Small Lymphocytic Lymphoma / Chronic Lymphocytic Leukemia

Small lymphocytic lymphoma (SLL), is almost identical to chronic lymphocytic leukemia (CLL) both morphologically and clinically. CLL A somewhat arbitrary distinction is drawn between them based on the relative degree of lymph node and lymphoid tissue involvement verses the numbers of cells primarily in the bone marrow and peripheral blood.

As a lymphoma, SLL accounts for about 4-5% of non-Hodgkin's lymphoma. As a leukemia, CLL accounts for about 30% of adult leukemias in Western countries. In SLL the patients are elderly (median age 60 years) and usually present with diffuse lymphadenopathy and some degree of marrow and peripheral blood involvement (Stage IV disease). Men appear to get the disease as equally as women.

This lymphoma is very indolent but relentless, with median survivals of almost a decade. Although the slowly proliferating cells are sensitive to chemotherapeutic agents, chemotherapy is almost never curative and relapse inevitably follows.

Most studies find no benefit in treating patients until they develop symptoms. Therapy tends to be low-intensity: single alkylator therapy such as chlorambucil or combination therapy with cyclophosphamide/vincristine/prednisone. A new and promising drug is fludarabine, but it has not been shown to prolong survival so far.

High dose chemotherapy with bone marrow or stem cell transplant has been used to treat a small number of people with SLL / CLL. As side effects can be severe, some type of transplant are not given to people over the age of 45-50 and others can be given to people up to 65 years old who are in otherwise good health. The intensity of the treatment increases the risks of serious side effects for people over this age.

About 30% of cases of SLL progress to a higher grade process such as prolymphocytic lymphoma or diffuse large cell lymphoma (Richter's syndrome). Over time, 10% to 20% of cases of small lymphocytic lymphoma progress to chronic lymphocytic leukemia.

Resources

The US National Cancer Institute

Non-Hodgkin's Lymphoma Home Page
Chronic Lymphocytic Leukemia Treatment

Small Lymphocytic Lymphoma information from Cancerbackup (UK)
Generic Definitions from the Lymphoma Research Foundation (US)
Information from Lymphomation.Org
Chronic Lymphocytic Leukemia Links from Grannybarb & Art's Leukemia Links (recommended)
Information from Hematopathology
Information from a pathology update in the Cancer Control Journal April 1996: Indolent Lymphomas
Information on SLL from The Doctors Doctor
US National Cancer Institute (links above)
Frontiers in Bioscience is a source of B-cell information.