NCCN Guidelines for Patients® | Diffuse Large B-cell Lymphoma

10 NCCN Guidelines for Patients ® : Diffuse Large B-cell Lymphoma, 2017 1 DLBCL basics Diagnosis Mutations Cells have a control center called the nucleus. The nucleus contains chromosomes, which are long strands of DNA ( d eoxyribo n ucleic a cid) tightly wrapped around proteins. See Figure 2 . Within DNA are coded instructions for building new cells and controlling how cells behave. These instructions are called genes. There can be abnormal changes in genes called mutations. Some types of mutations that are linked to cancer are present in all cells. Other mutations are present only in cancer cells. Mutations cause cancer cells to not behave like normal cells and, sometimes, to look very different from normal cells. Researchers are still trying to learn what causes genes to mutate and cause cancer. Cancer’s threat Cancer cells don’t behave like normal cells. First, the mutations cause cancer cells to grow more quickly and live longer than normal cells. Normal cells grow and then divide to form new cells when needed. They also die when old or damaged as shown in Figure 3 . In contrast, cancer cells make new cells that aren’t needed and don’t die quickly when old or damaged. Over time, the lymphoma cells may build up in tissues and may travel in blood or lymph to other sites. Without treatment, the cancer may cause organs not to work. Diagnosis DLBCL is often a fast-growing tumor. The tumor often occurs in lymph nodes within the neck, armpit, or groin area but may appear elsewhere. Other common sites are the stomach and gut. When your doctor suspects cancer, testing is needed. The tests that are needed to confirm (diagnose) DLBCL are described next. Biopsy The only way to know if you have cancer is to test tissue or fluid. A biopsy is a procedure that removes samples of fluid or tissue for testing. There are many types of biopsy. For DLBCL, an incisional or excisional biopsy is advised. An incisional biopsy removes only a part of the tumor through a cut made into your body. An excisional biopsy removes the whole tumor. The methods used to do either biopsy depend on where the tumor is in your body. FNA ( f ine- n eedle a spiration) and a core needle biopsy remove very small samples with a needle. Neither should be used alone to diagnose DLBCL. You may have cancer even if these biopsies find no cancer. Hematopathology review The biopsy samples will be sent to a special type of pathologist. A pathologist is a doctor who’s an expert in testing cells to find disease. For DLBCL, the pathologist should be a specialist in hematopathology. Hematopathologists spend all of their time looking at blood, bone marrow, and lymph nodes. They become very good with diagnosing blood cancers. The hematopathologist will first examine the samples using a microscope.