By THOMAS M. BURTON
Staff Reporter of THE WALL STREET JOURNAL

Thousands of men with advanced prostate cancer are worried that the recall of an herbal supplement could cost them years off their lives.

The supplement, PC-Spes, is a blend of Chinese herbs in capsule form that is often recommended by oncologists when traditional prostate-cancer treatments fail. Last month, the California Department of Health Services, working with the U.S. Food and Drug Administration, ordered a nationwide recall of PC-Spes because of possible contamination, requiring distributors to alert customers and return bottles to the manufacturer.

As many as 10,000 American men with advanced prostate cancer had been taking PC-Spes, and many of them are convinced it is the reason they are alive and relatively healthy. "We're all concerned because we're going to be dead pretty soon if we don't get this product back," says Carl Spangler, a 64-year-old graphic designer in Fredericksburg, Va., who began taking PC-Spes four years ago, after his prostate cancer metastasized into his stomach, kidneys and chest.

California health authorities ordered the recall after some bottles of PC-Spes were found to contain traces of warfarin, a prescription blood-thinning drug. State health officials say they ordered testing and analysis of the herbal product after discussions with the Orange County district attorney's office about herbal and other prostate-cancer remedies sold without prescription.

The case is a vivid illustration of gaps in the regulation of herbal products, an estimated $4.2 billion industry in the U.S. last year. The FDA oversees manufacturing of herbal supplements, requiring that they be safe and permitting limited general health claims. But unlike makers of prescription drugs, makers of supplements don't have to adhere to as rigorous manufacturing requirements or submit results of clinical trials to the FDA.

"There's no doubt that a manufacturer of dietary supplements is not subject to the same degree of scrutiny as a drug manufacturer," says David Horowitz, acting compliance director of the FDA's center for drugs. Barre Rorabaugh, chief operations officer for the manufacturer of PC-Spes, closely held BotanicLab of Brea, Calif., concedes, "We don't have complete control of the supply chain.

"The herbal product has fairly wide acceptance in the medical community. "Medical oncologists and urologists are split down the middle" about PC-Spes, says Charles Myers, director of the American Institute for Diseases of the Prostate, based in Charlottesville, Va., and the former director of the cancer center at the University of Virginia. "We all see impressive activity [against cancer] with PC-Spes," he says.

PC-Spes has received considerable acceptance among oncologists who treat a lot of prostate-cancer patients, Dr. Myers says. Oncologists who treat prostate cancer only occasionally tend to be more skeptical, he says. Usage of it has soared despite a number of serious side effects, ranging from libido loss to blood clots.

BotanicLab sells the capsules by mail order and through a small network of direct distributors (the supplement isn't readily available from non-U.S. sources). It says it doesn't believe its product has been contaminated with warfarin. The substance authorities detected could be one of a number of chemicals, called phytocoumarins, that occur naturally in some plants used as ingredients in PC-Spes, the company says. BotanicLab says it has hired an outside laboratory to conduct a new round of tests, and California officials say they are willing to review the new results.

Still, the apparent presence of warfarin is a startling coincidence: Many doctors prescribe warfarin for patients taking PC-Spes to counteract the possibility of blood clots. In e-mail discussion groups of PC-Spes users, there is no shortage of theories as to how contamination of one with the other could have occurred. BotanicLab's Mr. Rorabaugh acknowledges that sabotage is one possibility and says the company hasn't ruled out a scenario in which a raw-materials processor in China that also processes pharmaceuticals might have been to blame.

Aaron E. Katz, associate professor of clinical urology at Columbia University, in New York, says the recall is "anxiety-provoking for me, and for patients." The product "delayed disease progression and lowered patients' PSA," he says, referring to prostate specific antigen, a blood marker that generally tracks the progress of prostate cancer. Studies have shown PC-Spes sharply lowers the PSA in many men, which may lengthen life, although no scientific studies prove this.

Dr. Myers, of the prostate-diseases institute, calls PC-Spes "probably the most active agent," along with chemotherapy, for treating prostate cancer in patients who no longer get results from conventional hormone-blocking drugs, such as Lupron and Casodex, which impede prostate-cancer growth. It is estimated that 75% or more of the patients who were taking PC-Spes were in this category. In Portland, Ore., Fulton L. Saier, a physician and prostate-cancer patient, predicts the recall of PC-Spes "will potentially cause the death of thousands of men.

"Mr. Spangler, the graphics designer, doesn't want to try chemotherapy. "I don't need to come to a hospital and lose my hair," he says. Four years ago, he says, he was "a sick cookie": His PSA was nearly 3,000, an alarming level. With PC-Spes, it fell rapidly to below 1. "He is free of all disease," says Dr. Myers.

Rocco Giove, a West Bend, Wis., pharmacist, is in even more dire straits. After conventional prostate-cancer treatments failed two years ago, he started taking PC-Spes and has survived with a low PSA score. Now, he has run out of PC-Spes, and the blood marker has risen above 500, suggesting the disease is recurring. "I'm dying, and apparently bureaucracy couldn't care less," he says.

Write to Thomas M. Burton at tom.burton@wsj.com