OBJECTIVES: I. Compare the effect of low molecular weight heparin (dalteparin) plus standard therapy versus standard therapy alone on the overall survival rate of patients with advanced cancers. II. Compare the toxic effects of these regimens and the effect on the quality of life of these patients. III. Assess the incidence of symptomatic thrombotic events such as deep venous thrombosis (DVT), pulmonary embolus (PE), and clotted catheters in these patients.