In a breakthrough for early stage low-grade lymphoma, set to change the management of the disease worldwide, an international clinical trial has found that patients live longer without a relapse with immuno-chemotherapy plus radiotherapy treatment rather than radiotherapy alone.
The results of the international phase III TROG 99.03 clinical trial will be presented today during a Plenary Session at the 2016 American Society for Radiation Oncology (ASTRO) Annual Meeting in Boston, US.
The primary aim of the trial was to see if, by adding immuno-chemotherapy to the standard treatment of radiotherapy alone, outcomes could be improved for patients with stage I-II low-grade follicular lymphoma. Patients were randomised to one of two arms; radiotherapy alone or radiotherapy followed by six cycles of Cyclophosphamide, Vincristine, Prednisolone (CVP) or in the later part of the trial, Rituximab and CVP (R-CVP).
Australian Trial Co-Chair and Peter MacCallum Cancer Centre Radiation Oncologist, Professor Michael MacManus, said that the multi-centre international study, which accrued 150 participants across Australia, New Zealand and Canada, was the first of its kind to be conducted and will help define the standard of care for these patients.
“The role of effective additional multi-agent drug or ‘systemic’ therapy combined with radiotherapy has never been effectively studied before, despite the pressing need for a study like this,” Professor MacManus said.
“This is a slow-growing lymphoma and in the short term, the prognosis is good. Radiotherapy can cure around half of these patients. However, more than half of the patients will eventually relapse after radiotherapy alone, generally outside the area of the body treated with radiotherapy. Although the disease may then respond well to further therapy, most patients will eventually die from lymphoma after their relapses.
“It is clear from the trial results that radiotherapy plus R-CVP, is associated with a much better chance that patients will survive to 10 years without a relapse. It is likely to mean that the cure rate will be much higher.
“No group anywhere in the world has ever managed to complete a trial comparing radiotherapy alone with radiotherapy and multi-agent chemotherapy or immuno-chemotherapy before. The long natural history of the disease makes it very difficult to perform randomised trials in these patients, because it takes many years to know if their treatment has been effective. Few trials groups can sustain a trial over the more than 15 years that would be required to answer the question. Our trial has run for 16 years.
“Overnight, this trial will transform our knowledge of the comparative effectiveness and toxicity of two very different treatment strategies for these patients. The results of this trial will immediately inform every discussion of treatment strategy for every patient with stage I-II follicular lymphoma in the developed world.”
The trial was a collaboration between TROG Cancer Research and the Australasian Leukaemia and Lymphoma Group.