Article
Capillary permeability, blood volume and regional blood flow in primary CNS lymphomas – Impact on drug delivery
Kapilläre Permeabilität, Blutvolumen und regionale Durchblutung in primären ZNS-Lymphomen - Einfluss auf die Chemotherapie
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Published: | April 23, 2004 |
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Outline
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Objective
Primary CNS lymphomas represent a unique intracerebral tumour entity being chemosensitive to water-soluble drugs in almost up to 70% of cases. These clinical findings indicate different vascular physiology of lymphomas resulting in favourable drug delivery parameters.
Methods
Blood-brain transport (K1), brain-blood transport (K2) plasma vascular space and the size of the extracellular space were measured using dynamic spiral-CT and tumoural blood flow was assessed using stable-Xenon CT in 7 patients. All patients were off steroids and untreated. Histology was verified from stereotactic biopsies.
Results
Capillary permeability (K1) ranged from 16.1 ± 14.2 to 43.5 ± 30.3 μl /gm/min with a mean of 29.47 ± 10.6. Vascular space ranged from .002 ± .007 to .065 ± .075 ml/gm with a mean of .027 ± .024. The efflux constant (K2) showed a mean of 58.3 ± 44 min and the extracellular space showed a mean of .33 ± .27 ml/gm with a range of .19 to .42 ml/gm. Tumoural blood flow showed a mean of 43.16 ± 12.4 ml/100g/min as compared to normal brain with a 52.3 ± 13.4 ml/100g/min. pillary permeability was significantly increased in lymphomas (p<.001 for GBM, p<.005 for medulloblastomas and p<.01 for metastases) and blood flow was not significantly different from that of normal brain (p>.05, t-test).
Conclusions
Primary CNS lymphomas form a unique tumour entity within the brain with a high capillary permeability for water-soluble compounds and a small extracellular space, thus reducing the sink effect for chemotherapy. Also blood flow is higher than in all other measured brain tumours.