Monitoring PSA Levels After Prostate Cancer Treatment
- The most important tool physicians use to monitor you after prostate cancer treatment is a blood test that measures something called prostate-specific antigen, or PSA, levels.
- However, a spike in PSA levels does not always mean cancer has returned or that treatment is required right away.
- Your medical team will look at several factors to determine if more treatment is necessary after this rise in PSA levels or “biochemical recurrence,” including how long it took for PSA to rise after treatment, what sort of treatment you received, and other factors from your original diagnosis like Gleason score.
- Additional tests or scans may be required to determine the best next steps.
However, a spike in PSA levels does not always mean cancer has returned or that treatment is required right away. But a rising PSA level might indicate that additional testing and imaging are required.
Read MoreWhat Is PSA & How Is It Monitored?
PSA is a protein made by cells in the prostate gland (both cancerous and non-cancerous). While its use for initial cancer screening can be a topic of debate, there’s widespread agreement that once you’ve been diagnosed and treated for prostate cancer, PSA is an excellent marker to track your progress. It’s highly specific to prostate tissue, meaning if it’s present in your blood after treatment, it could indicate that some prostate cells (or even cancer cells) are still there or have returned.Regular evaluation of your serum PSA is considered the mainstay of surveillance testing after therapy for localized prostate cancer. It’s incredibly sensitive, meaning it can often pick up signs of recurrence even when very small amounts of cancer might be present, long before it could be seen on scans or cause any symptoms. In fact, PSA levels are elevated in 95% of men who experience a recurrence.
While there aren’t specific large-scale studies that dictate the absolute perfect frequency of PSA testing, physicians generally follow the guidelines from leading cancer organizations like the National Comprehensive Cancer Network (NCCN). It’s recommended that your serum PSA be monitored every 6 to 12 months for the first five years after treatment, and then annually thereafter.
The duration of follow-up can be tailored based on your individual risk factors, age, other health conditions, and preferences.
Biochemical Recurrence
What is considered a “biochemical recurrence” varies based on what sort of treatment you received.
“We call biochemical recurrence a detectable PSA after radical prostatectomy,” Dr. Efstathiou explains. “Detectable PSA is a level of 0.2 and above. If you had radiation, it gets more complicated, because you did not remove the prostate, and … it’s a prostate, they might want to start making some PSA again. So biochemical recurrence in the face of prior radiation is a different thing.”
After Surgery (Radical Prostatectomy)
When you undergo radical prostatectomy, the goal is to remove all prostate tissue. Therefore, any detectable PSA in your blood after surgery (even a very low level, typically above 0.1 ng/mL or 0.2 ng/mL, which is the limit of detection for standard tests) theoretically indicates that some prostate tissue remains and might represent persistent or recurrent disease.
After Radiation Therapy (RT) or Brachytherapy
Defining a recurrence after radiation therapy is a bit more nuanced because, unlike surgery, radiation leaves the prostate gland in place. This means there’s still some benign prostate tissue remaining, which can produce PSA.
The American Society for Radiation Oncology (ASTRO) has established clear guidelines for this. According to the 2005 Phoenix criteria, a biochemical failure is defined as a PSA rise of 2 ng/mL or more above your lowest PSA level (called the “nadir PSA”). So, if your PSA reached 0.5 ng/mL at its lowest after radiation, and then went up to 2.5 ng/mL or higher, that would meet the definition of a biochemical recurrence.
Understanding The ‘PSA Bounce’ After Radiation
It’s important to be aware of a phenomenon called “PSA bounce” that can happen after radiation therapy, especially brachytherapy. Your PSA levels can sometimes go up temporarily after radiation treatment, and then come back down again, without indicating a true recurrence.
Think of it like a car engine that’s just been repaired — it might sputter a bit before it settles into a smooth hum. This fluctuation can be concerning, but it doesn’t necessarily mean the cancer has returned.
Your doctor will interpret these fluctuations with caution, and may recommend repeating the PSA test to see the trend.
What Happens If My PSA Starts To Rise?
Dr. Efstathiou explains that after a rising PSA is detected, it’s important to understand how rapidly it’s going up. This will help determine next steps, which might include an additional test, or imaging like an MRI or PSMA PET scan.
“Thankfully, we now have approved scans that are called PET scans that are using a tracer that’s called PSMA. PSMA is usually found on cancer cells. It’s covered by insurance, as long as the criteria are met, and that is the PSA going up,” Dr. Efstathiou says.
This is a newer and very powerful imaging technique. While it’s not for routine screening, in the setting of a rising PSA after treatment, a PSMA PET scan can be very effective at identifying the site of disease relapse, even at lower PSA levels.
The higher your PSA level, the better the detection rate, but it can still be useful at relatively low levels (e.g., detection rates from 33% at PSA 0-0.19 ng/mL up to 95% at PSA >2 ng/mL).
It’s natural for a rising PSA to trigger worry. However, it’s crucial to understand that a PSA relapse does not necessarily mean an immediate, severe problem or predict imminent death. In many cases, the natural history of a “PSA-only recurrence” (where PSA is rising but there are no other signs or symptoms of disease) can be quite prolonged.
This is not to say it should be ignored, but rather that it gives your medical team time to strategize and act. Many recurrences discovered this way can be successfully treated. In fact, intervening when the PSA is still very low can even help prolong survival.
Prognosis: Understanding Next Steps
To help guide decisions, your care team will look at other factors beyond just the rising PSA number.
These “prognostic factors” help doctors understand the likely behavior of the recurrence, and might include:
- Time to Biochemical Recurrence: Understanding how long it took for your PSA to start rising after your initial treatment is key. If it took many years, it often suggests a less aggressive recurrence than if it rises very quickly.
- PSA Doubling Time: This means how quickly your PSA level is increasing (how long it takes for the PSA level to double). A slower doubling time often indicates a less aggressive recurrence.
- Gleason Score: This score, determined from your initial biopsy or surgery, reflects how aggressive your cancer cells looked under the microscope. A higher Gleason score generally indicates a more aggressive cancer.
“If the biochemical recurrence is rapid enough that that PSA is doubling, really, within six months, then it becomes a more urgent issue, and you might even consider doing things even if you don’t see anything on the PET scan,” says Dr. Efstathiou.
Questions To Ask Your Doctor
- How often should I have my PSA checked based on my treatment and risk factors?
- What PSA level or change would make you concerned about a recurrence?
- If my PSA starts to rise, what scans or tests will we do first?
- How does my Gleason score and initial pathology affect my risk of recurrence?
- What treatment options would you recommend if I have a biochemical recurrence?
Content independently created by SurvivorNet with support from Novartis Pharmaceuticals Corp.
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