In contrast to oral synthetic estrogens like EE and diethylstilbestrol, high-dosage polyestradiol phosphate and transdermal estradiol have not been found to increase the risk of cardiovascular mortality or thromboembolism in men with prostate cancer. However, significantly increased cardiovascular morbidity has been observed with high-dosage polyestradiol phosphate. In any case, these estrogens are considered to be much safer than oral synthetic estrogens like EE and diethylstilbestrol. In addition, ethinylestradiol sulfonate (EES), an oral but parenteral-like long-lasting prodrug of EE, is used in the treatment of prostate cancer, and is said to have a considerably better profile of cardiovascular safety than EE.