Panitumumab (pmab) regimen evaluation in colorectal cancer to estimate primary response to treatment (PRECEPT): Effect of KRAS mutation status on second-line treatment (tx) with pmab and FOLFIRI

Purpose This randomized study assessed whether the best overall response rate (ORR) of cetuximab combined with oxaliplatin, leucovorin, and fluorouracil (FOLFOX-4) was superior to that of FOLFOX-4 alone as first-line treatment for metastatic colorectal cancer. The influence of KRAS mutation status was investigated. Patients and Methods Patients received cetuximab (400 mg/m2 initial dose followed by 250 mg/m2/wk thereafter) plus FOLFOX-4 (oxaliplatin 85 mg/m2 on day 1, plus leucovorin 200 mg/m2 and fluorouracil as a 400 mg/m2 bolus followed by a 600 mg/m2 infusion during 22 hours on days 1 and 2; n = 169) or FOLFOX-4 alone (n = 168). Treatment was continued until disease progression or unacceptable toxicity. KRAS mutation status was assessed in the subset of patients with assessable tumor samples (n = 233). Results The confirmed ORR for cetuximab plus FOLFOX-4 was higher than with FOLFOX-4 alone (46% v 36%). A statistically significant increase in the odds for a response with the addition of cetuximab to FOLFOX-4 could not be established (odds ratio = 1.52; P = .064). In patients with KRAS wild-type tumors, the addition of cetuximab to FOLFOX-4 was associated with a clinically significant increased chance of response (ORR = 61% v 37%; odds ratio = 2.54; P = .011) and a lower risk of disease progression (hazard ratio = 0.57; P = .0163) compared with FOLFOX-4 alone. Cetuximab plus FOLFOX-4 was generally well tolerated. Conclusion KRAS mutational status was shown to be a highly predictive selection criterion in relation to the treatment decision regarding the addition of cetuximab to FOLFOX-4 for previously untreated patients with metastatic colorectal cancer.

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Discordance of KRAS Mutational Status between Primary Tumors and Liver Metastases in Colorectal Cancer: Impact on Long-Term Survival Following Radical Resection

Cancers ◽

10.3390/cancers13092148 ◽

2021 ◽

Vol 13 (9) ◽

pp. 2148

Author(s):

Francesco Ardito ◽

Francesco Razionale ◽

Lisa Salvatore ◽

Tonia Cenci ◽

Maria Vellone ◽

...

Keyword(s):

Colorectal Cancer ◽

Liver Metastases ◽

Primary Tumor ◽

Kras Mutation ◽

Colorectal Tumor ◽

Term Survival ◽

Primary Tumors ◽

Mutation Status ◽

Primary Colorectal Tumor ◽

Kras Mutation Status

If KRAS mutation status of primary colorectal tumor is representative of corresponding colorectal liver metastases (CRLM) mutational pattern, is controversial. Several studies have reported different rates of KRAS discordance, ranging from 4 to 32%. Aim of this study is to assess the incidence of discordance and its impact on overall survival (OS) in a homogenous group of patients. KRAS mutation status was evaluated in 107 patients resected for both primary colorectal tumor and corresponding CRLM at the same institution, between 2007 and 2018. Discordance rate was 15.9%. Its incidence varied according to the time interval between the two mutation analyses (p = 0.025; Pearson correlation = 0.2) and it was significantly higher during the first 6 months from the time of primary tumor evaluation. On multivariable analysis, type of discordance (wild-type in primary tumor, mutation in CRLM) was the strongest predictor of poor OS (p < 0.001). At multivariable logistic regression analysis, the number of CRLM >3 was an independent risk factor for the risk of KRAS discordance associated with the worst prognosis (OR = 4.600; p = 0.047). Results of our study suggested that, in the era of precision medicine, possibility of KRAS discordance should be taken into account within multidisciplinary management of patients with metastatic colorectal cancer.

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