title: Use of subsequent PET/CT in diffuse large B-cell lymphoma patients in complete remission following primary therapy.
abstract: Interim 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (I-PET/CT) is a powerful tool for monitoring the response to therapy in diffuse large B-cell lymphoma (DLBCL). This retrospective study aimed to determine when and how to use I-PET/CT in DLBCL. A total of 197 patients treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) were enrolled between October 2005 and July 2011; PET/CT was performed at the time of diagnosis (PET/CT0), after 2 and 4 cycles of chemotherapy (PET/CT2 and PET/CT4, respectively), and at the end of treatment (F-PET/CT). According to the International Harmonization Project for Response Criteria in Lymphoma, 110 patients had negative PET/CT2 scans, and 87 had positive PET/CT2 scans. The PET/CT2-negative patients had significantly higher 3-year progression-free survival rate (75.8% vs. 38.2%) and 3-year overall survival rate (93.5% vs. 55.6%) than PET/CT2-positive patients. All PET/CT2-negative patients remained negative at PET/CT4, but 3 were positive at F-PET/CT. Among the 87 PET/CT2-positive patients, 57 remained positive at F-PET/CT, and 32 progressed during chemotherapy (15 at PET/CT4 and 17 at F-PET/CT). Comparing PET/CT4 with PET/CT0, 7 patients exhibited progression, and 8 achieved partial remission. Comparing F-PET/CT with PET/CT0, 10 patients exhibited progression, and 7 achieved partial remission. In conclusion, our results indicate that I-PET/CT should be performed after 2 rather than 4 cycles of immunochemotherapy in DLBCL patients. There is a limited role for subsequent PET/CT in the detection of relapse in PET/CT2-negative patients, but repeat PET/CT is required if the PET/CT2 findings are positive.
authors.affiliation: Collaborative Innovation Center for Cancer Medicine, State Key Laboratory of Oncology in South China, Guangzhou, Guangdong 510060, P. R. China; Department of Nuclear Medicine, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong 510060, P. R. China.fanwei@sysucc.org.cn.
authors.forename: Xu
authors.initials: X
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Fan
authors.forename: Zhong-Jun
authors.initials: ZJ
authors.lastname: Xia
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Hu
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: Lin
authors.forename: Ya-Rui
authors.initials: YR
authors.lastname: Zhang
authors.forename: Zhi-Ming
authors.initials: ZM
authors.lastname: Li
authors.forename: Pei-Yan
authors.initials: PY
authors.lastname: Liang
authors.forename: Yuan-Hua
authors.initials: YH
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D016403:Lymphoma, Large B-Cell, Diffuse / Q000175:diagnosis / Q000188:drug therapy* / Q000401:mortality; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D012074:Remission Induction; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult