title: The impact of R-VACOP-B and interim FDG-PET/CT on outcome in primary mediastinal large B cell lymphoma.
abstract: The choice of a rituximab-based regimen and the prognostic significance of interim 2-[fluorine-18]fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography (FDG-PET/CT) in primary mediastinal large B cell lymphoma (PMBCL) are debatable. We evaluated the clinical features and outcomes of 95 consecutive patients with PMBCL who were treated between 1985 and 2009. Forty-three patients received rituximab-based chemotherapy, R-VACOP-B (N = 30) or R-CHOP21 (N = 13), whereas 52 patients were treated with VACOP-B (N = 47) or CHOP21 (N = 5). Radiotherapy was not given. Patients who received rituximab had a 5-year progression-free survival (PFS) of 79 % and overall survival (OS) of 97 % compared with 58 % (p = 0.06) and 88 % (p = 0.2), respectively, without rituximab. Five-year PFS in patients treated with R-VACOP-B, R-CHOP21, VACOP-B, and CHOP21 were 83, 69, 62, and 20 %, respectively (p = 0.039). However, direct comparison showed that the difference between PFS rates in patients receiving R-VACOP-B compared to R-CHOP21 was not statistically significant (p = 0.3). None of the standard clinical risk factors predicted for PFS and OS in patients receiving rituximab (R)-chemotherapy. Mid-interim FDG-PET/CT scans were performed in 30/43 patients who received R-chemotherapy. The negative predictive values of mid-PET activity were high (100 % for R-VACOP-B and 86 % for R-CHOP21) while the positive predictive values (PPV) were relatively low (30 and 75 %, respectively). Despite the low PPV, the 5-year PFS for mid-PET-negative patients (N = 16) was significantly higher (94 %) than that for mid-PET-positive (N = 14) patients (57 %, p = 0.015). This retrospective analysis demonstrates that the superiority of VACOP-B over CHOP21 for treatment of PMBCL disappeared once rituximab was added. The potential benefit of using interim PET activity as a guide for continuing therapy in patients with PMBCL remains unclear due to the relatively low PPV.
authors.affiliation: Division of Hematology and Bone Marrow Transplantation, Chaim Sheba Medical Center, Tel-Hashomer, Ramat-Gan, 5265601, Israel, abraham.avigdor@sheba.health.gov.il.
authors.forename: Abraham
authors.initials: A
authors.lastname: Avigdor
authors.forename: Tsvi
authors.initials: T
authors.lastname: Sirotkin
authors.forename: Meirav
authors.initials: M
authors.lastname: Kedmi
authors.forename: Elena
authors.initials: E
authors.lastname: Ribakovsy
authors.forename: Miriam
authors.initials: M
authors.lastname: Berkowicz
authors.forename: Yaron
authors.initials: Y
authors.lastname: Davidovitz
authors.forename: Abraham
authors.initials: A
authors.lastname: Kneller
authors.forename: Drorit
authors.initials: D
authors.lastname: Merkel
authors.forename: Yulia
authors.initials: Y
authors.lastname: Volchek
authors.forename: Tima
authors.initials: T
authors.lastname: Davidson
authors.forename: Elinor
authors.initials: E
authors.lastname: Goshen
authors.forename: Sara
authors.initials: S
authors.lastname: Apter
authors.forename: Avichai
authors.initials: A
authors.lastname: Shimoni
authors.forename: Isaac
authors.initials: I
authors.lastname: Ben-Bassat
authors.forename: Arnon
authors.initials: A
authors.lastname: Nagler
mesh_terms: D000293:Adolescent; D000328:Adult; D058846:Antibodies, Monoclonal, Murine-Derived / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000627:therapeutic use*; D001761:Bleomycin / Q000008:administration & dosage; D003520:Cyclophosphamide / Q000008:administration & dosage; D004317:Doxorubicin / Q000008:administration & dosage; D004341:Drug Evaluation; D005047:Etoposide / Q000008:administration & dosage; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D006801:Humans; D053208:Kaplan-Meier Estimate; D016403:Lymphoma, Large B-Cell, Diffuse / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D008297:Male; D008479:Mediastinal Neoplasms / Q000000981:diagnostic imaging* / Q000188:drug therapy*; D008875:Middle Aged; D064847:Multimodal Imaging; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011241:Prednisone / Q000008:administration & dosage; D011379:Prognosis; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D000069283:Rituximab; D016879:Salvage Therapy; D014057:Tomography, X-Ray Computed; D014750:Vincristine / Q000008:administration & dosage; D055815:Young Adult
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D001761:Bleomycin; D000069283:Rituximab; D014750:Vincristine; D005047:Etoposide; D004317:Doxorubicin; D003520:Cyclophosphamide; D011241:Prednisone