Treatment of Stage III Prostate Cancer

This content has been reviewed and approved by

Daniel P. Petrylak, MD
Associate Professor of Medicine
Director, Genitourinary Oncology Program
Columbia University Medical Center

Prostate cancer is referred to as stage III if the cancer can be detected by digital rectal examination and has extended through the capsule that encloses the prostate gland. Stage III prostate cancer may involve nearby tissues and is further divided into the following categories, depending on how extensive the cancer is:

• T3a -The tumor has extended outside of the prostate on one side.
• T3b - The tumor has extended outside of the prostate on both sides.
• T3c  -The tumor has invaded one or both of the seminal vesicles, which are small bag-like organs near the bladder.

Patients with stage III disease do not have detectable cancer in the lymph nodes or other distant areas of the body.

Prostate cancer is typically a disease of aging. It may persist undetected for many years without causing symptoms. Some patients with stage III prostate cancer are curable and may be treated with either surgery or radiation therapy. Combinations of different therapies are more successful than single treatments.

To help you make treatment decisions, you should obtain as much information as possible about the results of each type of treatment.. You should also consult more than one physician for a treatment recommendation, especially when deciding between surgery and radiation therapy.

Patients with stage III or "locally advanced" prostate cancer do not have any clinical evidence of cancer spread to the pelvic lymph nodes. This would suggest that the cancer is confined to the prostate and could be effectively treated with local therapy (surgery or radiation).

If your prostate cancer is confined to the prostate, it is curable with surgery and/or radiation. For some patients, however, undergoing radical prostatectomy will be found to have cancer involving the pelvic lymph nodes at the time of surgery. For these patients, the risks and side effects of surgery will have been unnecessary because the surgery cannot cure the cancer.

Before making treatment recommendations, physicians who treat prostate cancer consider the clinical stage of the disease, the prostate-specific antigen (PSA) level, and the appearance of the prostate cancer cells under the microscope. These factors are used to predict how likely the cancer is to grow and how aggressively it will grow.

Patients most likely to benefit from aggressive surgical treatment can initially undergo a simple procedure called a pelvic lymph node dissection. If the lymph node dissection (removal) indicates that the lymph nodes are involved, the patient can be spared surgery.

Radiation Therapy

Radiation therapy uses high energy x-rays that have the ability to kill cancer cells. Standard radiation therapy uses either external beam radiation therapy (EBRT), consisting of daily treatments on an outpatient basis for approximately 6 to 8 weeks, or interstitial brachytherapy, which involves permanent placement of radioactive seeds directly into the prostate gland. Radioactive implants are increasingly being used instead of radical prostatectomy or EBRT.

The actual area of the pelvis receiving radiation treatment may be large or focused only on the prostate. Because patients with stage III prostate cancer often have undetected cancer cells in the pelvic lymph nodes, radiation therapy may be directed to the lymph nodes in the pelvis in addition to the prostate gland. If patients’ symptoms suggest treatment for a larger area of the pelvis, they may undergo another planning session to focus the radiation to the prostate gland, where cancer cells have the highest concentration.

Because radioactive implants focus the radiation closely around the prostate, this form of radiation does not work as well in patients with stage III prostate cancer as in earlier stages unless combined with EBRT. The purpose of the EBRT is to treat the surrounding tissue and lymph nodes, where cancer cells may have spread. The radioactive implant seeds deliver an increased radiation dose to the prostate, where the cancer cells have the highest concentration. The combination of internal radiation and EBRT may permit high doses of radiation to be delivered to the cancer while minimizing side effects to surrounding organs.

Despite treatment with radiation therapy, more than half of patients with stage III prostate cancer will experience cancer recurrence. This is because some patients already have small amounts of cancer that have spread outside the prostate that were not treated by radiation. Undetectable areas of cancer outside the prostate gland are referred to as micrometastases. The presence of micrometastases is thought to cause relapses that follow treatment with radiation alone. An effective treatment is needed to cleanse the body of micrometastases to improve the cure rate achieved with radiotherapy or surgery. Efforts are currently under way to find such a therapy.

Surgery - Radical Prostatectomy

The majority of men with locally advanced prostate cancer are not candidates for surgery because the cancer is likely to have spread beyond the prostate. Before a prostatectomy is performed, you may want to have pelvic lymph nodes removed to see if they contain cancer. This is called a pelvic lymph node dissection. If the lymph nodes contain cancer, usually the surgeon will not proceed with a radical prostatectomy. If there is no evidence of lymph node invasion, you may want to have radical prostatectomy.

Despite undergoing surgical removal of all detectable prostate cancer, many patients with stage III prostate cancer will experience a cancer recurrence. It is important to realize that some patients with stage III disease already have small amounts of cancer that have spread outside the prostate and were not removed by surgery.

Undetectable areas of cancer outside the prostate gland are referred to as micrometastases. The presence of micrometastases is thought to cause relapses that occur following treatment with surgery alone. An effective treatment is needed to cleanse the body of micrometastases to improve the cure rate achieved with surgical removal of the cancer. Efforts are currently under way to find such a therapy.

Watchful Waiting

Some physicians and patients choose a conservative management strategy of watchful waiting. Because treatment with radiation or surgery may be associated with temporary and permanent side effects in addition to inconvenience, choosing not to receive treatment may be appropriate for selected patients.

Elderly patients and/or those with other significant medical problems may experience greater side effects from treatment. Although many patients may require hormonal therapy or radiation therapy to treat symptoms once their disease progresses, radical prostatectomy may not be beneficial for men with a life expectancy shorter than 10 years.

Watchful waiting requires close follow-up of the cancer. Therapy begins only when signs and symptoms of cancer spread emerge. At this point, the treatment is usually hormonal therapy. It is not known for certain whether it is better to treat early or to wait until progression of the disease occurs. To help you decide on treatment, ask your physician to explain your chances of survival without treatment and the risk of cancer having spread beyond the prostate capsule.

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.