Genetic evolution to tyrosine kinase inhibitory therapy in patients with EGFR-mutated non-small-cell lung cancer.

BACKGROUND: Tumour heterogeneity impacts the efficacy of metastatic cancer treatment even if actionable mutations are identified. Clinicians need to understand if assessing one lesion provides reliable information to drive a therapeutic decision in non-small-cell lung cancer (NSCLC) patients. METHODS: We analysed inter-tumour heterogeneity from five autopsied individuals with NSCLC-harbouring mutations in the epidermal growth factor receptor (EGFR), treated with EGFR tyrosine kinase inhibitors (TKIs). Through a comprehensive next-generation sequencing (NGS) oncopanel, and an EGFR panel for digital droplet PCR (ddPCR), we compared metastases within individuals, longitudinal biopsies from the same lesions and, whenever possible, the primary naive tumour. RESULTS: Analysis of 22 necropsies from five patients revealed homogeneity in pathogenic mutations and TKI-resistance mechanisms within each patient in four of them. In-depth analysis by whole-exome sequencing from patient 1 confirmed homogeneity in clonal mutations, but heterogeneity in passenger subclonal alterations. Different resistance mechanisms were detected depending on the patient and line of treatment. Three patients treated with a c-MET inhibitor in combination with TKI lost MET amplification upon progression. CONCLUSION: At a given point and under selective TKI pressure, a single metastasis biopsy in disseminated tumours from EGFR-mutated NSCLC patients could provide a reasonable assessment of actionable alterations useful for therapeutic decisions.

How I treat gastric adenocarcinoma.

Gastric and gastro-oesophageal junction cancer (GC) represents a worldwide problem, this being the fifth most common malignancy. The fragility of patients with GC together with the aggressiveness of this tumour makes it as one of the most difficult neoplasias to manage. This article summarises the main strategies for treating patients with GC. Correct assessment of patients with GC requires a multidisciplinary evaluation and close follow-up. For patients with resectable tumours, perioperative chemotherapy should be always considered, especially in the neoadjuvant setting given its capacity for tumour downstaging and eradication of micro-metastases. In the metastatic setting, first-line and second-line treatment improve survival and quality of life in patients with GC. In this setting, only trastuzumab as first-line therapy in patients with human epidermal growth factor receptor 2 positive tumours and ramucirumab as second-line therapy have demonstrated a clear survival improvement. The lack of adequate biomarker selection and the intrinsic heterogeneity of these tumours have jeopardised the possible usefulness of many other targeted agents. Finally, when considering GC carcinogenesis as a multiple stepwise process from initial inflammation starting in the gastric epithelia, immune checkpoint inhibitors may improve the survival of these patients, although the optimal setting for their activity has yet to be fully elucidated.