Lymphomas and Total-Body Irradiation

Lymphomas originate from immune system cells in various stages of differentiation. They cause several morphological, immunological, and clinical situations according to their origins. Hodgkin’s lymphoma (HL) is histologically characterized by the presence of various numbers of diagnostic multinucleated giant cells (Reed-Sternberg cells) within a mixed inflammatory infiltrate and originates from the lymphoid system. HL constitutes 10% of all lymphomas and 1% of all malignancies. HL has childhood and young adult forms. Childhood form is seen in children <15 years and is associated with male predominance, increasing family size, low economic status, and mixed cellular subtype, whereas young adult form is observed in those aged 15–34 and is associated with high socioeconomic status and nodular sclerosing subtype. Non-Hodgkin’s lymphomas (NHLs) are malignancies of lymphoid-reticular system as monoclonal expansion of malignant T or B cells lacking the pathologic characteristics of Hodgkin’s lymphoma’s Reed-Sternberg cells. They are usually observed in older patients and show more extranodal involvement than HLs. They also do not show contagious LN extension patterns, and NHL prognosis is more strongly affected by histologic subtype along with age, disease extent, and treatment. Although the etiology of NHLs is uncertain, infectious agents including Epstein-Barr virus (EBV), human T-lymphotropic virus-1 (HTLV-1), Helicobacter pylori, and immunosuppression are contributory in the etiology of NHLs. Human biologic response to ionizing radiation and total-body irradiation (TBI) was of great military interest in the early 1940s prompting an initiative in developing nuclear weapons and researching human tolerance for radiation exposure along with advanced cancer and benign disease treatments. Hematopoietic stem cell transplantation is used in both restoration of normal hematopoiesis and treating cancer. TBI is used as a conditioning regimen prior to stem cell transplantation for bone marrow ablation, immune system suppression, and eradication of genetically damaged cells to accomplish a successful bone marrow transplant. Basic concepts that are crucial to understanding Hodgkin’s lymphoma, non-Hodgkin’s lymphoma, and total-body irradiation are reviewed in depth in this chapter.