We have previously reported the outcome of patients with relapsed/refractory lymphomas who continued to have residual FDG avid PET (positive) lesions after salvage chemotherapy and prior to ASCT. This group of patients included those who had excellent anatomic response by size criteria, but continued to have persistent hypermetabolic FDG activity within the residual lesions. We found that PET positive patients have an extremely poor chance of durable remission after ASCT. In the PET negative group, the median PFS was 19 months with 54% of patients without progression at 12 months after ASCT. In the PET positive group, the median PFS was 5 months with only 7% of patients without progression at 12 months after ASCT. We concluded that, for patients with PET positive residual disease after salvage chemotherapy and prior to ASCT, novel therapeutic approaches and agents need to be investigated.