Rectal Cancer Flashcards
What is TME?
Procedure performed during low anterior resection for middle/low rectal tumor, in which mesorectum is removed along with rectum to the level of elevators
Evidence for TME
reduce risk of local recurrence improves survival (5 year and overall disease free survival)
Landmark: Heald Lancet 1986)
Quirke grading of TME specimen
1) Gradings
2) Criteria
3) Evidence
1) 3-Good, 2-Moderate, 1-Poor
2)
- intactness of mesorectum
- defects in specimen
- bulk
- coning
- irregularity of CRM
3) Quirke 2009 Lancet
Clearance margins for rectal tumors
Distal 2cm mucosal margin
Proximal 5cm
CRM >2mm
Excision of CRM 5cm beyond distal margin
Defunctioning stoma, pros and cons of
1) loop ileostomy
2) transverse colostomy
1)
+less risk of prolapse
-high output stoma
2)
- prolapse
-risk of compromised marginal artery on closure
Low rectal cancer
MRI confirms lower edge of tumor below origins of the levator
TAMIS
use of single-site port transanally in conjunction with ordinary laparoscopic instruments/camera, standard lap CO2 insufflator
What is the mesorectum?
perirectal tissue composed of fat, lymphatics and blood vessels contained within the endopelvic visceral fascia, extending the whole length of rectum down to pelvic diaphragm and attaches the rectum to pelvic sidewall and sacrum
Indications for local excision of early rectal cancer
T1N0 or less
well - mod diff tumor
size < 4cm
clear margin feasible
tumor involving < 30% rectal wall circumference
Evidence for MRI for assessment of CRM involvement
MERCURY study (BMJ 2006)
MRI 92% specificity for predictions of clear CRM
Preoperative CRT for rectal cancer
1) Advantages
2) Disadvantages
1)
-sterilization fo mesorectal lymphatic channels
-downstaging
-exclusion fo small bowel from radiation field
-superior function of non-irradiated neo-rectum
2)
What is SCPRT? What is the regimen?
Short course preoperative radiotherapy
- 25 Gy total dose at 5Gy/fraction during 1 week
- Followed by immediate surgery <10 days after first radiation fraction
What is the regimen of long course chemoradiotherapy?
- 1.8-2Gy over 25-28 days with concurrent chemo as radiosensitizer
- Radical surgery delayed for 6-8 weeks
What is pCR? What percentage of patients achieve pCR after neoadjuvant chemo?
Pathological complete response
25%
T3a
<1mm invasion beyond muscularis propria
T3b
1-5mm invasion beyond muscularis propriae