OBJECTIVES: I. Determine the toxicity profile, including dose limiting toxicity, and maximum tolerated dose (MTD) of combretastatin A4 phosphate in patients with advanced solid malignant tumors. II. Determine the pharmacokinetics of combretastatin A4 phosphate. III. Assess the effects of combretastatin A4 phosphate on tumor blood flow using PET and MRI scanning techniques, and establish the dose at which these effects occur. IV. Recommend a dose of combretastatin A4 phosphate for phase II evaluation based on tumor blood flow effect and the MTD. V. Evaluate possible antitumor effects of this regimen in these patients.