Colon CA - Adjuvant Flashcards
How does Leucovorin work?
- By increasing the intercellular pools of 5,10 methylenetetrahydrofolate
- hence increasing the extent and duration of thymidylate synthetase inhibition
- This is one main mechanisms of 5FU
What increases the risk of colon cancer?
1) Polyposis Syndromes
- Familial Polyposis
- Peutz Jeghers
- Juvenile polyposis
2) Non-Polyposis Syndromes
- HNPCC
3) Other
- Inflammatory bowel disease
- prior colon cancer
- prior polyps
- first-deg relative Dx when
How does the mutation in FAP result in colon cancer?
APC is the Gene affected.
- APC is a key regulator of the wnt-signaling pathway
Mutation of APC Gene leads to the formation of a dysfunctional protein.
The dysfunctional protein cannot bind to beta-catenin.
Free beta-catenin can then activate the transcription of various oncogenes
Result is 100s-1000s of colonic polyps, predisposing to malignant tumors at a young age.
~0.5-1% of overall CLR CA
APC or beta-catenin mutations activating the want-signaling pathway have been found in 80-85% of sporadic colorectal CA
How did we come to use Oral Capecitabine as adjuvant treatment for colorectal cancer?
In met setting, Cape was established as an alternative to Bolus 5FU+Leucovorin.
Study by Twelves et al NEJM 2005 N=2000 resected stage III colon cancer 2 groups: A) Oral Capecitabine B) Bolus 5FU +Leucovorin (Mayo clinic regimen) 24 weeks
Results:
- Cape improved RFS HR 0.86, a/w sig fewer adverse events than 5FU+Leu
In which group of patients are the indications to start adjuvant chemo in strong? (For stage II)
(T.I.P.O)
T4 lesions
Inadequately sampled LN
Perforation at tumor site
Obstruction
What are considered walk indications to start adjuvant chemo in Stage II?
Poorly diff adenoCA
Lymphovascular invasion
High pre-op CEA
Peri neural invasion
What is the 5y survival in Stage III Colon CA with + LN?
30-50%
What are the studies in support of adjuvant chemotherapy for stage II CLR CA?
1) Netherlands Adjuvant Colon Cancer Project
2) QUASAR1
3) MOSAIC
4) NSABP pooled analysis (non-RCT)
5) Japanese meta-analysis (non-RCT)
Tell me about the Netherlands Adjuvant Colon Ca Project?
N=1000, Colon CA 700, Rectal Ca 300
45% stage II, 55% stage III
S/p curative surgery
Then randomized to 2 arms:
1) 1 y 5FU/Levamisole
2) Observation
RESULTS:
Improved 5yOS for both stage II and III
- Stage II 80% vs 70%
- Stage III 55% vs 40%
Trial had closed early
What is Levamisole?
An anthelmintic immunomodulator
What is the active metabolite of Fluorouracil?
Fluorodeoxyuracil monophosphate
Tell me about the profile of the patients enrolled in QUASAR
N=3300
Treatment naive
S/p curative resection
Stage I/II/III
70% Colon Ca,
8% Stage III, 90% Stage II, 0.5% Stage I
10% T4 tumors
What were the results of the QUASAR study (arm comparing adjuvant vs no adjuvant)
Relative risk of recurrence HR 0.78 in favor of chemo for Stage II
- 0.7 for rectal cancer
Absolute improvement in survival of 3.6% in Stage II
What was the treatment regimen with Oxaliplatin used in the MOSAIC study
2-Hr Leucovorin (200) D1,2
Bolus 5FU (400) D1,2
22-Hr CI 5FU (600) D1,2
2-Hr Oxaliplatin (85) D1
Q14 days X 12#
Tell me about the profile of the patients in MOSAIC Study
N=2300
Stage III 60% - 1-3 LN 45% - 4 or more LN 15% Stage II 40% - High risk Stage 2 25%, 15% not T4 20%
What are the results of the MOSAIC study? (6y update)
5y DFS 73% vs 67%
- Stage 3 66% vs 59%
- Stage 2 84% vs 80%
6y OS 78.5% vs 76%
- Stage 3 73% vs 69%
- Stage 2 87% vs 87%
Summarize the 4 NSABP studies
NSABP C-01: MOF > Observation
- 3% OS Benefit, p =0.7
- OS 72 vs 75%
NSABP C-02 = PVI 5FU > Obs
- OS 76% vs 88%, 12% OS benefit, p sig.
NSABP C-03 = 5FU/LV > MOF
- 8% OS benefit 84% vs 92% p sig
NSABP C-04 = 5FU/LV > 5FU/LEV
- 4% benefit 81% vs 85% p not sig
What stage is T4N0M0
Stage 2B
What stage is T3N0M0?
Stage 2A