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As a senior manager at the Calgary company that makes popular SMART Boards, Ken Dreger is a no-nonsense, can-do type of guy.

He has taken the same approach to his battle with prostate cancer, and as a co-founder of the group ProstAid Warriors. “I'm not just going to sit back and die without a fight,” Mr. Dreger said. “My goal is to get to 65.”

He is 63 today.

Mr. Dreger was diagnosed with cancer in 2000, and underwent surgery to remove his prostate gland. Treatment failed, as it does for about one in five men.

He was prescribed androgen-deprivation therapy (ADT) to block the production of testosterone. These drugs are the last hope for patients whose cancer is spreading, but they cause chemical castration.

There were almost 300,000 prescriptions for ADT drugs in Canada last year, with sales in excess of $165-million, according IMS Health Canada, a private company that tracks prescription drug sales.

The most common form of ADT is using drugs called luteinizing hormone-releasing hormone (LHRH) agonists. They work by lowering levels of testosterone produced by the testicles. The big sellers include leuprolide (brand name Lupron) and goserelin (Zoladex). These drugs are injected by a physician or implanted under the skin every few months. Each treatment costs about $1,000.

When LHRH agonists are first given, they can cause a surge in testosterone production and intense bone pain, so patients often receive anti-androgens, which block the body's ability to use hormones like testosterone.

Anti-androgens can also be combined with LHRH agonists, or taken alone. The drugs, taken in daily pill form, include flutamide (Euflex) and bicalutamide (Casodex).

Another form of ADT are LHRH antagonists. They work in a similar manner to LHRH agonists but do not cause flare-ups of pain. However, the drug abarelix (Plenaxis) can trigger a life-threatening allergic reaction in some men, so it is used only when other forms of therapy are not tolerated.

Other treatment protocols call for the addition of drugs like finasteride (Proscar), which is usually used to treat benign forms of prostate enlargement, and cabergoline (Dostinex), a treatment for Parkinson's disease.

When the disease becomes too advanced and methods to block testosterone fail, patients turn to drugs like docetaxel (Taxotere), a form of chemotherapy. (Prostate cancer, unlike other cancers, is rarely treated with chemo.)

Mr. Dreger, who does extensive research and has even hired a famed U.S. prostate cancer specialist to oversee his treatment, has tried virtually all these approaches, and then some.

The only method he has forgone is surgical castration, which would be moot given the ADT treatment. He also takes a number of supplements that have been shown to bolster prostate health, along with other medications to treat the side effects of treatment. The supplements popular with advanced prostate cancer patients include pomegranate, vitamins C, E and D, selenium, folic acid and fish oils.

Jack Barkin, chief of urology at Humber River Regional Hospital in Toronto, said he believes that ADT drugs are properly prescribed but patients need to be conscious of the side effects.

Erectile dysfunction that accompanies chemical castration gets all the attention, but it is treatable, he said. “I can get a man an erection if that's his concern.” But the drugs also cause a loss in libido, and loss of interest in sex, so the mechanics aren't the issue.

ADT also increases the risk of cardiovascular disease and osteoporosis, so drugs are prescribed to lessen those impacts.

Most advanced prostate cancer patients take blood thinners such as warfarin (Coumadin) to stave off heart problems and biphosphonates such as zoledronic acid (Zometa) to help retain bone density.

“Patients,” Dr. Barkin said, “should not be reluctant to accept treatment because of side effects – we can treat those.”