Draw the blood supply to the bowel
Draw right hemicolectomy
Draw transverse colectomy
Draw an extended right hemicolectomy
Draw a left hemicolectomy
Draw a sigmoid colectomy
What to do with someone with metastatic disease (not for sugery) and presents with bowel obstruction?
- Colectomy
- Defunctioning stoma
- Colonic stenting
