Outcome Of Localized And Advanced Diffuse Large B-Cell Non-Hodgkin Bone Lymphoma (Dbl)

18527 Background: DBL represents less than 2% of all lymphomas in adults. Over the years, combined-modality treatment (CMT) using an anthracycline-based chemotherapy regimen (ChT) and radiotherapy (RT) has emerged for the treatment of localized DBL (LDBL). Methods: Data were collected from the HMR oncology orthopaedic data bank. Thirty patients with localized and advanced DBL at diagnosis treated at HMR between December 1993 and August 2004 were included. Primary end-points were event-free survival (EFS) and overall survival (OS). Statistical analyses were performed using Kaplan-Meier and Cox proportional hazard models. Results: The median follow-up was 38.6 months. Fourteen patients had limited stage I-II disease while 16 patients had stage IV disease. Femur (33%) and spine (33%) were the most frequently involved bone sites. Ten patients had bulky disease (>10cm). Patients were treated as followed: 50% with CMT, 33% ChT alone and 17% only RT. CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) was the only chemotherapy regimen used. Four patients received rituximab (R-) combined with CHOP. Patients received an average of 5 cycles of ChT (range 1–8). RT dose was between 30 and 40 Gy for 70% of patients. Doses of 30 Gy and higher show a tendency to offer an OS advantage (hazard ratio (HR) =0.2, 95%CI 0.03- 1.35). The 5-year estimates EFS and OS were respectively 48% (95%CI 27%-71%) and 60% (95%CI 38%-82%) for the whole group and 70% (95%CI 50%-99%) and 81% (95%CI 57%-99%) for patients with LDBL. All four patients treated with R-CHOP have a sustained complete remission (CR). Patients receiving CMT have significantly improved EFS (p=0.02, HR=0.25, 95%CI0.08–0.83) but not OS. Patients with advanced disease may benefit from CMT for EFS (HR=0.23, 95%CI 0.05–1.12). Factors which adversely affect EFS and/or OS (univariate analyses) are: stage IV disease (p<0.05 EFS/OS), axial localisation (p<0.05 EFS) and IPI 4 (p=0.072 EFS, p<0.05 OS). Conclusion: This study supports CMT as an efficient treatment for DBL. Patients treated with R-CHOP have a favourable outcome. RT dose of 30–40 Gy appears sufficient to obtain a prolonged CR. No significant financial relationships to disclose.