PET/CT before autologous stem cell transplantation predicts outcome in refractory/relapsed follicular lymphoma

Salvage of young patients with follicular lymphoma (FL) after R-CHOP includes salvage immunochemotherapy followed by autologous stem cell transplantation (ASCT). Previous studies dealing with relapsed Hodgkin lymphoma have shown the prognostic value of PET/CT prior to ASCT.

We retrospectively analysed 59 patients with refractory/relapsed FL after first-line R-CHOP who were chemosensitive (as evaluated by CT) to the salvage treatment and who proceeded to ASCT. The role of PET/CT in this setting to define chemosensitivity is not definitely established. So we focused on the prognostic value of PET/CT performed after salvage treatment, before ASCT.

The estimated 3-year progression-free survival (PFS) and overall survival were 63.1 % (50.9–78.3 %) and 90.5 % (82.8 – 98.8 %), respectively, and did not differ significantly according to their Follicular Lymphoma International Prognostic Index at relapse, conditioning regimen, or type of salvage. PFS was significantly lower in PET/CT-positive patients, according to the International Harmonization Project revised response criteria, with a 3-year PFS of 45.5 % (26.6 – 77.8 %) versus 72.6 % (58.5 – 90.0 %; p = 0.039). To better refine prognosis, we applied two types of throsholds: a Deauville five-point scale positive threshold of ≥3 (3-year PFS of 74.9 %, range 61.0 – 92.1 % %, versus 42.8 %, range 24.7 – 74.4 %; p = 0.02), and a ≥70 % ∆SUV_max threshold between presalvage and pre-ASCT PET/CT (3-year PFS of 72.4 %, range 57.5 – 91.3 % versus 13.3 %, 2.2 – 81.7 %; p < 10⁻³). The PET/CT findings before ASCT were independently correlated with PFS in our series.

PET/CT negativity before ASCT is a desirable and achievable goal in the management of chemosensitive FL relapsing after first-line R-CHOP.