Treatment of Recurrent Prostate Cancer
Prostate cancer that is detected following initial treatment with surgery, radiation therapy, and/or hormonal therapy is considered a recurrence or relapse. Prostate cancer that is resistant (does not respond) to hormonal therapy is also referred to as stage D3.
Treatment for recurrent/relapsed prostate cancer depends on the treatments a patient has previously received as well as the extent of the cancer. In some patients, a rise in PSA level is the only evidence of recurrent cancer. Other patients will have evidence of recurrent cancer on x-rays or scans.
If the patient had surgery to remove the prostate and the cancer comes back only in a small area near the operation, radiation therapy may be given.
If the patient already received radiation therapy to the prostate or to the area of the operation after a radical prostatectomy, radiation therapy usually cannot be administered again to the same part of the body.
Systemic therapy using hormonal or chemotherapy treatment is typically given if tests show that the prostate cancer has spread to other parts of the body. Radiation therapy may be given to relieve symptoms, such as bone pain.
When prostate cancer continues to grow despite hormone therapy, it is called hormone-refractory prostate cancer. Patients with hormone-refractory prostate cancer have historically had few treatment options.
Radiation Therapy for Recurrent Prostate Cancer After Surgery
Radiation therapy may be recommended for patients following surgical prostatectomy if there is cancer in the margins of the surgical specimen, or if their PSA is elevated, and there is no evidence of cancer elsewhere in the body. For some patients, the remaining cancer will be confined to an area near the prostate gland. For many, the cancer will have spread to more distant locations in the body. The difficult question faced by the patients is: What is the chance that additional radiation therapy can eliminate persistent cancer?
In general, 75 percent of patients treated with radiation after prostatectomy will still experience recurrence of cancer within 5 years of radiation therapy. The high rate of failure following radiation therapy occurs because the radiation could not kill all of the cancer cells or because many undetectable cancer cells had already spread beyond the limited reach of the radiation therapy.
Patients must decide whether receiving additional radiation therapy (along with its inconvenience and toxicity) is likely to be beneficial, or whether participation in clinical studies directed at treating cancer that has already spread away from the radiation field is more appealing in offering potential benefit with additional treatment.
Hormone-Refractory Prostate Cancer (D3)
Patients with recurrent prostate cancer after radiation therapy are usually treated with hormone therapy. Hormone therapy removes the male hormones necessary for prostate cancer to grow. Hormone therapy can affect the growth of prostate cancer everywhere in the body, whether the cancer cells are in the prostate itself or elsewhere. Recurrent prostate cancer usually can be controlled with hormone therapy for a period of time, often several years. Eventually, however, most prostate cancers continue growing despite the hormone therapy.
Hormone therapy may be administered surgically (orchiectomy) or with drugs. While hormonal therapy can prevent prostate cancer growth and improve symptoms, it is not a cure.
Chemotherapy has been shown to reduce the severity and duration of pain and improve overall well-being of patients with hormone-refractory prostate cancer. When treatment with chemotherapy was directly compared with no chemotherapy, the men treated with chemotherapy experienced less severe pain. Taxotere® (docetaxel), with or without the chemotherapy drugs Emcyt® or Estracyte® (estramustine), has been found to be particularly effective for recurrent prostate cancer.
Treatment of Bone Complications
Patients with recurrent prostate cancer often have cancer spread to the bones (bone metastases). Bone metastases commonly cause pain, increase the risk of fractures, and lead to a life-threatening condition characterized by an increased amount of calcium in the blood (hypercalcemia). Treatments for bone complications may include bisphosphonate drugs or radiation therapy.
Bisphosphonate drugs - Bisphosphonate drugs can effectively treat bone metastasis by preventing bone loss, reducing the risk of fractures, and decreasing pain associated with bone metastasis. FDA-approved bisphosphonates for the treatment of cancer-related skeletal complications include Zometa® (zoledronic acid) and Aredia® (pamidronate).
Radiation therapy - Pain from bone metastases may also be relieved with radiation therapy directed to the affected bones. The side effects of radiation therapy for relief of bone pain depend on the area of the body being treated. Radioisotopes, such as strontium-89, can be used to treat bone pain. Strontium-89 is given through a vein and accumulates in the bones where it kills prostate cancer cells by delivering small amounts of radiation. Since strontium-89 is given through a vein, it can affect all bones in the body, whereas external radiation therapy is limited to only small areas of the body. The major side effect of strontium-89 is a reduction in blood cell counts.
Another form of radioisotope is Quadramet (samarium). Recent studies combining samarium with certain chemotherapy drugs suggests the combination can not only relieve bone pain, but actually prolong survival.
Research is in progress to refine existing treatments and develop new ones. For information on some of the techniques currently under investigation, see Strategies to Improve Treatment.
This content was last reviewed
August 15, 2010 by Dr. Reshma L. Mahtani.