Radiation Dose Optimization in Diffuse Large B- Cell Lymphoma.

The purpose of this study is to compare standard dose radiation of 45 Gray(Gy) in 25 fractions in Non Hodgkin's Lymphoma- Diffuse Large B cell Lymphoma (NHL-DLBCL) to that of 36 Gy in 20 fractions. The role of radiation in NHL-DLBCL has been addressed in large cooperative trials showing improvement in overall survival and progression free survival with combined modality treatment. The doses of radiation used in these trials are heterogeneous ranging from 30-55 Gray(Gy). There is uncertainty about the optimal dose of radiation needed in aggressive lymphomas. A dose response phenomenon is known in Non- Hodgkin's Lymphoma. Late effects of higher dose radiation in the form of higher risk of stroke, myocardial infarction, thyroid abnormalities and secondary breast cancer are being increasingly identified. Hence it is essential to optimize the dose of radiotherapy for lower toxicity without compromising on efficacy.