NCCN Guidelines for Patients® | Chronic Lymphocytic Leukemia

9 NCCN Guidelines for Patients ® : Chronic Lymphocytic Leukemia, 2018 There are many lymphocytes in bone marrow, blood, and your lymphatic system. Your lymphatic system consists of fluid, called lymph, and a network of tissues. Lymph travels in lymph vessels and passes through lymph nodes, which filter out germs and waste. Other organs of the lymphatic system include your thymus, spleen, and tonsils. CLL basics Cancer is a disease of cells. Leukemias are cancers of white blood cells and start in bone marrow and blood. CLL ( c hronic l ymphocytic l eukemia) is one type of leukemia that starts in lymphocytes called B-cells. Since CLL is a cancer of blood cells, it can spread anywhere in the body that blood can go, including lymph nodes, bone marrow, and even solid organs. CLL cells are found mostly within blood, bone marrow, and lymph nodes. SLL ( s mall l ymphocytic l eukemia) is a cancer that also starts in B-cells but occurs mostly within the lymphatic system (lymph nodes). See Figure 2. CLL and SLL are thought to be the same cancer but differ in the fact that people with SLL do not have high numbers of white blood cells. Their treatment is very similar. The focus of this book is CLL. CLL occurs mostly in people who are middle aged or older. Figure 2 Lymph vessels and nodes Lymph nodes and vessels are found throughout the body. A lymph node is a small group of special disease-fighting cells. Lymph nodes are connected to each other by a network of small tubes called lymph vessels. Illustration Copyright © 2017 Nucleus Medical Media, All rights reserved. 1 Chronic lymphocytic leukemia CLL basics