RESUMEN
Detection of peritoneal dissemination (PD) in gastric cancer (GC) patients remains challenging. The feasibility of tumor-guided cell-free DNA (cfDNA) detection in prospectively collected peritoneal fluid (ascites and peritoneal lavage) was investigated and compared to conventional cytology in 28 patients. Besides conventional cytology, next generation sequencing was performed on primary tumor DNA and cell-free DNA from peritoneal fluid. Patients were retrospectively grouped into: a positive group (with PD) and a negative group (without PD). Detectable mutations were found in the primary tumor of 68% (n = 19). Sensitivity of PD detection by tumor-guided cfDNA analysis was 91%, compared to 64% by conventional cytology. Within the positive group (n = 11), tumor-guided cfDNA was detected in all patients with ascites samples (4/4, 100%) and in 86% (6/7) of the lavage samples, opposed to 4/4 (100%) patients with ascites and 43% (3/7) with lavage by conventional cytology. Within the negative group (n = 8), conventional cytology was negative for all samples. In two patients, tumor-guided cfDNA was detected in peritoneal lavage fluid. Interestingly, these 2 patients developed PD within 6 months, suggesting a prognostic value of tumor-guided cfDNA detection. This study showed that tumor-guided cfDNA detection in peritoneal fluids of GC patients is feasible and superior to conventional cytology in detecting PD.
Asunto(s)
Líquido Ascítico , Ácidos Nucleicos Libres de Células , Neoplasias Peritoneales , Neoplasias Gástricas , Humanos , Neoplasias Gástricas/genética , Neoplasias Gástricas/patología , Neoplasias Gástricas/diagnóstico , Neoplasias Peritoneales/secundario , Neoplasias Peritoneales/genética , Neoplasias Peritoneales/diagnóstico , Femenino , Líquido Ascítico/patología , Líquido Ascítico/metabolismo , Masculino , Persona de Mediana Edad , Anciano , Ácidos Nucleicos Libres de Células/genética , Estudios Retrospectivos , ADN Tumoral Circulante/genética , Adulto , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Biomarcadores de Tumor/genética , Ascitis/genética , Ascitis/patología , Ascitis/diagnóstico , Mutación , Anciano de 80 o más Años , Lavado Peritoneal , ADN de Neoplasias/genética , ADN de Neoplasias/análisisRESUMEN
BACKGROUND: Diagnosis and treatment of leptomeningeal metastases (LM) in epidermal growth factor receptor mutation positive (EGFRm+) NSCLC is challenging. We aimed to identify resistance mechanisms (RM) to osimertinib in cerebrospinal fluid (CSF) and plasma. METHODS: EGFRm+ patients with new or progressive LM during osimertinib were enrolled. NGS Ampliseq was performed on DNA isolated from CSF. Patients were prescribed osimertinib dose escalation (DE, 160mg QD) following lumbar puncture. Clinical and radiological response was evaluated four weeks after osimertinib DE. RESULTS: Twenty-eight patients were included. The driver mutation was identified in 93% of CSF samples (n=26). Seven (27%) harbored ≥1 RM. Twenty-five patients (89%) were prescribed osimertinib DE. Four weeks afterwards, symptoms improved in five patients, stabilized in nine and worsened in eleven patients. Twenty-one (84%) patients underwent MR imaging. Four showed radiological improvement, fourteen stabilization, and three worsening. CONCLUSIONS: In 27% of patients an RM was found in CSF ctDNA, none of which are targetable at time of writing, and clinical efficacy of osimertinib DE seems limited. There is much to gain in diagnostic as well as therapeutic strategies in EGFRm+ NSCLC LM.