Report on the Second International Workshop on interim positron emission tomography in lymphoma held in Menton, France, 8-9 April 2010.

One hundred and fifty hemato-oncologists and nuclear medicine specialists from more than 20 countries joined in April 2010 the 2-day Second International Workshop on interim PET in lymphoma. During the nuclear medicine session the advantages of the five-point scale Deauville criteria for interim PET reporting over the other sets of visual criteria were presented. The specific problems of PET reporting in escalation/de-escalation trials in Hodgkin lymphoma (HL) were addressed as well as the limitations of visual analysis for early PET evaluation in non-Hodgkin lymphoma (NHL). The applicability, efficacy, and reproducibility of quantitative criteria (ΔSUV(max) analysis and tumor/liver SUV ratio) for interim PET in NHL were reported. In retrospective and prospective series. Some of the interim PET-based clinical trials ongoing worldwide in HL and NHL were reported. In early-stage HL, three trials aimed at determining the feasibility of omitting radiotherapy in interim PET negative patients, and in advanced-stage HL two PET-based ABVD escalation or BEACOPP de-escalation trials, in NHL two studies reported preliminary results of interim PET in follicular lymphoma, in DLBCL a round-table discussion pointed out the lack of definite criteria for interim PET, and a few observational studies in DLBCL reported the comparison of the various techniques of interim PET reporting (visual versus quantitative). The preliminary results of two international validation studies of the five-point scale criteria in HL and NHL launched in 2009 were reported. The presentations of the meeting are available on http://eitti.free.fr.