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
T3c
6-15mm invasion beyond muscularis propria
T3d
>15mm invasion beyond muscularis propriae
What is cCR?
Clinical complete response
- absence of any palpable tumour or
- no irregularity at DRE,
- no visible lesion at proctoscopy except a flat scar/ telangiectasia / whitening of the mucosa.
What is watch and wait approach?
Non operative strategy of intensive surveillance after achieve pCR
What is the optimal time after CRT for surgery?
6-12 weeks
Shorter: inadequate tumour shrinkage, side effects from CRT
Longer: fibrosis leading to higher surgical morbidity, disease progression
Theoretical advantages of neoadjuvant chemoradiotherapy
- downstaging to allow resectiability + sphincter preservation
- sterilization of mesorectal lymphatics
- radiosensitizer
- better function of the non-irradiated neorectum
Theoretical disadvantages of preop CRT
- Pathological understanding leading to subsequent under-treatment
- tumor progression between period of neoadjuvant tx and surgery
- perioperative complications
Choice of chemotherapy with RT
Fluoropyrimidine
- 5-FU
- Capecitabine
Choice of chemotherapy with RT
Fluoropyrimidine
- 5-FU
- FOLFOX: infusional 5FU
- XELOX: infusional + oral
- FLOX: bolus 5FU
- Capecitabine
Evidence for SCPRT
- Swedish Rectal Cancer Trial 1997 NEJM
- Dutch TME Trial 2001 NEJM
- MRC (CR07) -NCIC (CTGC016)
Evidence for long course CRT
- German Rectal Cancer Study Group 2004 NEJM
- NASBP R-03
- Korean trial
What is TNT?
Total neoadjuvant therapy
oxaliplatin-based chemotherapy combined with long-course CRT or short-course RT
for locally advanced rectal cancer, with high risk for margin positive resection
Complications of acute toxicity in RT
- GI disturbance
- Radiation enteritis
- Lethargy/weakness
- Leukopenia
- Skin reaction
Late complications of RT
- Bowel stricture
- Chronic diarrhea
- Thromboembolism
- AVN of hip
- Secondary cancer
- Pelvic floor dysfunction
- Infertility/ Erectile Dysfunction / Dyspareunia
Purposed of colonic stenting
Bridge to surgery
Palliative intent
Advantages of stenting for bridge to surgery?
- Convert emergency to elective, reduce surgical mortality
- Allow nutrition boost
- Time for full bowel evaluation
- lower stoma rate
Risks of stenting
- Perforation 5%
- Bleeding 5%
- Stent migration 5-10%
- Stent occlusion
- Technical success 70-90%
- Mortality 0-1 %
Time to surgery after stenting
5-10 days (ESGE guidelines)
Some centres up to 2-4 weeks
Concerns with stenting
Oncological risk: Several RCT/prospective studies show higher recurrence rate
No different in overall survival
Would you recommend stenting as bridge to elective surgery?
In general as evidence points to worsening disease free survival, stenting as bridge to elective surgery not recommended compared to emergency surgery EXCEPT in selected cases of left sided obstructing tumor where patient high risk of postoperative mortality (ASA III, Age > 70)
Contraindications to stenting
Peritonitis
Suspected perforation
Low rectal tumors
Median duration of stent patency
106 days (68-288)
Surveillance after resection of colorectal cancer
- FU 4-6wks after surgery
- Minimum 2 sets of CT TAP in first 3 years
- CEA at least 6mthly in first 3 yrs
- CLN 1 year after OT then 5 years then dependent on CLN findings
- Reinvestigate prn if clinical/ radiological/ biochemical suspicious of recurrence
What is the management of local recurrent of rectal cancer?
- MDT
- Curative surgery vs +/- neoadjuvant if no hx of RT
- Aim R0 resection
- Inoperable => palliative CRT
