Encouraging prostate cancer studies

Press, 26 April 1984, Page 13

Encouraging prostate cancer studies

NZPA-Reuter Daytona Beach Florida Canadian scientists have developed an experimental treatment for prostate cancer, ' the second biggest cause of cancer death in men, according to Dr Ferdnand Labrie, of Laval University in Quebec.

He said the treatment, which halts the production of hormones that “feed” the tumour, was soon to be tested in the United States and had the potential to reduce prostate cancer deaths “tenfold.” The American Cancer Society estimates there will be 80,000 new cases of prostate cancer in the United States this year. It was traditionally treated by castration to eliminate the hor-rnone-producing testes.

Current treatment involves the use of drugs to block the production of testosterone, a method called “medical castration.”

However, Dr Labrie told a science writers’ seminar at Daytona Beach, Florida,, neither surgical nor “medical” castration was totally successful in eliminating the hormones feeding the tumours.

“If vou can remove the

male hormones completely, the tumour reduces dramatically,” Dr Labrie said.

He said that castration was not completely successful because other hormones, androgens, were still produced by the brain to feed the tumour.

This was significant, Dr Labrie said, because exposure to low levels of androgens apparently changed the cancer cells into ones “which show no or poor response to any therapy.” By adding a “pure antiandrogen” which inhibits the production of adrenal androgens to the traditional treatment, eliminating all the hormones, “a positive objective response has been observed in all patients,” said Dr Labrie.

He said that in his experiment, which involved only 105 patients, the death rate was 3.3 per cent after 18 months, compared with a 35 per cent rate for traditional treatment.

Dr Bruce Chabner, of the United States National Cancer Institute, cautioned that the Canadian work was an initial experiment and more work would have to be done before it was approved for use in the general population.