Prostate cancer recurrence is the return of cancer after initial treatment, such as surgery or radiation, was believed to have removed all malignant cells. This return can occur locally, near the original site, or distantly, having spread to other parts of the body. Recurrence often happens within the first five years following initial therapy. Detecting the disease relies on both specific medical testing and recognizing certain physical changes.
The Earliest Warning Sign PSA Levels
The most sensitive and earliest indicator of recurrence is a consistent rise in the level of Prostate-Specific Antigen (PSA) in the blood. PSA is a protein produced by prostate cells, and its level is closely tracked following treatment. A rising PSA is often the first sign of cancer return, preceding physical symptoms by months or even years.
This phenomenon is known as biochemical recurrence (BCR), indicating that cancer cells survived the initial treatment and are producing PSA again. Following a radical prostatectomy, the PSA should ideally drop to an undetectable level. BCR is typically defined as a PSA level of \(0.2 \text{ ng/mL}\) or higher, followed by a second, confirming rise.
Following radiation therapy, the PSA level usually declines more slowly to a low, stable point known as the nadir. Recurrence is often defined as an increase of \(2 \text{ ng/mL}\) above that post-treatment nadir. Physicians also track the PSA doubling time, which measures how quickly the level is rising. A faster doubling time suggests more aggressive disease activity.
Physical Signs of Local Return
While biochemical recurrence is usually detected first through blood tests, the cancer may return specifically to the area where the prostate once was or in the immediate surrounding tissues. If the cancer is confined to the genitourinary area, it is considered a local recurrence. These symptoms are distinct from distant spread and are generally related to the urinary and pelvic systems.
Patients may notice blood in the urine, called hematuria, or blood in the semen, known as hematospermia. Difficulty or pain during urination (dysuria) is another sign that the returning cancer may be pressing on the urethra or bladder neck. Other symptoms include unexpected discomfort or pain in the pelvic region or the perineum.
Physical Signs of Distant Spread
If cancer cells have traveled through the bloodstream or lymphatic system to other parts of the body, this is defined as distant spread or metastatic recurrence. Prostate cancer most commonly metastasizes to the bones, but it can also affect the lymph nodes, lungs, or liver.
The most recognizable sign of distant spread is persistent, unexplained pain, particularly in the bones of the back, hips, or ribs. This pain results from cancer lesions growing within the bone structure. Unexplained weight loss, with no change in diet or exercise, can also signal systemic disease progression.
Profound fatigue or weakness that does not improve with rest is a common systemic symptom associated with advanced recurrence. If the cancer has spread to the lymph nodes, especially in the pelvic area, it can cause swelling in the legs (lymphedema). Neurological symptoms, such as weakness or numbness in the legs, may occur if the cancer has spread to the spine and is compressing nerves.
Confirming Recurrence Diagnostic Tools
Once a rising PSA level or physical symptoms suggest a recurrence, physicians use advanced imaging to pinpoint the location of the returning cancer. The choice of diagnostic tool often depends on the patient’s PSA level and prior treatments. The newest and most sensitive technology is the Prostate-Specific Membrane Antigen Positron Emission Tomography (PSMA PET scan).
The PSMA PET scan involves injecting a radioactive tracer that binds specifically to the PSMA protein, which is highly expressed on prostate cancer cells. This allows the scanner to create detailed images that highlight even very small clusters of cancer cells throughout the body. PSMA PET scans have a high detection rate, even at low PSA levels, making them superior to older methods like standard computed tomography (CT) and bone scans for early detection of metastatic disease.
Traditional imaging tools, such as CT scans and bone scans, are still used, but they are less effective at finding microscopic or small, early recurrences. A CT scan provides detailed images of soft tissues and bones, while a bone scan uses a different radioactive tracer to specifically look for areas of increased bone turnover that can indicate metastasis. Sometimes, a targeted biopsy may be performed to confirm the presence of malignant cells and determine the cancer’s grade, especially if the recurrence is suspected to be local.