Impact of positron emission tomography on primary staging and changing the therapeutic modality in lymphoma patients
Natalia B. Mikhaylova1, Marina S. Tlostanova2, Yulia N. Vinogradova2, Ekaterina I. Ivanova2, Anna V. Kritskaya2, Sergey E. Korolev1, Anna A. Rats1, Alexander A. Pugachev1, Nikolay V. Ilyin2, Boris V. Afanasyev1, Leonid A. Tyutin2
1Memorial R. M. Gorbacheva Institute of Children Hematology and Transplantation, St. Petersburg Pavlov State Medical University,
St. Petersburg, Russia; 2Russian Research Centre for Radiology and Surgical Technologies, St. Petersburg, Russia
We investigated the usefulness of FDG-PET in initial staging and its contribution in changing the therapeutic plan in lymphoma patients.
More than 200 PET scans were performed in 95 lymphoma patients (42-HL, 53-NHL) between 2004 and 2009. In 54 cases PET was performed at diagnosis and after completion of first-line therapy. In 41 patients the first PET study was done after first-line therapy or at the relapse of the disease. Patients with metabolic activity in nodes after first-line therapy received salvage therapy consisting either of conventional chemotherapy (CT) with PET positive node irradiation or high-dose CT with HSCT.
In 20% of NHL patients PET was the only method that revealed at least one pathological lesion not confirmed by computer tomography at diagnosis. In 71.2% of patients full metabolic response was achieved after first-line therapy; 27.8% of patients remained PET positive. Additional cycles of conventional CT and radiation converted PET-positivity to PET-negativity in 19.5% of cases, compared with 16% after ASCT. Early relapse was observed in 30% of patients with metabolic activity after first-line therapy compared with 20% in PET negative patients. Seventy-one percent of patients with PET-negative status did not relapse during the time of observation, whereas only 35% of patients with metabolic activity after first-line treatment remained in remission. The death rate was 23% in the PET-positive group, while no deaths were recorded in the PET-negative group. The overall survival rate was calculated in 41 patients and is represented in Fig. 1.
FDG-PET is useful at primary diagnosis. Approximately 20% of lymphoma patients could benefit from therapy changing initiated by PET status.
lymphomas, prognosis, positron emission tomography