Test monitors prostate cancer chemotherapy effects

By Will Dunham

WASHINGTON, Feb 10 (Reuters) - A test that looks for tumor cells in the blood may make doctors better able to check whether chemotherapy is helping a prostate cancer patient, researchers reported on Tuesday.

The CellSearch test, made by Johnson & Johnson (JNJ.N) unit Veridex, works better than standard tests for men whose prostate cancer has spread, the researchers said in the journal Lancet Oncology.

The test counts the number of cancer cells that have broken away from the tumor and are circulating in the blood.

In a study involving 164 men, the researchers found that CellSearch helped them monitor the response to chemotherapy in patients who had prostate cancer that had spread and were not being helped by hormone therapy.

Hormone therapy aims to stop the body's production of testosterone or block hormones from getting into tumor cells.

They said it worked better than a standard test that looks at prostate specific antigen, or PSA, levels. PSA is a protein produced by the prostate, and levels may shoot up when prostate tumors grow or spread.

"It shows that the CTC (circulating tumor cells) counts can be used to help determine an individual's prognosis, particularly when the counts are high," Dr. Howard Scher of Memorial Sloan Kettering Cancer Center in New York, one of the researchers, said in a telephone interview.

"And it also helps in terms of understanding if the treatment is working," Scher added.