PROSTATE CANCER: WHY HORMONES DON’T CURE

Why not? Because prostate cancer, scientists have learned, is “heterogeneous,” a cellular melting pot. It’s a bunch of different cells mixed up together—so a drug or hormone treatment that targets one kind of cell, for instance, won’t have any effect against another variety. The cancer is made up of many different kinds of cells, and some of them have learned to be resistant, to grow in the absence of androgens, or male hormones. These are called androgen-independent, or -insensitive cells.

For years, scientists have been working to understand why hormonal treatment eventually fails—why some cancer cells seem to kick in and grow with such vengeance. “There’s probably no area of cancer therapy where we’ve got as many good options as we do for treating the hormonally responsive element of prostate cancer,” says a Johns Hopkins cancer researcher. “In sharp contrast, we have almost nothing that has proved very useful in managing the hormonally independent portion of the cancer.”

When a man starts hormone therapy, the early results are successful and highly encouraging: The tumor shrinks, PSA levels drop in the blood, and the patient feels better. But in the prostate, only the hormone-dependent cancer cells have been affected. The rest, the cancer cells that have nothing to do with hormones, go on about their merry, proliferative business, oblivious to the hormonal war being fought just cells away.

Scientists believe that these androgen-independent cells probably inhabit the prostate for years; they don’t just suddenly appear one day after the cancer is diagnosed. And so to do battle with them, many scientists feel, in the future hormone therapy must be combined with something else—chemotherapy, drugs targeted specifically at these androgen-independent cells. Today, however, effective treatment along these lines is not yet possible in men, and is only under experimental study.

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