The Czech Lymphoma Study Group (CLSG) is a professional association of physicians and other healthcare and non-healthcare providers in the Czech Republic specializing in the diagnosis, treatment, and research of malignant lymphomas.

The main objectives of CLSG are:

1. Development of diagnostic and treatment protocols. CLSG’s primary goal is to harmonize treatment approaches across centers and ensure that the latest clinical research findings are translated into routine practice. It issues expert recommendations that contribute to the standardization of care for patients with lymphomas. Current diagnostic and therapeutic guidelines are available on this website.
2. Development and organization of clinical studies. CLSG actively participates in the design and conduct of multicenter clinical trials. Information on ongoing and accruing trials at CLSG centers is regularly updated and accessible on our website.
3. Analyses and presentation of lymphoma treatment results. Treatment results are monitored through analyses of data from the NiHiL registry. Findings are published in peer‑reviewed international journals and presented at major international conferences (see details here).
4. Education in the field of lymphomas. The CLSG group organizes professional conferences and is actively engaged in the education of young physicians and other specialists in hematologic oncology.
5. Support for lymphoma research. CLSG fosters research initiatives that advance knowledge and innovation in the field.

Through its long-standing activities, CLSG represents a key platform for sharing experience, unifying treatment standards, and supporting research in lymphoproliferative diseases in the Czech Republic. Its work significantly contributes to improving the quality of patient care and strengthening international collaboration within the Czech hematology community.

The Czech national non-Hodgkin lymphoma (NHL) registry “NiHiL” (registered in ClinicalTrials.gov under NCT03199066) was established in 1999 by the Czech Lymphoma Study Group to monitor epidemiological data, treatment modalities, and outcomes of NHL patients in real-world clinical practice. From its beginning through mid-2025, the registry has collected data on more than 25,000 unique NHL cases, making it one of the largest national lymphoma registries.

In recent years, approximately 70% of all NHL patients in the Czech Republic treated at one of the eight university hospital–based centers of intensive hematology care for adults or collaborating regional hospitals have been included. NiHiL has significantly contributed to numerous clinical and translational research studies that have shaped current understanding of lymphoma epidemiology, risk stratification, and therapeutic outcomes (for details see "Publications"). These outputs highlight the registry’s importance not only as a tool for benchmarking of clinical practice, but also as a robust scientific resource for advancing lymphoma research internationally.

Centers of intensive hematology care in the Czech Republic by annual contribution to the NiHiL registry.