Test may help detect prostate cancer recurrence

A new prognostic test may help determine whether a patient with prostate cancer will have a recurrence of the disease, even if surrounding lymph nodes initially appear negative for cancer, according to a study from the Keck School of Medicine at the University of Southern California, Los Angeles.

The test appears to be "better than anything else we know of for predicting recurrence," said lead author Richard Cote, MD, whose findings were published recently in the Journal of Clinical Oncology (2006; 24:2735-42).

Dr. Cote and colleagues examined 3,914 lymph nodes from 180 patients who were staged as having lymph nodes negative for cancer based on standardized histologic evaluation. The lymph nodes were then evaluated for occult metastases using new specific immunohistochemistry tests that can detect cancer on a cell-by-cell level.

The new analysis checks for cells that react with antibodies to cytokeratins and PSA. The team's testing found occult tumor cells in the lymph nodes of 24 of the patients whose lymph nodes previously had been diagnosed as cancer-free. The researchers then compared cancer recurrence and survival in patients with the hidden tumor cells and patients without the cells. The presence of occult tumor cells was associated with increased prostate cancer recurrence and decreased survival.

"The outcome for patients with occult tumor cells was similar to those who were identified as having positive lymph nodes at the time of the surgery," Dr. Cote said.