Real-life targeted next-generation sequencing for lymphoma diagnosis over 1 year from the French Lymphoma Network

As the impact of targeted next-generation sequencing (TNGS) on daily diagnosis has not been evaluated, we performed TNGS (46 genes) on lymphomas of unclear subtype following expert haematopathological review. The potential impact on patient care and modifications of final diagnosis were divided into major and minor changes according to the European Society of Medical Oncology (ESMO) guidelines. Among 229 patients [19 primary central nervous system lymphomas (PCNSL), 48 large B-cell lymphomas (LBCLs), 89 small BCLs (SBCLs), seven Hodgkin lymphomas (HL), 66 T-cell lymphomas], the overall concordance rate of histological and TNGS diagnosis was 89 center dot 5%. TNGS confirmed the histological diagnosis in 144 cases (62 center dot 9%), changed the diagnosis in 24 cases (10 center dot 5%) and did not help to clarify diagnosis in 61 cases (26 center dot 7%). Modifications to the final diagnosis had a clinical impact on patient care in 8 center dot 3% of cases. Diagnostic modifications occurred in all types of lymphoma except in PCNSL and HL; the modification rate was 14 center dot 6% in SBCL and 12 center dot 5% in LBCL. While comparing informative and uninformative cases, no differences were found in terms of DNA amplification, quality or depth of sequencing and biopsy type. The present study highlights that TNGS may directly contribute to a more accurate diagnosis in difficult-to-diagnose lymphomas, thus improving the clinical management in routine practice.