Treatment Outcomes And Dosimetric Evaluations In Patients With Primary Mediastinal Large B-cell Lymphoma Receiving Combined Modality Therapy And Intensity-modulated Radiotherapy

Fart Ⅰ:Prognostic significance of rituximab and radiotherapy for patients with primary mediastinal large B-cell lymphoma receiving doxorubicin-containing chemotherapyPurpose:To evaluate the prognostic importance of rituximab and radiotherapy in patients with primary mediastinal large B-cell lymphoma (PMBCL) receiving doxorubicin-containing chemotherapy.Patients and methods:Seventy-nine patients with PMBCL received CHOP chemotherapy with (n=39) or without rituximab (n=40), and60patients received additional radiotherapy.Results:Patients treated with R-CHOP had significantly superior survival rates. The5-year overall survival (OS) and progression-free (PFS) rates were83.7%and76.7%for R-CHOP, compared with48.3%(p=0.011) and44.2%(p=0.012) for CHOP, respectively. Similarly, the5-year OS and PFS rates for early stage patients were93.8%and84.6%with R-CHOP, and52.0%(p=0.002) and46.6%(p=0.003) with CHOP, respectively. Patients treated with chemotherapy and radiotherapy had better survival and LC rates compared with chemotherapy alone. The5-year OS, PFS and LC rates for early stage patients were73.6%,69.9%and92.6%for chemotherapy and radiotherapy, and50.8%(P=0.076),36.9%(P=0.008) and56.4%(P<0.001) for chemotherapy alone, respectively. Early stage patients treated with R-CHOP and radiotherapy had5-year OS, PFS and LC rates of96.4%,85.9%and93.1%.Conclusion:R-CHOP plus consolidation radiotherapy was associated with excellent survival and LC rates. PART II:Dosimetric evaluation and treatment outcome of intensity-modulated radiation therapy following doxorubicin-based chemotherapy for primary mediastinal large B-cell lymphomaPurpose:The value of intensity-modulated radiotherapy (IMRT) following doxorubicin-based chemotherapy in primary mediastinal large B-cell lymphoma (PMBCL) is unknown. We assessed the dosimetric parameters, treatment outcomes and toxicity of IMRT in PMBCL.Methods and Materials:Forty-one PMBCL patients underwent mediastinal IMRT following doxorubicin-based chemotherapy (38stage I-II patients, three stage III-IV patients). Most patients presented with bulky mediastinal disease (65.9%) and local invasion (82.9%).Results:The average planning target volume (PTV) mean dose was39Gy. Only0.5%and1.4%of the PTV received<90%and<95%of the prescribed dose, respectively, indicating excellent target coverage. Median mean lung dose and percentage lung volume receiving20Gy (V20) were16.3Gy and30.6%. Five-year overall survival (OS) and local control (LC) were95.1%and89.8%. After chemotherapy, consolidation radiotherapy in patients with complete/partial response resulted in significantly better survival than salvage radiotherapy in patients with stable/progressive disease (3-year OS100%vs.75%;3-year LC96.6%vs.62.5%). No Grade4or5acute or late toxicities occurred.Conclusions:Mediastinal IMRT following doxorubicin-based chemotherapy can be safely and efficiently delivered, and it provides favorable outcomes in PMBCL patients with a large target volume and high-risk features.