In the above video a world-renowned CLL expert from MD Anderson Cancer Center, Dr. William Wierda, very briefly explains the difference between CLL (chronic lymphocytic leukaemia) and SLL (small lymphocytic lymphoma).
What is chronic lymphocytic leukaemia (CLL)?
CLL is a malignancy of B lymphocytes, one of several types of cells of the immune system. Disorders of the other lymphocytes also occur – T cells and natural killer (NK) cells – but are much rarer. While CLL is the commonest adult leukaemia in the western world, there are many other types of malignancy of B lymphocytes, globally referred to as B-cell lymphoproliferative disorders (B-LPD).
As suggested by the term ‘leukaemia’, CLL is a disease characterised by an increase in the abnormal B-cells in the blood and bone marrow (BM). Rarely, CLL cells may not be detected in the blood (or BM), but only found in enlarged glands – lymph nodes (see below) – which is a form of CLL localised to the tissues and often referred to as small lymphocytic lymphoma (SLL). SLL is a subset of CLL and should be treated as any other case of CLL.
Despite CLL being termed a ‘leukaemia’, the most recent classification by the World Health Organisation (WHO) is as an indolent low grade lymphoma. The dominating feature of CLL is an increase in B lymphocytes in the blood – a ‘lymphocytosis’, however, infections may also lead to a lymphocytosis, usually of T or NK-cells, but also of B-cells. Most commonly, viral infections – which may or may not cause clinical symptoms – are the cause of a lymphocytosis, which resolves spontaneously with time.
Originally CLL was considered a disease of the elderly with limited chance of a successful remission following treatment. Whilst the median age at diagnosis is 71 years, more recently a new entity termed CLL-type Monoclonal B-cell lymphocytosis (MBL), in which cells biologically appear to be the same as in CLL, but with a far few number of cells in the blood (less than 5000 cells per microliter). For these patients active monitoring is recommended by means of a full blood count and physical examination by the consultant haematologist. In cases referred for subsequent investigation of a lymphocytosis, the risk of requiring treatment for progressive disease in approximately 1% per year.
In this webcast video with slides prepared from the Cambridge 2014 CLLSA meeting Consultant Dr George Follows of Cambridge University hospitals gives a great talk delivered in way to help you navigate and understand some of the complexities of CLL/SLL from diagnosis to treatment. This is a great overview in very patient/carer friendly language and provides you a good foundation and summary of where we are today in the UK to aid you to live well with CLL/SLL.
What is Small Lymphocytic Lymphoma (SLL)?
CLL is typically diagnosed following a routine blood test showing a high peripheral blood lymphocyte count. If one biopsies the lymph nodes of CLL patients who present with enlarged lymph nodes you find exactly the same CLL cells in the lymph node as the blood. The term lymphoma is used for patients who have normal lymphocyte counts but who come to medical attention either because of B symptoms or because of lymph nodes, liver or spleen enlargement. On biopsy around 10% of patients who present with suspected lymphoma have lymph nodes contain CLL cells just like a lymph node biopsy from a CLL patient. However, they can’t be called leukaemia simply because they do not have a raised blood lymphocyte count!!! So SLL patients – like MBL patients- have a normal peripheral blood lymphocyte count but unlike MBL patients have clinical symptoms and/or clinical organ involvement such as enlarged lymph nodes, spleen, liver or bone marrow infiltration. SLL is about 10% as common as CLL but should be managed in exactly the same way as they are effectively the same disease but for reasons which are not fully explained the CLL cells in the lymph nodes, liver, spleen or bone marrow of SLL patients do not circulate in the peripheral blood.
Role of the Nurse Specialist
In this webcast video with slides; Gwyn Stafford Nurse Specialist at Cambridge University Teaching Hospitals discusses the role of the Nurse Specialist outlining some of the practical issues and what support is available to patients and their families during your care. Visits to the consultant for monitoring and guidance may be infrequent; the Nurse Specialist is likely to be your key point of contact with your clinical care team.
2014 UK patient information booklet: Bloodwise formerly Leukaemia & Lymphoma Research (LLR)
The above booklets are good introduction overviews to CLL and are written in understandable language to help UK patients and carers understand CLL , clinical care, treatment and access to support resources.