ABSTRACT
Objective To explore the prognostic factors of primary mediastinal large B-cell lymphoma (PMBCL) and the effects of chemoradiotherapy versus chemotherapy alone on patients' prognosis before and after rituximab era. Methods We extracted the data of PMBCL patients diagnosed from 2001 to 2015 from SEER database. SEER Stat software was used to calculate the incidence rate. Kaplan-Meier method and Cox regression model were used to analyze the impact of various clinical variables on prognosis. Results We included 635 patients with PMBCL. Multivariate Cox regression analysis showed that age, stage and chemotherapy were independent prognostic factors. Kaplan-Meier survival analysis showed that OS of the patients receiving chemotherapy only in 2006-2015 was significantly better than that in 2001-2005 (χ2=10.002, P=0.002). The patients who received chemoradiotherapy had better OS than those who received chemotherapy alone from 2001 to 2005. The OS and DSS of patients receiving chemoradiotherapy were not significantly different from those of chemotherapy alone from 2006 to 2015. Conclusion The application of rituximab improves the long-term survival of PMBCL patients. The prognosis of patients who received chemoradiotherapy is comparable to that of chemotherapy alone from 2006 to 2015.
ABSTRACT
Primary mediastinal large B-cell lymphoma (PMLBL) is an uncommon non-Hodgkin lymphoma with a distinct clinicopathological entity in the WHO classification of lymphoid malignancies. It is known to originate from B-cells of the thymus. It mimics thymic neoplasms and other lymphomas clinically and histopathologically. We reported a 33-year-old obese man who presented with shortness of breath off and on for 4 years. Radiologically, there was a huge anterior mediastinal mass. Tru-cut biopsy was initially diagnosed as type-A thymoma. Histopathological examination of the excised specimen revealed PMLBL with stromal fibrosis and sclerosis which created a diagnostic difficulty. The neoplastic cells varied from medium-sized to large pleomorphic cells, including mononuclear cells with centroblastic and immunoblastic features as well as bi-lobed Reed Sternberg (RS)-like cells and horse-shoe like hallmark cells. Some interlacing spindle cells and epithelioid cells were also present. Immunohistochemically, tumour cells expressed diffuse positivity for LCA, CD20, CD79a, CD23, Bcl2, MUM-1 and heterogenous positivity for CD30 and EMA, and were negative for CD10, CD15 and ALK. Ki67 scoring was very high. Tumour cells infiltrated into peri-thymic fat and pericardium. No malignant cells were detected in the pleural fluid and there was no bone marrow infiltration. The patient showed partial response to 6 cycles of RICE chemotherapy, and was planned for second line chemotherapy using hyper-CVAD regimen followed by autologous stem cell transplantation. This case illustrates the importance of thorough sampling and immunohistochemistry in differentiating PMLBL from its differential diagnoses.
ABSTRACT
Objective To compare target dosimetric distribution and normal tissue radiation between different static intensity?modulated radiation therapy ( IMRT) plans and volumetric modulated arc therapy ( VMAT) and to identify the best IMRT plan for patients with primary mediastinal B?cell lymphoma ( PMBCL) . Methods A total of 16 patients ( 8 males and 8 females) with early?stage ( Ann?Arbor stageⅠ) PMBCL were enrolled in this study,with doses of 45 Gy for primary gross tumor volume ( PGTV) and 40 Gy for planning target volume (PTV).Four plans were designed for each patient,consisting of static IMRT (5F?IMRT,7F?IMRT,9F?IMRT) and VMAT,and the target dosimetric distribution,normal tissue radiation dose,and efficiency of each plan were evaluated. The difference of dose was analyzed by analysis of variance. Results The mean conformity index ( CI) and homogeneity index ( HI) for PGTV in 5F?,7F?,9F?IMRT and VMAT were 1. 01 and 1. 10, 1. 01 and 1. 10, 1. 01 and 1. 10, and 1. 01 and 1. 11 ( P= 0. 963 and 0. 843) ,respectively,while these two indices for PTV were 1. 04 and 1. 22,1. 03 and 1. 19,1. 03 and 1. 17, and 1. 08 and 1. 14( P=0. 964 and 0. 969) ,respectively. The parameters of volume and dose were similar on normal tissue ( P= 0. 192?1. 000 ) . The treatment time and number of monitor units in 9F?IMRT were significantly higher than those in other static IMRT plans and VMAT ( P=0. 000,0. 000) ,and among these plans,VMAT had the lowest number of monitor units ( 13 345. 0 MU) and the shortest treatment time ( 5. 9 min) . Conclusions The target volume coverage of 7F?and 9F?IMRT is better than that of 5F?IMRT and VMAT.For early?stage PMBCL,VMAT is not superior to IMRT in terms of dosimetry,especially with a larger area of low?dose radiation to the breast,but it is highly efficient in practice.
ABSTRACT
Primary mediastinal large B-cell lymphoma (PMBCL) is a unique type of B-cell lymphoma probably arising from a putative thymic medulla B cell.It constitutes 6 ％-10 ％ of all diffuse large B-cell lymphomas (DLBCL),with special pathologic features,immunophenotype and genetic abnormlities,and need to be identified with classical Hodgkin lymphoma and other types of DLBCL.In this review,the pathological features,molecular biological changes,treatment,prognosis and treatment of PET in the evaluation of the initial reaction in PMBCL were summarized.