Sequential RAS mutations evaluation in cell-free DNA of patients with tissue RAS wild-type metastatic colorectal cancer: the PERSEIDA (Cohort 2) study.

PURPOSE: RAS (KRAS/NRAS) mutational status on a tumor biopsy is mandatory to guide the best treatment in metastatic colorectal cancer (mCRC). Determining the RAS mutational status by tumor-tissue biopsy is essential in guiding the optimal treatment decision for mCRC. RAS mutations are negative predictive factors for the use of EGFR monoclonal antibodies. Cell-free DNA (cfDNA) analysis enables minimally invasive monitoring of tumor evolution. METHODS/PATIENTS: PERSEIDA was an observational, prospective study assessing cfDNA RAS, BRAF and EGFR mutations (using Idylla™) in first-line mCRC, RAS wild-type (baseline tumor-tissue biopsy) patients (cohort 2). Plasma samples were collected before first-line treatment, after 20 ± 2 weeks, and at disease progression. RESULTS: 117 patients were included (103 received panitumumab + chemotherapy as first-line treatment). At baseline, 7 (6.8%) patients had RAS mutations, 4 (3.9%) BRAF mutations and no EGFR mutations were detected (cfDNA, panitumumab + chemotherapy subpopulation [panitumumab + Ch]). The baseline RAS mutational status concordance between tissue and liquid biopsies was 94.0% (93.2%, panitumumab + Ch). At 20 weeks, only one patient in the study (included in the panitumumab + Ch) had an emerging cfDNA RAS mutation. No emerging BRAF or EGFR mutations were reported. At disease progression, 6 patients had emergent mutations not present at baseline (RAS conversion rate: 13.3% [6/45]; 15.0% [6/40], panitumumab + Ch). CONCLUSIONS: The concordance rate between liquid and solid biopsies at baseline was very high, as previously reported, while our results suggest a considerable emergence of RAS mutations during disease progression. Thus, the dynamics of the genomic landscape in ctDNA may provide relevant information for the management of mCRC patients.

Efficacy and safety of chemotherapy in young patients with advanced gastroesophageal adenocarcinoma: data from the Spanish AGAMENON-SEOM registry.

BACKGROUND: Gastroesophageal adenocarcinoma in young adults (GCYA) counts for 10-15% of diagnoses. Previous studies have mainly focused on surgical outcomes in patients with resectable tumors; however, systemic therapy for advanced GCYA remains under-evaluated. This study aims to assess the efficacy-related outcomes and safety of first-line chemotherapy (CT) in younger versus older patients with advanced gastroesophageal adenocarcinoma. METHODS: Patients with advanced gastroesophageal adenocarcinoma from the AGAMENON-SEOM registry treated with first-line polychemotherapy between January 2008 and October 2022 were included. We compared clinicopathological features, therapies received, efficacy-related outcomes, and toxicity between individuals aged < and ≥ 45 years. RESULTS: Out of 3386 patients, 263 (7.8%) were < 45 years. Young patients exhibited a higher proportion of females affected, lower ECOG-PS ≥ 2, fewer comorbidities, and more aggressive disease-related features, such as higher proportion of diffuse subtype, signet-ring cells, plastic linitis, grade 3, peritoneal metastases and metastatic disease at diagnosis. They received more triple-agent combinations and underwent more surgeries in metastatic setting. No significant differences were observed between groups in overall response rate (53.1% vs. 52.3% in < and ≥ 45 years, respectively, p = 0.579), progression-free survival (6.1 vs. 6.83 months, p = 0.158) and overall survival (11.07 vs. 10.81 months, p = 0.82), even after adjusting for potential confounding factors. Grade 3-4 adverse events were comparable in both groups, although toxicity leading to treatment discontinuation was more frequent in older patients. CONCLUSIONS: In the AGAMENON-SEOM registry, younger patients with GCYA exhibited more aggressive clinicopathological features, and despite receiving more aggressive treatments, similar efficacy outcomes and toxicity profiles were achieved compared to their older counterparts. In the AGAMENON-SEOM registry, GEAC in < 45 years showed more aggressive clinicopathological features and, although treated with more intense first-line CT regimens, similar efficacy outcomes and toxicity were achieved compared to older patients.

Evolution of RAS Mutations in Cell-Free DNA of Patients with Tissue RAS Wild-Type Metastatic Colorectal Cancer Receiving First-Line Treatment: The PERSEIDA Study.

The serial analysis of cell-free DNA (cfDNA) enables minimally invasive monitoring of tumor evolution, providing continuous genetic information. PERSEIDA was an observational, prospective study assessing the cfDNA RAS (KRAS/NRAS) mutational status evolution in first-line, metastatic CRC, RAS wild-type (according to baseline tumor tissue biopsy) patients. Plasma samples were collected before first-line treatment, after 20 ± 2 weeks, and at disease progression. One hundred and nineteen patients were included (102 received panitumumab and chemotherapy as first-line treatment-panitumumab subpopulation). Fifteen (12.6%) patients presented baseline cfDNA RAS mutations (n = 14 [13.7%], panitumumab subpopulation) (mutant allele fraction ≥0.02 for all results). No patients presented emergent mutations (cfDNA RAS mutations not present at baseline) at 20 weeks. At disease progression, 11 patients (n = 9; panitumumab subpopulation) presented emergent mutations (RAS conversion rate: 19.0% [11/58]; 17.7% [9/51], panitumumab subpopulation). In contrast, three (5.2%) patients presenting baseline cfDNA RAS mutations were RAS wild-type at disease progression. No significant associations were observed between overall response rate or progression-free survival and cfDNA RAS mutational status in the total panitumumab subpopulation. Although, in patients with left-sided tumors, a significantly longer progression-free survival was observed in cfDNA RAS wild-type patients compared to those presenting cfDNA RAS mutations at any time. Continuous evaluation of RAS mutations may provide valuable insights on tumor molecular dynamics that can help clinical practice.