Guessing that you already know all fo the following...But I sure wouldn't take it without my Doc knowing about it:
Unfortunately, estramustine phosphate also affects normal, healthy cells and therefore it produces serious side-effects during long-term treatment. The most important side effect is in the bone marrow where blood cells are made. Regular blood tests may therefore be needed to prevent the damage becoming permanent.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
Inability of the heart to pump blood efficiently (heart failure)
Decreased production of blood cells by the bone marrow (bone marrow suppression)
Alteration in results of liver function tests
Abnormal enlargement of breasts in men (gynaecomastia)
Nausea and vomiting
Chest pain (angina)
The side effects listed above may not include all of the side effects reported by the drug's manufacturer.