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PURPOSE: The microsatellite instability (MSI) or deficient mismatch repair (dMMR) phenotype is usually regarded as a single biologic entity, given the absence of comparative analyses regarding prognosis and response to chemotherapy between sporadic and familial dMMR cancers. PATIENTS AND METHODS: Patients with stage III colon cancers were randomly assigned to FOLFOX (leucovorin, fluorouracil, and oxaliplatin) with or without cetuximab in 2 large adjuvant phase III trials (N = 5,577). Among patients with MSI and KRAS exon 2 wild-type (WT) tumors, the prognostic and predictive impacts of sporadic versus familial dMMR cancers and BRAF V600E mutational status were determined. Multivariable Cox proportional hazards models were used to assess disease-free survival (DFS) by treatment arm, adjusting for age, sex, tumor grade, Eastern Cooperative Oncology Group performance status, pT/pN stage, and primary tumor location. RESULTS: Among patients with MSI status with complete data for dMMR mechanism analysis (n = 354), 255 (72%) had sporadic (BRAF mutation and/or MLH1 methylation) and 99 (28%) had familial tumors (BRAF WT and unmethylated MLH1 or loss of MSH2/MSH6/PMS2 protein expression). A large proportion of dMMR sporadic tumors were mutated for BRAF (n = 200). In patients treated with FOLFOX, DFS did not differ statistically by dMMR mechanism, whereas in patients treated with FOLFOX plus cetuximab, those with sporadic tumors had worse DFS than those with familial cancers (multivariable hazard ratio, 2.69; 95% CI, 1.02 to 7.08; P = .04). Considering the predictive utility, the interaction between treatment and dMMR mechanism was significant (P = .03). Furthermore, a nonsignificant trend toward a deleterious effect of adding cetuximab to FOLFOX was observed in patients with BRAF-mutant but not BRAF WT tumors. CONCLUSION: The addition of cetuximab to adjuvant FOLFOX was associated with shorter DFS in patients with sporadic dMMR colon cancer. Additional studies are needed to validate these results in metastatic disease.
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PURPOSE: Both concurrent chemoradiotherapy (CT-RT) and cetuximab radiotherapy (cetux-RT) have been established as the standard of care for the treatment of locally advanced squamous cell carcinoma of the head and neck. It was not known whether the addition of induction chemotherapy before cetux-RT could improve outcomes compared with standard of care CT-RT. PATIENTS AND METHODS: The current trial was restricted to patients with nonmetastatic N2b, N2c, or N3 squamous cell carcinoma of the head and neck and fit for taxotere, cisplatin, fluorouracil (TPF). Patients were randomly assigned to receive three cycles of TPF followed by cetux-RT versus concurrent carboplatin fluorouracil and RT as recommended in National Comprehensive Cancer Network guidelines. The trial was powered to detect a hazard ratio (HR) of 0.66 in favor of TPF plus cetux-RT for progression-free survival at 2 years. The inclusion of 180 patients per arm was needed to achieve 80% power at a two-sided significance level of .05. RESULTS: Between 2009 and 2013, 370 patients were included. All patients and tumors characteristics were well balanced between arms. There were more cases of grade 3 and 4 neutropenia in the induction arm, and the induction TPF was associated with 6.6% treatment-related deaths. With a median follow-up of 2.8 years, 2-year progression-free survival was not different between both arms (CT-RT, 0.38 v TPF + cetux-RT, 0.36; HR, 0.93 [95% CI, 0.73 to 1.20]; P = .58). HR was 0.98 (95% CI, 0.74 to 1.3; P = .90) for locoregional control and 1.12 (95% CI, 0.86 to 1.46; P = .39) for overall survival. These effects were observed regardless of p16 status. The rate of distant metastases was lower in the TPF arm (HR, 0.54 [95% CI, 0.30 to 0.99]; P = .05). CONCLUSION: Induction TPF followed by cetux-RT did not improve outcomes compared with CT-RT in a population of patients with advanced cervical lymphadenopathy.
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Purpose To investigate the effect of adding concurrent chemotherapy (CT) to cetuximab plus radiotherapy (RT; CT-cetux-RT) compared with cetuximab plus RT (cetux-RT) in locally advanced squamous cell carcinoma of the head and neck (LA-SCCHN). Patients and Methods In this phase III randomized trial, patients with N0-2b, nonoperated, stage III or IV (nonmetastatic) LA-SCCHN were enrolled. Patients received once-daily RT up to 70 Gy with weekly cetuximab or with weekly cetuximab and concurrent carboplatin and fluorouracil (three cycles). To detect a hazard ratio (HR) of 0.64 for progression-free survival (PFS) with 85% power at a two-sided significance level of P = .05, 203 patients needed to be included in each arm. Results Four hundred six patients were randomly assigned to either CT-cetux-RT or cetux-RT. Patient and tumor characteristics were well balanced between arms, including p16 status. With a median follow-up of 4.4 years, the HR for PFS favored the CT-cetux-RT arm (HR, 0.73; 95% CI, 0.57 to 0.94; P = .015), with 3-year PFS rates of 52.3% and 40.5% and median PFS times of 37.9 and 22.4 months in the CT-cetux-RT and cetux-RT arms, respectively. The HR for locoregional control was 0.54 (95% CI, 0.38 to 0.76; P < .001) in favor of CT-cetux-RT. These benefits were observed regardless of p16 status for oropharynx carcinomas. Overall survival (HR, 0.80; P = .11) and distant metastases rates (HR, 1.19; P = .50) were not significantly different between the two arms. The CT-cetux-RT arm, compared with cetux-RT, had a higher incidence of grade 3 or 4 mucositis (73% v 61%, respectively; P = .014) and of hospitalizations for toxicity (42% v 22%, respectively; P < .001). Conclusion The addition of concurrent carboplatin and fluorouracil to cetux-RT improved PFS and locoregional control, with a nonsignificant gain in survival. To our knowledge, this is the first evidence of a clinical benefit for treatment intensification using cetux-RT as a backbone in LA-SCCHN.
ABSTRACT
IMPORTANCE: The prognostic impact of DNA mismatch repair (MMR) status in stage III colon cancer patients receiving FOLFOX (folinic acid, fluorouracil, and oxaliplatin) adjuvant chemotherapy remains controversial. OBJECTIVE: To determine the association of MMR status with disease-free survival (DFS) in patients with stage III colon cancer treated with FOLFOX. DESIGN, SETTING, AND PARTICIPANTS: The evaluated biomarkers for MMR status were determined from prospectively collected tumor blocks from patients treated with FOLFOX in 2 open-label, phase 3 randomized clinical trials: NCCTG N0147 and PETACC8. The studies were conducted in general community practices, private practices, and institutional practices in the United States and Europe. All participants had stage III colon adenocarcinoma. They were enrolled in NCCTG N0147 from February 2004 to November 2009 and in PETACC8 from December 2005 to November 2009. INTERVENTIONS: Patients in the clinical trials were randomly assigned to receive 6 months of chemotherapy with FOLFOX or FOLFOX plus cetuximab. Only those patients treated with FOLFOX alone were included in the present study. MAIN OUTCOMES AND MEASURES: Association of MMR status with DFS was analyzed using a stratified Cox proportional hazards model. Multivariable models were adjusted for age, sex, tumor grade, pT/pN stage, tumor location, ECOG (Eastern Cooperative Oncology Group) performance status, and BRAF V600E mutational status. RESULTS: Among 2636 patients with stage III colon cancer treated with FOLFOX, MMR status was available for 2501. Of these, 252 (10.1%) showed deficient MMR status (dMMR; 134 women, 118 men; median age, 59 years), while 2249 (89.9%) showed proficient MMR status (pMMR; 1020 women, 1229 men; median age, 59 years). The 3-year DFS rates in the dMMR and pMMR groups were 75.6% and 74.4%, respectively. By multivariate analysis, patients with dMMR phenotype had significantly longer DFS than those with pMMR (adjusted hazard ratio, 0.73; 95% CI, 0.54-0.97; P = .03). CONCLUSIONS AND RELEVANCE: The deficient MMR phenotype remains a favorable prognostic factor in patients with stage III colon cancer receiving FOLFOX adjuvant chemotherapy. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00079274 for the NCCTG N0147 trial and EudraCT identifier: 2005-003463-23 for the PETACC8 trial.
