A new Oncology article, with first author Chris Kelsey of Duke University, reviews existing findings about the use of radiation treatment in patients with diffuse large B-cell lymphoma (DLBCL). Their take: radiation treatment is a useful consolidation treatment, meaning a short-term method for improving the results of the main treatment. (Contrast this with a maintenance therapy, which is a long-term method of accomplishing the same task; the classic example is the 2-year rituximab maintenance cycle).
This is bound to be a controversial study, given that there's still debate around the subject. Oncology knows it, too: they took the liberty of having a response prepared by Philip J. Bierman from Nebraska. Lymphoma patients should be aware of both perspectives. This is just another example of how the treatment of this cancer remains uncertain, where oncologists differ and have valid, if competing, reasons to do so. Never, ever, attempt to make a decision about your own life on the basis of a single study or even, unless you really have reason to trust it, a single opinion.
DLBCL is the most common type of non-Hodgkin's lymphoma, and the most common aggressive form of the disease. People with certain indolent diseases, like follicular lymphoma, are also at heightened risk of having their disease transform into DLBCL as it progresses. Although fast-growing, it often responds well to chemotherapy, usually R-CHOP, and the 5-year survival rate is at least 60%.
Kelsey's article begins from the premise that, while chemotherapy can be highly effective, relapses are also common, and when they happen, they usually happen at one of the sites where the disease was first identified -- not, for example, an entirely new and previously healthy region of the body. That observation leads to the hypothesis that some undetected tumour cells survive at those sites, and that they can be killed off through supplementary (i.e. consolidation) radiation treatment.
This article is a review, not a clinical study, which means Kelsey is presenting and comparing results from another studies rather than conducting his own primary research. For early-disease (Stage I and Stage II) patients, two studies showed a significant long-term survival advantage with radiation treatment (ECOG 1484, IELSG 4) and three didn't (GELA LNH 93-4, GELA 93-1, SWOG 8736). All these patients were treated with CHOP only, meaning these patients did not benefit from rituximab (e.g. through R-CHOP).
For advanced disease, Kelsey finds, similarly, in favour of radiation treatment. There are less studies to go on here, but the authors argue that radiation treatment can have moderate benefits for people with a partial response to chemotherapy, as part of a stem-cell transplant regimen (they're on firmest and best-established ground here), and even for palliative care.
Be aware that this is not the whole story, however. The response comes from Philip Bierman and Charles Enke -- respectively, an internist and a radiation oncologist. Their principal objection, although they do not frame it this way, is that the Kelsey study fails to properly consider how effective chemotherapy has become in the age of rituximab. People without advanced disease and without an IPI risk factor (e.g. age, LDH) already have an impressive 3-year survival rate approaching 100% when treated with R-CHOP. They suggest that radiation treatment be reserved only for people who fail to fully respond to chemoimmunotherapy, since it does not seem to provide much additional benefit.
Ultimately, it's up to the individual, I suppose, to decide just how much punishment their body should take.
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