Picking petals.

PET-adaptive therapy has made its way to primetime for Hodgkin lymphoma (HL), usually after two cycles of ABVD. Now we have the first PET-adaptive trial for non-Hodgkin lymphoma (NHL). In the PETAL trial, 862 patients with aggressive NHL (mostly DLBCL) received R-CHOP x 2 then a PET. As opposed to the Deauville criteria used in HL, a “positive” PET scan was defined as a ≤66% decrease in max SUV. All PET(-) patients went on to complete additional R-CHOP x 4, while two intensified arms were tested for the 12.5% of patients with PET(+) disease: R-CHOP x 6 versus an even more intensive Burkitt-like regimen. The Burkitt regimen was not only more toxic, but also less effective. More importantly, PET(+) patients tended to relapse quickly after either chemo regimen, prompting an editorial to call for completely novel treatment options for chemo-refractory disease. Maybe, just maybe, we’ll get so novel as to one day circle back to none other than therapeutic photons as a component of therapy. TBL: An early PET-adaptive approach for aggressive NHL makes sense given its effectiveness at early prognostication...all we’re missing is an effective adaptive treatment strategy. | Duhrsen, J Clin Oncol 2018