Assessment of disease dissemination in gastric compared with extragastric mucosa-associated lymphoid tissue lymphoma using extensive staging: a single-center experience.

PURPOSE: Molecular data and preliminary clinical findings have suggested mucosa-associated lymphoid tissue (MALT) lymphoma as a multifocal disease in a high percentage of patients. We report our findings with an extensive staging routine applied in patients diagnosed with MALT lymphoma at our institution. PATIENTS AND METHODS: A total of 140 consecutive patients (61 with gastric and 79 with extragastric MALT lymphoma) underwent staging according to a standardized protocol. Staging included gastroscopy with multiple biopsies, endosonography of the upper GI tract, computed tomography of thorax and abdomen, lymph node sonography, colonoscopy with multiple biopsies, otorhinolaryngologic assessment, magnetic resonance imaging of salivary and lacrimal glands, and bone marrow biopsy. All lesions suggestive of lymphoma involvement were subjected to biopsy, if accessible, and biopsies were evaluated for MALT lymphoma-specific genetic aberrations by means of reverse transcriptase polymerase chain reaction and/or fluorescent in situ hybridization. RESULTS: Fifteen (25%) of 61 patients with gastric MALT lymphoma had multiorgan involvement, with dissemination beyond the GI tract in six patients. By contrast, significantly more patients with extragastric MALT lymphoma had dissemination to another MALT organ (37 of 79 patients, 46%; P = .045). Nine of these 37 patients had dissemination to the stomach. Only three (2%) of 140 patients had bone marrow involvement. Multifocality was significantly associated with t(11;18)(q21;q21) in gastric lymphomas (P = .045) and with trisomy 18 in extragastric lymphomas (P = .011). CONCLUSION: Our findings suggest that MALT lymphoma frequently presents as a multifocal disease. Extragastric MALT lymphomas are significantly more prone to dissemination than gastric MALT lymphomas.

Tumor microvascular changes in antiangiogenic treatment: assessment by magnetic resonance contrast media of different molecular weights.

PURPOSE: To test magnetic resonance (MR) contrast media of different molecular weights (MWs) for their potential to characterize noninvasively microvascular changes in an experimental tumor treatment model. MATERIALS AND METHODS: MD-MBA-435, a poorly differentiated human breast cancer cell line, was implanted into 31 female homozygous athymic rats. Animals were assigned randomly to a control (saline) or drug treatment (monoclonal antibody vascular endothelial growth factor (Mab-VEGF) antibody) group. In both groups, dynamic MR imaging (MRI) was performed in each animal using up to three different contrast media on sequential days at baseline and follow-up examination. The MWs of the contrast media used ranged from 557 Da to 92 kDa. Using a bidirectional kinetic model, tumor microvessel characteristics, including the fractional plasma volume (fPV) and transendothelial permeability (K(PS)), were estimated for each contrast medium. These microvascular characteristics were compared between drug and control groups and between contrast media of different MWs. RESULTS: Tumors grew significantly slower (P < 0.0005) in the drug treatment group than in the control group. Mean K(PS) and fPV values decreased significantly (P < 0.05) in the Mab-VEGF antibody-treated group compared to baseline values using intermediate or macromolecular contrast media (MMCM), but did not change significantly using small molecular contrast media (SMCM). In the control groups, mean K(PS) and mean fPV values did not reach statistical significance for any of the contrast media used. CONCLUSION: Therapeutic effects of a Mab-VEGF antibody on tumor microvessel characteristics can be monitored by dynamic MRI. Intermediate-size agents, such as Gadomer-17, offer a substantial dynamic range and are less limited by imaging precision and therefore should be considered a practical alternative to monitor antiangiogenesis treatment effects in a clinical setting.