Frequently Asked Questions
How accurate is the PSA test when it comes to remission? Can I trust that a low PSA values means I am disease-free?
Your PSA level may lower after treatment. But a low PSA level does not mean the cancer is cured. If PSA is undetectable (after surgery) or low and stable (after radiation), it may mean the cancer has stopped growing. If your PSA is rising, it may mean the cancer is progressing. Or it may not. PSA is produced by all prostate cells, not just prostate cancer cells.
So PSA is not really a marker for the cancer's progress. It is a marker for prostate cell activity. Doctors don't usually look at only one PSA reading. They see how the numbers progress. After surgical removal of the prostate, the PSA level should be undetectable. And after radiation therapy, the PSA should be low, less than 1.0 ng/ml.
The PSA may mean the cancer has come back if the rise is:
- Above 0.2 after surgery to remove the prostate
- 2.0 above the lowest level achieved after radiation therapy
In other words, if a man's PSA fell to 0.2 after radiation therapy, then rose to 0.7, 1.1, 1.4, 1.6, and 1.9, he would still be classified as not having prostate cancer even though his PSA is rising. To be classified as having cancer again, the PSA would need to be at 2.2.
The reason doctors use many tests after radiation is that the PSA can "bounce" or "jump up" after radiation therapy. Then it will come back down to its normal level. If doctors rely on one high PSA, they may test during a bounce. The results would be misleading. The PSA bounce usually happens between 12 months and 2 years after the end of therapy.
If the PSA is rising, the doctor might want to start therapy anyway. PSA is only one of many things to consider. The original clinical stage of disease, the Gleason score of the tumor, the PSA before diagnosis, the overall health, and general life expectancy are key factors in the decision. So be prepared to talk about treatment choices even if you don't fit the classical categories for PSA rise after the first treatment.
On the other hand, if your PSA is rising and you do fit the categories above, that doesn't necessarily mean a return of cancer. Researchers have found that PSA cut-offs might not be enough for truly understanding how prostate cancer grows.
What are bones and skeletal related events (SREs)?
Prostate cancer is usually a disease of the aging male. Older men with prostate cancer are at risk for bone and mineral loss. This can lead to bone weakening (osteopenia) and bone loss (osteoporosis). Low testosterone and castration makes this worse. If you have prostate cancer you should take calcium and vitamin D and do weight bearing exercises.
Men with prostate cancer spread to the bones are at risk for "skeletal-related events (SREs)." These include bone fractures and need for surgery to prevent fracture. Two approved medications reduce SREs. Zolendronic Acid helps reduce bone turnover. It has been shown to reduce SRE's in men with CRPC. It is given by IV every three to four weeks. Side effects include low calcium, worsening kidney function and, rarely, destruction of the jaw bone. So, you are monitored closely. You should have a dental exam before starting the drugs.
A second approved drug for SREs is Denosumab. It reduces bone turnover. It is approved for men on hormone therapy and men with CRPC. Doses depend on the disease state. The drug is given under the skin.
In a study comparing denosumab to Zolendronic Acid, Denosumab was slightly better in delaying SRE's. Denosumab also results in low calcium and can, rarely, destroy the jaw, so a dental check before and calcium monitoring after treatment are advised.
Updated August 2018