Table of Contents
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Surgery
Local Failure After Surgery Alone[1] [4]
T Stage | Local Failure Rate with APR/LAR only |
Local Failure with TME |
---|---|---|
T1 | 4-12% | ~5% |
T2 | 12-28% | ~20% (8%-48%) |
T3 | 36-79% |
Surgical Techniques
Low Anterior Resection (LAR)
- removes rectal cancer, adjacent normal tissue, and surrounding lymph nodes
- incision is made in the lower abdomen
- temporary colostomy
Abdominoperineal Resection (APR)
- remove rectal cancer, adjacent normal rectum, rectal sphincter or anus, and surrounding lymph nodes
- incision is in the lower abdomen and the perineum
- permanent colostomy
- Tumors < 5 cm from anal verge have traditionally required APR
Total Mesorectal Excision (TME)
- sharp dissection along the mesorectal fascia to remove the rectum and its surrounding adventitia en bloc
- mesorectum contains the blood supply and the lymphatic drainage for lower, middle and upper rectum
- consequence of TME can be bladder and erectile dysfunction
- TME resulted in marked decrease in local recurrence rates to 1.6-17.8%[3]
- The type of primary operation, LAR or APR, does not seem to affect the LR rate.
Transabdominal Resection
- Abdominoperineal resection (APR) or low anterior resection (LAR) using total mesorectal excision (TME)
Transanal Excision
- no incisions
- instruments though the anal opening
- a type of wide local excision
Lymph Node Assessment
- 7-14 lymph nodes need to be assessed per Rectal Intergroup Trial 0114.
Radiation Issues
Comparison of Pre-operative vs. Post-operative Radiation:
Advantages to Pre-op
- convert APR to a sphincter sparing procedure
- oxygenated tumor bed
- no tumor spill
- lower dose
- smaller fields
- less bowel in the field.
Advantages to Post-op
- pathologic staging
- spare the 10-15% patients with T1-2 tumors adjuvant treatment
- tumor bed located by clips.
Pre-operative Radiation
Summary
- Improves local control (~ 10%) and DFS (~ 5%) for doses of RT > 30 Gy BED
- Surival beneift is uncertain
- Some randomized trials show improved OS
- (Swedish Trial (NEJM 97), EORTC, Stockholm II)
- In one meta-analysis DFS benefit was cancelled by equivalent early non-cancer deaths
- A 2nd meta-analysis by Camma did show a overall survival benefit (p = 0.03)
- but absolute % benefit was not given.
- Some randomized trials show improved OS
Post-op Radiation
- Local control benefit with post-op radiation
- 2 of 5 randomized trial showed local control benefit with radiation
- NSABP B-01 (46-47 Gy) and MRCRWP
- NSABP is the trial to give continuous course of radiation using modern techinques.
Pre- vs. Post-operative ChemoRT Trials (Randomized)
Summary of German Rectal Cancer Study Group (NEJM 2004) and Swedish Trial
- No difference in DFS or OS
- Improved sphincter sparing and local control with pre-operative chemoradiation
Combined modality treatment
GITSIG:
202 patients T3 and or N+ randomized to
1) surgery alone 2) post-op RT alone 3) chemotherapy alone 4) post-op RT + 5Fu/CCNU.
Patients receiving CMT did better than surgery alone with survival at 54% vs. 27%.
No difference between RT, chemotherapy, or surgery alone groups.
Mayo-NCCTG 79-47-51:
Post-op RT vs. RT + chemotherapy and
combined group showed improved LC (14% vs. 25%), DFS (63% vs. 42%), and control of DM rate (30% vs.46%).
Do not use post-op RT alone.
Chemotherapy Issues
Continuous Venous Infusion
- When combined with radiation, continuous 5-FU has 10% DFS and 10% OS benefit over bolus 5FU (INT 86-47-51)
INT 86-47-51 (NCCTG)[7]
- Continuous (PVI) 5-FU 225 mg/m2 over 24 h 7 d/wk during RT vs. Bolus 5-FU concurrent with RT
- DFS 63 vs 53 (0.01) in favor of PVI + RT
- OS 70 vs 60 (.005) in favor of PVI + RT
- No difference in local control
Post Operative Therapy
- Post operative chemotherapy is required in all patients receiving pre-operative therapy regardless of pathology.
- (Need for post-operative therapy may be based on colorectal trials, just 2 trials listed below)
- NSABP C-01 MOF OS advantage over surgery alone (p = .05).
- NSABP C-03 OS-3 years was superior for the post-op 5-FU/leucovorin arm vs MOF (84% vs. 77%; P = .003).
- NCCN recommendation is for 5FU (380 mg/m2/day) + leucovorin(20mg/m2) days 1-5 q 28 days for 4 cycles.
Treatment and Outcome by Stage
Very Favorable Rectal Cancer
Risk Factors
- T1 N0
- < 30% of circumference
- < 3 cm, mobile
- < 8 cm of anal verge
- No LVI, PNI, or poor differentiation
Treatment
- transanal resection
Results
- Local failure is <10%.
Early Rectal Cancer
Risk Factors
- T1/T2 N0 Tumors that are not very favorable early rectal cancer
Treatment
- Transabdominal Resection
- No radiation
- No chemotherapy
Results
- Local failure rate and nodal incidence vary depending on report (see table above).
Locally Advanced Tumors
- cT3 patients should receive pre-operative chemoradiation (not post-operative) based on the German trial.
Unresectable
- pre-operative chemoradiation to convert it into a resectable lesion
- 40-60% can become resectable.
- Despite high-rate of conversion the local failure is about 25-55%.
Specific Issues
Sphincter Preservation
- Tumors < 5 cm from anal verge have traditionally required APR
- Pre-operative treatment with RT and CT can "convert" APR to LAR ~70% of the time.
8 prospective nonrandomized trials of patients who were declared to need an APR. All used conventional RT doses and techniques. 3 used RT alone (5 used combined modality). NSABP R-03 had 23% sphincter preservation rate. Lyon had 44% sphincter preservation rate. Others had ~ 70% sphincter preservation rate. [2]