Cancer Free if PSA is 0?
Dear OncoLink "Ask The Experts,"
I had a radical prostatectomy approximately 12 years ago. My PSA level increased from 5.5 to 7.5 ng/mL over 3 months. My doctor stated that this means that I have metastatic cancer and he started hormone therapy with Lupron. It has been 3 mo. since I had the shot and a repeat PSA test was undetectable. Does this mean that I no longer have cancer?
Richard Whittington, MD, Associate Professor of Radiation Oncology at the University of Pennsylvania School of Medicine, responds:
I would make a distinction that his physician may disagree with, but I think is important. The PSA does not indicate metastatic prostate cancer, but rather recurrent prostate cancer. None of this information tells us where the tumor is at this time. The most likely area is in the pelvic region where the prostate was located, and this is not metastatic cancer, but a local recurrence. The main metastatic area is in a bone. A CT scan of the abdomen and the pelvis would look for any local recurrence, and a bone scan and probably a chest X-ray would look for metastatic disease.
The fact that the PSA is now 0 means that they are unable to detect any cancer cells. This is a very good sign, but it does not mean that he is cured. We know that most men treated with leuprolide will eventually have the tumor start to grow again. The fact is though that the lower the PSA goes, and the faster it gets there, the longer it is likely to take for the tumor to regrow. So this patient may never hear from the tumor again, which is the same as cure. If it does regrow, it may not do so for 5 or 10 years.
How long to stay on the hormone therapy, now that the disease is undetectable, is controversial. There are two schools of thought. One group says that you start the hormones and continue them forever, while the other says you can play oncologic Whack-a-mole. (People extrapolate theories from data on antibiotic resistance in bacteria. The two ways you make bacteria resistant to an antibiotic is to expose it for a long time to the antibiotic, or to give too short a course of antibiotics and then later repeat it). Nobody knows which approach is best when it comes to hormone therapy. There is an international randomized trial right now studying this very question. One group of patients gets leurprolide for a year, stops it, and then restarts when the PSA rises to 5.0. The other group gets it continuously. If there is a difference, it is likely small. One big downside to continuous hormonal treatment is that it is associated with osteoporosis and an increased risk of hip fracture, as well as a very small increase in the risk of heart attack.