Intensity-Modulated Radiotherapy for Early-Stage Primary Gastric Diffuse Large B-Cell Lymphoma: Dosimetric Analysis, Clinical Outcome and Quality of Life
Menée sur 46 patients atteints d'un lymphome gastrique diffus à grandes cellules B de stade précoce, cette étude évalue, du point de vue de la dose de rayonnements reçus, de la toxicité, de la survie et de la qualité de vie des patients, l'intérêt d'une radiothérapie avec modulation d'intensité
Purpose : To evaluate the dosimetric superiority, efficacy, toxicity and quality of life (QOL) data of intensity-modulated radiotherapy (IMRT) in patients with primary gastric diffuse large B-cell lymphoma (PG-DLBCL). Methods and Materials : Forty-six consecutive patients with early-stage PG-DLBCL underwent IMRT after chemotherapy. The majority of patients (61.5%) were subclassified as the non-germinal center B cell-like subtype. Dosimetric parameters of the planning target volume (PTV) and organs at risk were assessed. Survival rates were depicted with the Kaplan-Meier method and compared with the log-rank test. QOL was evaluated using the QLQ-C30-STO22 questionnaires at the last follow-up contact. Results : The median PTV mean dose was 41.6 Gy. Only 0.73% of the PTV received <95% of the prescribed dose, indicating excellent target coverage. The median kidney V20 and liver V30 were 14.1% and 16.1%, respectively. The 5-year overall survival (OS), progression-free survival (PFS) and locoregional control (LRC) rates for all patients were 80.4%, 75.0% and 93.2%, respectively. The stage, lactate dehydrogenase level and immunophenotype were significant prognostic factors for OS, and only stage was a significant factor for LRC. Consolidation IMRT in patients with complete response (CR) after chemotherapy resulted in significantly better OS and PFS than salvage IMRT in patients with non-CR. Two of eight patients who had chronic liver disease experienced grade 4 or grade 5 acute hepatic failure after 4–5 cycles of rituximab-based chemotherapy and IMRT (40 Gy). No other serious acute or late toxicity was observed. The long-term global and functional QOL scales were excellent, with negligible symptom scales. Conclusions : IMRT yielded excellent target coverage and critical tissue sparing, and achieved favorable outcomes with acceptable toxicity and good long-term QOL in early-stage PG-DLBCL.