Prof. Julien Taïeb Georges Pompidou European Hospital Paris, France Should MSI be determined in all patients with stage II and III colon cancer? Prof. Julien Taïeb Georges Pompidou European Hospital Paris, France

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Mutation on target genes Two major pathways for colorectal cancer carcinogenesis Chromosomic instability (LOH, MSS) Activation -catenin et KRAS Inactivation SMAD4, p53 et E-cadherin 85% Normal Epithelium Adenoma Early Carcinoma Late Cancer ? ? ? 15% TGF-RII, Bax , IGFIIR, MSH3 MSH6, TCF-4, Axin-2, Caspase-5, PTEN, WISP-3, RAD50 , RIZ … Genetic Instability (MSI) Deficient MMR Mutation on target genes Hamelin, Bull Cancer 2008 MSI : microsatellite instability; MSS : microsatellite stable; MMR : Mismatch Repair

(HMLH1 promoter methylation) Consitutional Mutation MSI COLORECTALCANCER 2/3 1/3 HEREDITARY HNPCC (Lynch syndrome ) SPORADIC Early Late BRAF Mutation 50-60% Somatic Inactivation Of a MMR gene (HMLH1 promoter methylation) Consitutional Mutation Of a MMR gene (MLH1, MSH2, MSH6, PMS2) MSI : microsatellite instability; MMR : Mismatch Repair Parsons, J Med Genet 2012

Lack of protein expression How to determine MSI status? Immuno-histochemistry Molécular Biology (PCR) MMR Protein Expression (MLH1, MSH2, MSH6 et PMS2) → microsatellite markers (BAT25, BAT26, NR21, NR24, NR27) => MSI tumor Lack of protein expression => MSI tumor Protein Expression => MSS tumor Anti MLH1 antibody => MSS tumor 96% concordancy

KRAS Mutation and Microsatellite Instability (dMMR) Incidence 532 resected CRC Nash GM et al. Ann Surg Oncol. 2010 Feb;17(2):416-24

Is MSI status determination useful? Genetic disease screening MSI Prognostic role (natural history of the disease) Predictive role (in relation with treatments)

Is MSI status determination useful? Yes! What for? Screening lynch syndrome? Prognostic impact for stage II? Stage III? Predictive value for treatment efficacy 5FU? Oxaliplatin?

Genetic disease screening

A proposed Lynch Synd diagnostic algorithm Selective screening is currently debated More ¼ of cases will be missed Universal IHC (+/- MSI) altered IHC or MSI + Normal IHC and no MSI MLH1(-) MSH2(-) MSH6(-) PMS2(-) R Salazar ESMO- WCGIC 2012 MLH1 hypermethylation or BRAF V600E BRAF V600E - + Germline genetic testing STOP This is where all footnotes and references go.

Prognostic value

Risk of death decreased of 35% in MSI patients MSI : prognostic value? Popat et al, 2005 : OS and MSI Meta-analysis of 32 studies , 7642 patients (1277 MSI) All stages HR=0,65 (95% CI; 0,59-0,71) Stage II-III HR=0,67 (95% CI; 0,58-0,78) Risk of death decreased of 35% in MSI patients

MSI : OS for stage IIA (T3N0) After surgery only Parc Y et al, Gut 2004 5 year DFS : 90% versus 70%; p=0,02 Multivariate analysis (age, gender, location, VELIPI, MSI status) : => MSI = independent prognostic marker VELIPI: vascular emboli, lymphatic invasion and perineural invasion

MSI in stage II and III patients treated with surgery alone Sargent DJ et al. J Clin Oncol. 2010 Jul 10;28(20):3219-26

Predictive value

MSI and adjuvant chemo with 5FU Reférence Type N patients (% MSI) Stage N patients with CT comparison Survival Benefit Elsaleh et al, 2000 R 656 (8.5) III 272 CT adj : MSS vs MSI MSI: chir seule vs CT adj 5 year OS Hemminki et al, 2000 P / NR 95 (12) 95 CT adj : MSS vs MSI 3 year DFS Ribic et al, 2003 CR 570 (16.7) II + III 283 5 year OS and DFS Carethers et al, 2004 204 (17.6) 66 MSI: chir seule vs CT adj OS De Vos Tot et al, 2004 92 (100) 28 Westra et al, 2005 ECR 273 (16) 273 5 year DFS Lanza et al, 2006 718 (15.9) 193 6 year OS Kim et al, 2007 542 (18) 369 Sargent et al, 2010 * 457 (15) 229 1027 (16) 512 Abréviations: Adj, adjuvant; CT, chimiothérapie par 5FU; NR, non randomisé; P, prospectif; R, rétrospectif; ECR, essai contrôlé randomisé; SSM, survie sans maladie; SSR, survie sans récidive; SG, survie globale. * Analyse poolée des données des études de Ribic et al + Sargent et al. BENEFIT NO BENEFIT Contradictory results Zaanan A et al, La Lettre du Cancérologue 2011

MSI : resistance to adjuvant 5FU? Meta-analysis , Des Guetz et al, EJC 2009 -> 3690 patients: stage III=75%, MSI=14% HR = 0.96 (95% CI, 0.62–1.49) NO BENEFIT

MSI : resistance to adjuvant 5FU? MSS NO BENEFIT of adjuvant 5FU for MSI patients stage III MSS MSI DELETERIOUS EFFECT of adjuvant 5FU for MSI patients stage II Sargent et al , JCO 2010

suspected germline mutations with suspected sporadic CRC Effect of 5-FU-based therapy on DFS dMMR colon cancer patients with: suspected germline mutations with suspected sporadic CRC 5FU No CT 5FU No CT 99 stage II and III patients 245 stage II and III patients 5FU may be efficient in patient with lynch syndrome but not in patient with sporadic MSI Sinicrope FA, Foster NR,Thibodeau SN, et al. DNA Mismatch Repair Status and Colon Cancer Recurrence and Survival in Clinical Trials of 5-Fluorouracil-Based Adjuvant Therapy. J Natl Cancer Inst 2011;103:863–875

Patients from the QUASAR trial Value of dMMR in predicting recurrence and benefits from chemotherapy in colorectal cancer with stage II Patients from the QUASAR trial Stage II Colon Hutchins G et al. J Clin Oncol. 2011 Apr 1;29(10):1261-70

And with FOLFOX?

MSI and adjuvant FOLFOX? HR 0.66, 95% CI 0.38 - 1.15; p=0.15 HR 0.17, 95% CI 0.04 - 0.68; p=0.01 MSS MSI 100% 80.3% 57.9% Disease-free survival probability 73.6% FOLFOX, 97 patients, 19 recurrences 5FU, 104 patients, 32 recurrences FOLFOX, 12 patients, 0 recurrence 5FU, 20 patients, 8 recurrences Time after surgery (months) Zaanan et al, Annals of Oncology 2010

MSI and adjuvant FOLFOX? 303 patients, Stage III, FOLFOX treatment P = 0.037 MSI is an independent prognostic marker in multivariate analysis DFS (%) HR, 2.11; 95% CI, 1.05-4.25 MSI, 34 patients, 3 events MSS, 269 patients, 74 events Year Zaanan et al, Clin Can Res 2012

C07 and C08: Mutation Profiling and Microsatellite Instability in Stage II and III Colon Cancer: An Assessment of Their Prognostic and oxaliplatin Predictive Value Gavin P G et al. Clin Cancer Res 2012;18:6531-6541

C07 and C08: Mutation Profiling and Microsatellite Instability in Stage II and III Colon Cancer: An Assessment of Their Prognostic and oxaliplatin Predictive Value MSI : prognostic factor with HR 0.48 for RFS MSI : non predictive for oxaliplatin (suggesting a similar benefit in pMMR and dMMR) Gavin P G et al. Clin Cancer Res 2012;18:6531-6541

Patients with or without blocks had equivalent RFS, DFS or OS!!! MSI and adjuvant FOLFOX? Results from the MOSAIC Trial Stage Endpoint MMR NA MMR OK HR [95% CI] P value N=1242 N=1004 II-III RFS, No of events 351 303 1.01 0.86-1.17 0.942 DFS, No of events 385 378 1.08 0.94-1.24 0.284 OS, No of events 322 309 0.97 0.83-1.13 0.740 MMR NA : MMR status not available; MMR OK : MMR status available Patients with or without blocks had equivalent RFS, DFS or OS!!! Fléjou JF, ASCO 2013

dMMR OS (Stage II and III) Endpoint LV5FU2 FOLFOX HR [95% CI] P value 5-yr OS, % (sd) 82.3 (5.3) 90.9 (4.3) 0.42 0.18-0.98 0.060 Fléjou JF, ASCO 2013

Stage II and III dMMR Fléjou JF, ASCO 2013

Conclusions dMMR MOSAIC Findings of these translational analyses in MOSAIC show Hazard Ratio in favor of FOLFOX4 vs LV5FU2 in dMMR colon cancer patients.   Low dMMR prevalence in stage II & III colon cancer limits conclusive evidence for oxaliplatin benefit in this population, even in this large study.  Analyses of colon cancer MMR status in patients included in the MOSAIC study support the use of FOLFOX4, in patients with dMMR stage III cancer ( but not in stage II?) Fléjou JF, ASCO 2013

Take home messages (I) MSI colon cancer is an heterogenous group Sporadic and LS-MSI may behave differently, BRAFmt and WT MSI also… MSI studies are difficult because of the low incidence of this characteristic, in different stages of the disease, with different standard treatment over time MSI is a genetic marker useful to screen out Lynch syndrome MSI shall be determined in all patients under 60 year old with a colorectal cancer MSI has a clear prognostic value for stage II colocrectal cancer patients MSI shall be determined in all patients resected from a stage II colon cancer to help in adjuvant treatment decision

Take home messages (II) MSI seems predictive of resistance to fluoropyrimidine in stage II and III patients (inconclusively) in exploratory analyses FOLFOX seems as efficient in MSI or MSS patients in stage III tumors Unanswered questions: Stage II patients T4 MSI with other bad prognosis factors??? Stage III patients contraindicated for oxaliplatin???

Algorithm for chemotherapy decision Colon cancer Stage II Stage III MSI MSS NO MSI Determination needed NO CT Good prognosis, resistance to FU CT may be discussed Regarding other prognostic factors, age, patient wish... FOLFOX

The Future Develop worldwide collaborations to obtain sufficient number of patients to address unanswered questions NSABP and MOSAIC will be pooled PETACC8 and NCCTG N0147 also