Usually after surgery to remove the prostate, PSA levels in the blood decrease and eventually become almost undetectable. After radiation therapy, PSA levels usually drop to a stable and low level.

If PSA levels begin to rise at any time after treatment, a local or distant recurrence may be occurring, requiring additional testing.

Prostate cancer can recur locally in the tissue next to the prostate or in the seminal vesicles (two small sacs next to the prostate that store semen). The cancer may also affect the surrounding lymph nodes in the pelvis or lymph nodes outside this area.

Prostate cancer can also spread to tissues next to the prostate, such as the muscles that help control urination, the rectum, or the wall of the pelvis. Prostate cancer can also recur distantly in bones or other organs. This spread is called metastasis.

How Common Is Recurrence of Prostate Cancer?

Nearly 100% of men with prostate cancer can expect to live at least five years after the initial diagnosis. According to the American Cancer Society, 93% of men diagnosed with prostate cancer survive at least 10 years and 77% survive 15 years. Since many men who get prostate cancer are already elderly, they are more likely to die from other causes than the cancer.

More than 90% of the time prostate cancer is discovered while it is either confined to the prostate gland or has spread beyond the prostate only to a small degree, referred to as regional spread.

Among the less than 10% of men whose prostate cancers have already spread to distant parts of the body at the time of diagnosis, about 34% are expected to survive at least five years.

How Is a Recurrence Detected?

After prostate cancer treatment, you will go for medical check-ups every few months as determined by your doctor. At each follow-up appointment, your doctor will order a blood test to measure PSA levels. This test helps your doctor detect a cancer recurrence.

When PSA test results suggest that the cancer has come back or continued to spread, X-rays or other imaging tests (such as a bone scan) may be done, depending on your situation and symptoms.

What Factors Determine the Likelihood of Recurrence?

Several signs can point to a prostate cancer that has come back or spread, including:

Lymph node involvement. Men who have cancer cells in the lymph nodes in the pelvic region may be more likely to have a recurrence.
Tumor size. In general, the larger the tumor, the greater the chance of recurrence.
Gleason score. The higher the grade, the greater the chance of recurrence. Your doctor can tell you your score when the biopsy results come back from the laboratory.
Stage. The stage of a cancer is one of the most important factors for selecting treatment options, as well as for predicting future outlook of the cancer.