The Morning Journal (Lorain, OH)
After prostate removal, where does PSA come from?
DEAR DR. ROACH»
Some 20 years ago, as I was turning 50, a biopsy confirmed prostate cancer. I elected to deal with that through surgery, a radical perineal prostatectomy.
For the following
10 years, follow-up blood tests came back showing PSA at “less than 0.1,” which I interpreted to mean levels below the detectable limit. About 10 years ago the lab announced that they had improved their methods and would henceforth report PSA in blood as low as 0.01. Since then, my lab reports for PSA have been in the 0.02-0.04 range. Are there tissues that are not removed during a radical prostatectomy that could produce these low levels of PSA? — D.A.S.
ANSWER» The term “prostate-specific antigen” isn’t exactly correct, because there are other cells in the body that produce PSA at very low levels. Urethral glands, salivary glands, normal breast tissue and some cancers besides prostate can, too.
When a PSA level that was previously undetectable after treatment such as surgery starts rising, it is almost always due to recurrence of cancer. However, this doesn’t seem to be the case for you. I suspect the very low levels you see now are either due to a very small amount of normal prostate tissue left after surgery or other tissues making PSA. Levels below 0.1 ng/mL are of uncertain significance, and the fact that they have stayed low for 10 or more years is good evidence there has been no recurrence of cancer.
DEAR DR. ROACH » In 1976 I lost a lung to cancer. I have enjoyed my life and never had a problem. Recently, I fell on the golf course, and landed on my chest on the good lung side. When I hit the ground, I heard a loud crack. I had an X-ray that day, and was so happy the X-ray showed no broken bones. It did show two or three “calcium spots” in the remaining lung.
Over the years I have had numerous X-rays, and they have all been clear. My doctor didn’t seem concerned. I remember having pneumonia as a kid, but that was 75 years ago. Can you explain where these deposits come from? Should I be concerned? — S.C.A.
ANSWER » Calcium in the lung, most commonly a calcified pulmonary nodule, has a long list of possible causes. Previous in- fection, tuberculosis and fungal infections commonly leave behind calcified nodules. Benign tu- mors are other causes. If the calcium spots are small (less than 5 mm), they are rarely anything to worry about. However, in a person with a history of lung cancer, a followup chest X-ray or CT scan would be prudent. Your risk of developing another cancer almost 35 years later is small but not zero.