New Prostate Cancer Tests Create Treatment Dilemmas : Part 2

by Food and Drug Administration (FDA)

(Page 2 of 2)

Making Sure

Doctors follow up an elevated PSA or positive DRE with more definitive testing. Some physicians employ transrectal ultrasound (TRUS), which uses a rectal probe that creates a video image of the prostate using harmless sound waves collected by a computer. TRUS helps the physician "map" uneven areas of firmness in the prostate, and it can help a doctor decide if a biopsy is needed. If so, the doctor will take tiny prostate tissue samples with a small-gauge needle, injected typically through the rectum. Another physician, a pathologist, then examines the samples under a microscope.

"No surgery or other anti-cancer therapy is done without first ensuring with a biopsy that a patient has cancer and not some other condition that can cause symptoms and other suspicious signs," says FDA's Robinowitz. Once cancer is diagnosed, other tests such as computerized tomography, lymph-node biopsies, and bone scans can determine if tumors have spread beyond the prostate.

For cancer confined to the prostate, opinions are split over what to do. Orthodox wisdom holds that cancer should be treated aggressively. With prostate cancer, this means removing the gland (radical prostatectomy) or bombarding it with radiation. Experts say these options may offer good prospects for curing the disease if exercised early enough. Treatment choice usually depends on what specialist the patient consults. Urologists tend to recommend surgery while oncologists generally advise radiation therapy.

Surgery may cause unpleasant adverse effects. Because radical prostatectomy can result in severing nerves and blood vessels related to sexual or bladder function, the operation in the past has left virtually all patients impotent, incontinent, or both. That is changing, however, thanks to pioneering research done in the 1980s by Patrick Walsh, M.D., urology chairman at Johns Hopkins University Hospital. His "nerve-sparing" surgical technique, which increasing numbers of doctors are adopting, now allows many men to preserve erectile functions. Walsh says his patients under age 50 have about a 90 percent chance of regaining potency, but that number drops to 25 percent for patients in their 70s.

Radiation therapy also has adverse effects, including impotence in about 40 to 50 percent of patients.

For older men with early-stage prostate cancer, a number of physicians are dispensing a different kind of advice: Wait and see.

Doctors clearly are divided on its merits, but this "watchful waiting" philosophy got a boost by a 1994 report in the New England Journal of Medicine. The study analyzed case records of 828 prostate cancer patients treated conservatively (watchful waiting or hormone treatments but no surgery or radiation therapy). It found that 10 years after diagnosis, 87 percent of those with slow-growing, localized prostate tumors still were alive. Of those diagnosed with more aggressive cancer, 34 percent remained alive at the 10-year mark. Supporters say watchful waiting is a practical alternative for men in their late 60s or older, whose lifespans may be limited by advanced age and serious ailments such as heart disease. If treated, these men could suffer the trauma and adverse effects of cancer therapy with little or no benefit.

Not all prostate cancer is equal. One type of tumor may lie dormant for years while another is virulent and deadly. Deciding whether to wait or act can be difficult because physicians often can't judge conclusively which tumors might spread. Size can give some indication. Another gauge, the Gleason system, identifies a tumor's growth potential based on its appearance under the microscope. The system distinguishes progressive grades of prostate cancer on a scale of 2 to 10. Clumped-together cancer cells with well-defined edges are less likely to grow rapidly and are given a low Gleason number. Cells distributed randomly with uneven edges are more apt to spread and receive a high Gleason number.

Also important is "staging" — a predictor of how extensively the disease has grown within or beyond the prostate. This ranges from stage A, where the tumor is still microscopic and confined, to stage D, where cancer has spread to the lymph nodes or to other organs outside the prostate. The lower the staging, the more likely the cancer can be cured. Stage D tumors are rarely curable. The ideal watchful waiting candidate is a man with a low Gleason score and a stage A or B tumor.

Prostate tumors are fueled by male hormones called androgens. Advanced prostate cancer is usually treated with therapy that reduces androgen levels — such as testicle removal or drug/hormone therapy.

Though prostate cancer research has yielded significant advancements in the last decade, there's still a long way to go, says FDA's Robinowitz. "The dilemmas [of treatment] are due to the power of the cancer and the limits to our current knowledge and therapies," he says. "New tests [such as PSA] may be only partial solutions, but they are the best we can do for now."

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