Carcinoma blood flow rate

Fig. 4.3. Variability of blood flow rates in solid tumors (see = squamous cell carcinomas, modified from Vaupel and Hockel 2000)...

Corticosteroids are used in clinical practice to relieve pressure symptoms caused by many tumor types, notably intracerebral tumors but also those causing airway or central venous obstruction. Their mode of action has been studied in animals (57) and humans (58), and is thought to involve first constriction of tumor vascular volume and then a reduction in water content. Reduced interstitial pressure should increase perfusion and extravascular diffusion rates, and high doses of steroids have been shown to increase blood flow in human colonic tumors transplanted into mice. Uptake of antibody into tumors has been assessed before and after administration of high-dose dexamethasone to decrease tumor interstitial pressure and thus increase antigen accessibility. Three patients with recurrent colorectal carcinoma had two antibody scans each, 72 h apart, and the injected dose was the same for all scans (20 mg). Dexamethasone was started 24 h before the second dose of antibody, with an initial iv dose of 10 mg followed by 4 mg four times daily orally for 48 h. 

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