Lymphoma is a type of cancer that affects the immune system. It develops when the white blood cells or lymphocytes, the blood cells produced by bone marrow and which defend the body from infections, lose control and divide abnormally or do not die when they should.
White blood cells usually circulate around the entire body via the lymph system, which forms part of the immune system, and they can be found in the blood, the spleen, tonsils, lymph nodes, adenoids (masses of lymphatic tissue located precisely where the nose joins the mouth) and lymph itself.
Healthy lymphocytes tend to accumulate in the lymph nodes (primarily in underarm, groin and neck areas) as they find this to be the best place to fight off infections. In people with lymphoma, the diseased lymphocytes form excessive accumulations in the lymph nodes, although they can also accumulate in other parts of the lymph system, such as the spleen, or even in other areas outside the system (lungs, liver, etc.).
In Spain, approximately 10 new cases of lymphoma per 100,000 inhabitants are diagnosed every year; this level of incidence is practically identical to the European average (9.8 cases per 100,000 inhabitants per year). The condition is slightly more common in men (60% of all cases diagnosed in Spain) than women (40%).
However, there is also a special subtype of lymphoma with a lower incidence (2.4 new cases per 100,000 inhabitants per year) called Hodgkin’s lymphoma.
In either case, they are uncommon diseases compared to the cancers that most typically affect our society, such as breast cancer in women (with 85 new cases per 100,000 inhabitants annually) and prostate cancer in men (with 97 new cases per 100,000 inhabitants each year).