Prognostic value of <sup>18</sup>F-FDG positron emission tomography in the early evaluation of the efficiency of treatment in patients with non-Hodgkin lymphomas
Objective: to define the role of <sup>18</sup>F-FDG positron emission tomography (PET) performed after 2-3 chemotherapy cycles in the prediction of disease prognosis and to identify a group of patients requiring more intensive treatment. Material and methods. Seventy-one patients with non-Hodgkin lymphoma of different histological types were examined. PET was carried out at different stages of diagnosis and primary treatment in the patients. Results. The examinations made after 2-3 polychemotherapy (PCT) cycles indicated that 36 (50.7%) patients continued to have signs of metabolic activity of lymphoproliferative disease (a PET-positive group) and 35 (49.3%) patients were found to have no abnormal tracer accumulation foci (a PET-negative group). Twenty-nine (82.9%) patients from the PET-negative group con­tinued to remain in complete remission throughout the follow-up (the median follow-up was 405 days). At late stages, 6 (17.1%) patients were identified to have abnormal tracer hyperfixation foci that were indicative of disease recurrence. Only 8 patients from the PET-positive group were observed to show a complete metabolic response to treatment at the end of first-line PCT. The metabolic activity of the disease was maintained in the remaining patients. The results of PET conducted at the late stages of the fol­low-up indicated that metabolically active tumor foci continued to be visualized in 20 (55.6%) patients and further treatment resulted in complete remission in 16 (44.4%) patients. Conclusion. PET findings could pre­dict the further cour­se of the disease and differentiate more in­tensive treatment-re­quiring patients at the early stages of chemotherapy