The complexities of lymphoma: The importance of subtypes
Lymphoma is one of the most prevalent forms of blood cancer, which itself represents the fourth most common cause of cancer death worldwide.1 Each year, it is estimated that more than 500,000 people are diagnosed with lymphoma,1 yet this complex group of diseases has a relatively limited understanding among the general public.
In fact, findings from a survey last year showed a widespread lack of awareness: a third (32%) of respondents were unable to identify lymphoma as a type of cancer and only 21% were aware of non-Hodgkin lymphoma (NHL), which is the most common type within this group of diseases.
Since its first formal description almost two centuries ago,2 significant advancements have been made in the way we understand, diagnose and ultimately treat lymphomas.
A crucial step in this progress came with the discovery that lymphomas actually comprise a diverse group of diseases, which differ according to their biology as well as their clinical presentation and prognosis. First differentiating Hodgkin versus non-Hodgkin lymphomas, doctors and researchers later went on to classify aggressive (fast-growing) and indolent (slow growing) lymphomas, and further identify more than 90 various subtypes of NHL.3
With fundamental differences between the subtypes, it might be helpful to draw an analogy to the fruits that make up the citrus family. Although each fruit is part of the same family they are different in size, appearance and taste. Similarly, NHL subtypes form a type of disparate family but they differ biologically and clinically, meaning they have widely different prognoses and treatment strategies.
“Over the course of my career, I have witnessed first-hand many of the ground-breaking advances in our understanding of how lymphoma subtypes behave, and the need to treat them differently,” said Sandra Horning M.D., Chief Medical Officer and Head of Global Product Development at Roche, and a former practising haematologist and clinical investigator. “There is no one-size-fits-all approach. Ensuring a patient receives the correct diagnosis of their subtype is paramount to the overall management of their disease.”
Different subtype, different treatment goal
Alongside greater understanding of subtypes at a molecular level, scientific advances in treatment have made a huge difference to the lymphoma landscape. Innovative research has led to the development and availability of targeted therapies. As a result of these advances, survival rates have improved since the late 1990s, with mortality rates decreasing by 2.4% per year from 2006 to 2010.4
Broadly speaking, NHL is a disease in which white blood cells grow abnormally in the lymphoid organs (i.e. lymph nodes), ultimately affecting the immune system. Two main categories of the disease have been identified, and the approach to managing each of these varies.
For patients with follicular lymphoma – the most common type of indolent NHL – the main focus of treatment is to keep the disease under control while maintaining a good quality of life for patients. Although follicular lymphoma is generally considered incurable, patients who respond well to treatment can usually live in remission and without the need for further therapy for long periods of time.5 Continued research and innovation is improving treatment options for patients with this NHL subtype.
If we look at diffuse large B-cell lymphoma (DLBCL) – the most common form of aggressive NHL – curing the disease is the ultimate goal.6 However, DLBCL can return in as many as 40% of patients, at which point controlling the disease becomes the focus of treatment.7,8,9 Researchers and doctors alike continue to push boundaries in exploring new approaches for aggressive lymphomas like DLBCL.
“While significant progress has been made, it has not been equal across lymphomas, and certain subtypes remain more difficult to treat,” said Sandra Horning. “It’s essential that we progress research, with the ultimate goal of improving the lives of patients with all types of NHL.”
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- Globocan 2018. World Fact Sheet. [Internet; cited November 2018]. Available at: http://gco.iarc.fr/today/data/factsheets/populations/900-world-fact-sheets.pdf.
- Hodgkin T. On some morbid appearances of the absorbent glands and spleen. Med Chir Trans. 1832;17: 68-114.
- Lymphoma Research Foundation. About lymphoma. [Internet; cited November 2018]. Available at: http://www.lymphoma.org/site/pp.asp?c=bkLTKaOQLmK8E&b=6299689.
- American Cancer Society. Cancer Facts & Figures 2014. [Internet; cited November 2018]. Available at: http://www.cancer.org/acs/groups/content/@research/documents/webcontent/acspc-042151.pdf.
- Liu Q, et al. Improvement of overall and failure-free survival in stage IV follicular lymphoma: 25 years of treatment experience at The University of Texas M.D. Anderson Cancer Center. J Clin Oncol. 2006;24:1582-9.
- American Cancer Society. Types of non-Hodgkin lymphoma. [Internet; cited November 2018]. Available at: http://www.cancer.org/cancer/non-hodgkinlymphoma/detailedguide/non-hodgkin-lymphoma-types-of-non-hodgkin-lymphoma.
- Maurer MJ, et al. Event-free survival at 24 months is a robust end point for disease-related outcome in diffuse large B-cell lymphoma treated with immunochemotherapy. J Clin Oncol. 2014;32:1066-73.
- Coiffier B, et al. CHOP chemotherapy plus rituximab compared with CHOP alone in elderly patients with diffuse large-B-cell lymphoma. N Engl J Med. 2002;346:235-42.
- Coiffier B, et al. Long-term outcome of patients in the LHN-98.5 trial, the first randomized study comparing rituximab-CHOP to standard CHOP chemotherapy in DLBCL patients: a study by the Groupe d’Études des Lymphomes de l’Adulte. Blood 2010;116:2040-5.