This multicentre, prospective, randomised-controlled trial compared efficacy and toxicity of differing radiotherapy doses in non-Hodgkin lymphoma (NHL).

Patients with any histological subtype of NHL, requiring radiotherapy for local disease control, whether radical, consolidative or palliative, were included. Three hundred and sixty one sites of indolent NHL (predominantly follicular NHL and marginal zone lymphoma) were randomised to receive 40-45Gy in 20-23 fractions or 24Gy in 12 fractions. Six hundred and forty sites of aggressive NHL (predominantly diffuse large B cell lymphoma as part of combined-modality therapy) were randomised to receive 40-45Gy in 20-23 fractions or 30Gy in 15 fractions. Patients with all stages of disease, having first-line and subsequent therapies were included; first presentations of early-stage disease predominated.

There was no difference in overall response rate (ORR) between standard and lower-dose arms. In the indolent group, ORR was 93% and 92%, respectively, (p=0.72); in the aggressive group, ORR was 91% in both arms (p=0.87). With a median follow-up of 5.6years, there was no significant difference detected in the rate of within-radiation field progression (HR=1.09, 95%CI=0.76-1.56, p=0.64 in the indolent group; HR=0.98, 95%CI=0.68-1.4, p=0.89 in the aggressive group). There was also no significant difference detected in the progression free or overall survival. There was a trend for reduced toxicities in the low-dose arms; only the reduction in reported erythema reached significance.

In a large, randomised trial, there was no loss of efficacy associated with radiotherapy doses of 24Gy in indolent NHL and 30Gy in aggressive NHL, compared with previous standard doses of 40-45Gy.