ABSTRACT
BACKGROUND: Primary central nervous system-diffuse large B-cell lymphoma (PCNS-DLBCL) is a rare extra-nodal Non-Hodgkin lymphoma. There is relative paucity of literature on PCNSL from Indian subcontinent. We aimed to analyze the clinicopathological features of PCNSL and categorize them into germinal center B cell (GCB) and non-GCB subtypes to assess their prognostic significance in Indian context. METHODS: All patients with histopathologically diagnosed PCNSLs at our center over a period of 6 years were recruited and classified into GCB and non-GCB using Han's algorithm (immunohistochemistry for CD10, BCL6 and MUM1). In situ hybridization (ISH) for Epstein-Barr virus (EBV)-encoded RNA was performed. RESULTS: Eighty-six cases of PCNS-DLBCL were included with median age of 55 years. Majority of them were supratentorial in location (n = 62). All patients were immunocompetent. On immunohistochemical assessment, 69 (80.2%) were of NGCB subtype, 10 (11.6%) were of GCB subtype, and 7 (8.1%) were unclassified. Overall, MUM1, BCL-6, and CD10 expressions were seen in 69 (80.2%), 28 (32.6%), and 2 cases (2.3%), respectively. Four cases (4.6%) showed C-MYC expression. The median overall survival (OS) was 675 days. None of the factors (age, sex, location, immunomarkers, and GCB vs. NGCB phenotype) showed correlation with OS; however, BCL6 positive cases showed slight better OS (P > 0.05). All cases were negative for EBV-LMP1 on ISH. CONCLUSION: The majority of the CNS DLBCL belongs to non-GCB phenotype and uniformly carry poor prognosis, irrespective of their phenotype. Individual markers, such as BCL-6, MUM1, or CD10, are unable to predict outcome in PCNS-DLBCL.
ABSTRACT
PURPOSE: This study aimed to calculate the expansion margins around enlarged pelvic lymph nodes to encompass internal motion and setup errors during intensity modulated radiation therapy with simultaneous integrated boost for cervical cancer. METHODS AND MATERIALS: Four-dimensional computed tomography scans were obtained for 19 patients with cervical cancer, and 32 fluorodeoxyglucose-avid pelvic lymph nodes were delineated in different respiratory phases to calculate respiratory displacement. Setup variations during daily treatments were estimated from on-board imaging. Descriptive statistics were used to quantify the expansion margins using Mc Kenzie and Van Herk formulas separately. An analysis of variance was used to analyze the volumetric impact of the margins. RESULTS: Based on the McKenzie formula, an internal margin (internal target volume) of 3 mm and setup margin (planning target volume) of 5 mm was required to adequately encompass respiratory and setup uncertainties, respectively. Although the use of the Van Herk formula necessitated a single 6 mm expansion margin for all uncertainties, which resulted in a significant reduction in boost volume, inherent limitations in our methodology might pose a higher risk of target miss with such smaller margins. CONCLUSIONS: An isotropic expansion margin of 3 mm for the internal target volume and 5 mm for the planning target volume is necessary for enlarged pelvic lymph nodes while planning intensity modulated radiation therapy with simultaneous integrated boost for cervical cancer.
