Main Research Findings

Estramustine phosphate (EMP) is a medication used to treat castration-resistant prostate cancer. Although the standard dosage of 560 mg daily has a favorable toxicity profile, the tolerability and toxicology of EMP have raised concerns during administration. 7 Furthermore, it is unclear whether a lower dosage of 280 mg EMP daily can be administered effectively with fewer side effects. The results of our Phase II study suggest that low-dose EMP is a safe treatment option with the same efficacy in patients with castration-resistant prostate cancer. 7 However, it is crucial to note that EMP can lead to increased side effects when used in conjunction with other anticancer drugs. 18 Moreover, EMP can cause side effects such as myelosuppression, 26 , which might necessitate discontinuation of EMP therapy. 5 .

Reasons for Side Effects

EMP possesses estrogenic properties, which can lead to side effects related to estrogen dependence. 3 While EMP inhibits the growth of prostate cancer cells, it can also negatively affect the digestive, circulatory, and blood systems as side effects. 3 EMP is metabolized in the liver, so it has the potential to cause liver dysfunction. 5 .

Common Side Effects

Digestive System

EMP commonly causes digestive system side effects, including nausea, vomiting, and loss of appetite. These side effects are believed to be caused by inflammation of the digestive system mucosa due to EMP administration. 3 Additionally, EMP administration can slow down digestive tract motility, which can contribute to nausea and vomiting. 22 .

Circulatory System

EMP can impact the circulatory system, leading to edema and thrombosis. 3 These side effects are thought to result from increased vascular permeability due to the estrogenic activity of EMP. 3 Additionally, EMP can reduce heart muscle contractility, increasing the risk of heart failure. 3 EMP administration can also cause abnormalities in ECG readings. 3 .

Blood System

EMP administration can lead to myelosuppression. 18 Myelosuppression is a condition where blood cell production is suppressed, causing side effects such as leukopenia, anemia, and thrombocytopenia. 18 EMP is toxic to bone marrow cells, which is believed to be the cause of myelosuppression. 18 Myelosuppression increases the risk of infection and requires close monitoring. 26 .

Other

EMP administration can cause breast swelling, gynecomastia, fatigue, rash, liver dysfunction, fever, and urinary incontinence. 5 9 Additionally, EMP administration can lead to side effects such as thrombocytopenia and anemia. 8 EMP is metabolized in the liver and can cause liver dysfunction. 5 EMP administration can also cause side effects such as uremia. 27 .

Side Effect Management

Digestive System

To mitigate digestive system side effects, consuming meals before EMP administration or frequent small meals can be effective. 3 Taking antiemetics can also help. 3 When taking EMP, it is crucial to be aware that absorption rates decrease when taken with dairy products. 22 EMP can also slow down digestive tract motility, so constipation prevention is essential. 22 .

Circulatory System

To reduce side effects like edema, measures to alleviate swelling, such as resting with feet elevated, are helpful. 3 To lower the risk of thrombosis, staying hydrated and engaging in regular exercise are crucial. 3 For heart failure prevention, regular medical checkups are vital. 3 .

Blood System

To prevent myelosuppression, it is essential to perform blood tests before EMP administration. 18 If myelosuppression is confirmed, EMP dosage should be reduced or discontinued. 18 Administration of drugs such as granulocyte colony-stimulating factor (G-CSF) can also effectively prevent myelosuppression. 18 Myelosuppression increases the risk of infection and requires attention. 26 .

Other

Side effects like breast swelling and gynecomastia may be alleviated by taking estrogen antagonists. 5 Side effects like fatigue can be reduced by getting adequate rest. 5 Side effects like rash can be mitigated by taking antihistamines. 5 To prevent liver dysfunction, regular liver function tests are crucial. 5 Measures like pelvic floor muscle training can be effective in preventing urinary incontinence. 5 .

Comparison between Studies

Similarities among Studies

Multiple studies suggest that EMP is an effective treatment for castration-resistant prostate cancer. Studies also suggest that lower doses of EMP are safer and have fewer side effects compared to standard doses. However, EMP can lead to higher side effect rates when used in combination with other anticancer drugs. Additionally, EMP can cause side effects like myelosuppression, which can lead to discontinuation of EMP therapy.

Differences among Studies

Each study has variations in EMP dosage, treatment duration, concomitant medications, study size, and target patient population, resulting in different findings. It is crucial to consider these differences when comparing research results.

Points to Note Regarding Real-Life Application

EMP is an effective drug for treating castration-resistant prostate cancer, but it can cause side effects. Before starting EMP, it is essential to consult a doctor and determine the appropriate dosage and treatment method for your individual body type. Regular medical checkups are crucial during EMP administration to monitor for side effects. If you experience side effects due to EMP administration, immediately consult a doctor.

Limitations of Current Research

Current research still has many unanswered questions, including the long-term effects of EMP and how EMP interacts with other drugs. Dosage and treatment duration vary for each patient, so more research is needed.

Future Research Directions

Future research should focus on clarifying the long-term effects of EMP and how EMP interacts with other drugs. Research is also needed to optimize dosage and treatment duration for each individual patient.

Conclusion

EMP is an effective drug for treating castration-resistant prostate cancer, but it can cause side effects. Before starting EMP, it is essential to consult a doctor and determine the appropriate dosage and treatment method for your individual body type. Regular medical checkups are crucial during EMP administration to monitor for side effects. If you experience side effects due to EMP administration, immediately consult a doctor.