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New test improves predictions of prostate cancer recurrence

A new prognostic test can help determine whether a prostate cancer patient will go on to have a recurrence of the disease, even if surrounding lymph nodes initially appear negative for cancer, according to a study by USC researchers.

The study, “Detection of Occult Lymph Node Metastases in Patients with Local Advanced (pT3) Node-Negative Prostate Cancer” was published in the June issue of the Journal of Clinical Oncology.

Prostate cancer is the most common non-skin cancer in America, according to the Prostate Cancer Foundation. One in six American men will be diagnosed with prostate cancer, making men 35 percent more likely to be diagnosed with prostate cancer than women are to be diagnosed with breast cancer.

“Thanks to greater awareness, as well as increased and improved screening, we see men increasingly diagnosed with prostate cancer in its early stages,” said Richard Cote, professor of pathology and urology at the Keck School of Medicine. “Most of these patients will do very well and will not require treatment beyond surgery or radiation therapy to cure their disease.”

But a proportion of these patients go on to have metastases of the prostate cancer later, even when the lymph nodes removed at the time of the cancer surgery appeared negative for cancer, he noted.

Cote and his colleagues looked at 3,914 lymph nodes from 180 patients who were staged as having lymph nodes negative for cancer based on standardized histologic evaluation under a microscope. The lymph nodes were then evaluated for occult (hidden) metastases using immunohistochemistry that checked for cells reacting with antibodies to cytokeratins and PSA. The test found occult tumor cells in the lymph nodes of 24 of the patients.The study compared recurrence and survival in those patients with occult tumor cells versus those without the cells.

The presence of occult tumor cells was associated with increased recurrence and decreased survival. In fact, “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,” said Cote.

The test used to detect the occult tumor cells is more sensitive than any clinical, pathologic or radiographic techniques, said Cote.

“We have shown that occult tumor spread in lymph nodes is a significant predictor of disease recurrence,” he said.

He went on to say, “Once surgery is performed, the primary form of treatment is adjuvant systemic therapy. In patients with no evidence of metastasis, success of such therapy is assumed to be due to killing of occult tumor cells before it becomes clinically evident. Therefore, the ability to detect occult metastasis is pivotal to identification of patients who would most benefit from systemic therapy and also identify patients who may be spared from unnecessary therapy.”

The test, developed at USC, “appears to be a very powerful test and better than anything else we know of for predicting recurrence,” said Cote. Current trials are also using the test to find occult metastases in lymph nodes and bone marrow for breast and lung cancers.

Vincenzo Pagliarulo, Debra Hawkes, Frank Brands, Susan Groshen, Jie Cai, John P. Stein, Gary Lieskovsky, Donald G. Skinner, Richard J. Cote, “Detection of Occult Lymph Node Metastases in Patients with Locally Advanced (pT3) Node Negative Prostate Cancer,” Journal of Clinical Oncology, 24: 2735-2741, 2006.

New test improves predictions of prostate cancer recurrence

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