The ability of hormone treatment to continue controlling your cancer over the years is quite variable. Some men (approximately 1 in 5) have recurrent cancer growth within a year from starting hormone treatment. Others have no sign of recurrent disease after 10 years of treatment.
For men with metastatic disease (cancer present in areas of the body remote from the prostate), the average time to active cancer growth (hormone resistance) is about 3 years. This stage is sometimes called ‘castrate resistance’.
When resistance to hormone treatment occurs, it is usually indicated by rising PSA while testosterone levels remain low. Symptoms typically occur months to years after the rising PSA. Symptoms caused by growth of the cancer in the pelvic region may include blood in the urine and reduced ability to pass urine. Symptoms caused by growth of the cancer at distant sites such as the bones may include pain in the bones, pelvis and back.
Treatment options for hormone-resistant cancer
1. Changing the type of hormone treatment. Even when one type of drug ceases to work, others may remain active. The order in which you have drugs can also change their effectiveness. Consequently different types and combinations of drugs may be effective. This is called ‘secondary hormone manipulation’.
2. Chemotherapy for prostate cancer is an area of research. A range of newer agents and methodologies are showing promise. Docetaxel is a chemotherapy agent used successfully for other cancers. It has been shown to extend life and reduce pain for prostate cancer. Discussion regarding pros and cons of chemotherapy options usually involves a medical oncologist. This should occur early on when considering approaches to treating hormone resistant prostate cancer.
3. Radiotherapy may alleviate pain and control cancer growth at sites away from the prostate. It is usually delivered by external beam although agents which are injected are sometimes used.
4. Steroids such as prednisolone to control pain and reduce tumour growth.
5. New treatments and clinical trials. Trials of drugs including one called ‘Abiraterone’ are currently underway in Australia. You can search for trials on the ANZ Clinical Trials Registry website listed under Resources, or ask your doctor about clinical trials that could be helpful to you.
Protecting the bones
Hormone treatment is known to weaken bones over time and increase the risk of a break or fracture. A DEXA scan for bone strength is a common investigation for men on or beginning hormone treatment. This is safe and readily available.
To maintain bone strength, it is wise to have an active exercise program and to maintain a balanced diet with adequate calcium intake. Exposure to sunlight stimulates the production of vitamin D, which is also important to bone health. A supplement of vitamin D and calcium is often recommended.
Prostate cancer may spread to the bones, where metastases can lead to bone pain and fractures. Your specialist(s) may recommend drugs known as bisphosphonates. Studies show regular use of this drug by men with secondary prostate cancer in the bones reduces bone fractures and bone pain. These drugs help to retain bone density but they have side effects. It is important to talk to your doctor about these.The drugs can be taken orally or by injection.
Radiotherapy is also used to effectively control bone pain and metastases.