ORIGINAL ARTICLE Staging, Response to Therapy, and Restaging of Lymphomas with 18 F-FDG PET Javier Altamirano, a,b,c Jorge Reyes Esparza, c Jaime de la Garza Salazar, a Pedro Sobrevilla Calvo, a Silvia Rivas Vera, a Juan Ramo ´n Chalapud Revelo, a and Gisela Estrada b,c a Instituto Nacional de Cancerologı ´a, Me ´xico, D.F., Me ´xico b Unidad PET-Cyclotron, Universidad Nacional Auto ´noma de Me ´xico, Me ´xico, D.F., Me ´xico c Escuela de Farmacia, Universidad de Morelos, Cuernavaca, Me ´xico Received for publication February 9, 2007; accepted July 9, 2007 (ARCMED-D-07-00060). Background. We undertook this study to determine the diagnostic accuracy of 18 FDG af- ter three cycles and at the end of chemotherapy in non-Hodgkin’s lymphoma (NHL) or Hodgkin’s lymphoma (HL). We also evaluated the role of 67 Ga, bone marrow aspiration (BMA), and computed tomography (CT) in monitoring lymphoma treatment. Methods. 18 FDG, 67 Ga, BMA, and CT were performed before chemotherapy on 40 un- treated patients. 18 FDG and CT data were also obtained in 28/40 patients after 3 cycles of chemotherapy and at the end of chemotherapy. Patients had a median follow-up of 18 months, 21 had NHL, 7 had HL. Age range was from 15 to 74 years. Histopathology con- sidered the standard reference at the initial stage. Follow-up was a comparative study of all exam results. Results. Initial staging for PET and CT was as follows: sensitivity (Se) was 100%, spec- ificity (Sp) 100%, positive predictive value (PPV) 100%, negative predictive value (NPV) 0%, and accuracy (Ac) 100%. 67 Ga was Se, 64%; Sp, 0%, PPV, 100 %; and Ac, 64%. After the third cycle of chemotherapy and at the end of chemotherapy, Se, Sp, PPV, NPV, and Ac were always higher with PET than with CT. Eighteen patients had complete response, and seven had partial or no response. Conclusions. 18 FDG had greater prognostic values than CT after the third and last cycle of chemotherapy. PET after three cycles of chemotherapy is predictive of 18-month out- come in patients with intermediate and aggressive NHL and HL and may help in the iden- tification of patients who would benefit from more intensive treatment or from a change in chemotherapy. Ó 2008 IMSS. Published by Elsevier Inc. Key Words: 18 FDG PET, Lymphoma, Staging, Response to therapy, Progression-free survival. Introduction Positron emission tomography with 2-D-18-fluoro-2-deoxy- glucose ( 18 F-FDG PET) has established itself as an imag- ing tool for initial staging and evaluation of treatment response, as well as a prognostic indicator of Hodgkin’s lymphoma (HL) and non-Hodgkin’s lymphoma (NHL) (1,2), with high sensitivity and specificity (3). The 18 F- FDG PET is currently available in Mexico as a whole body diagnostic modality for the study of patients with lymphoma. 18 F-FDG has been shown to be a useful tool for imaging HL and NHL. There is enough evidence re- garding the relationship between tracer uptake and the proliferative activity in malignant lymphoma (4,5), al- though some authors point to a controversy in the correla- tion between tumor grade and 18 F-FDG standard uptake value (SUV) because there are some overlapping values between high- and low-grade lymphomas (6,7). It has also Published previously online October 8, 2007. Address reprint requests to: Javier Altamirano, Hospital A ´ ngeles de las Lomas, Vialidad de la Barranca s/n, col. Valle de las Palmas, 52763, Huixquilucan, Edo. de Me ´xico, Me ´xico; E-mail: draltaley@yahoo.com 0188-4409/08 $esee front matter. Copyright Ó 2008 IMSS. Published by Elsevier Inc. doi: 10.1016/j.arcmed.2007.07.003 Archives of Medical Research 39 (2008) 69e77