Involved field radiation post autologous stem cell transplantation in lymphoma patients is associated with major haematological toxicities

Irradiation is known to cause temporary to permanent marrow aplasia in cancer patients when administered as a sole therapy or in combination with chemotherapy. Until now, no studies have been carried out evaluating the haematological toxicities of involved field radiation administered post autologous stem cell transplantation (ASCT). We assessed bone marrow (BM) toxicity in 93 patients who received involved field radiation post ASCT (non- Hodgkin's lymphoma 21, Hodgkin's disease 7, breast cancer 15, and other solid tumours 50. Severe BM toxicity, with grade IV neutropenia, and/or thrombocytopenia, and/or anaemia necessitating interruption of radiotherapy for more than a week, was observed in 11 patients (malignant lymphoma-8 of which 7 were NHL, and 1 HD, breast cancer-1, Wilm's tumour-1, Ewing's sarcoma-1). Patients with malignant lymphoma were at higher risk of developing post ASCT radiation-induced cytopenias than patients with breast cancer or solid tumours, 28% vs 4.5%, respectively (P < 0.05). Of the 11 patients, 7 developed bacterial sepsis and 10 were hospitalised. The radiation-induced cytopenia patients necessitated platelets and red blood cell transfusions, interrupting the course of irradiation. Of the patients suffering from non-Hodgkin's lymphoma, 8/14 (57%) of those who received conventional courses of radiotherapy relapsed compared to 6/7 (86%) of those who received interrupted radiotherapy (P < 0.05). The most appropriate timing for radiation in malignant lymphoma patients who are scheduled for ASCT, as well as the protective role of haematopoietic growth factors like erythropoietin and Granulocyte (G) of Granulocyte-Monocyte (GM), colony stimulating factors (CSF) and others, are discussed.