Blood test could guide treatment for kidney cancer

A common enzyme that is easily detected in blood may predict how well patients with advanced kidney cancer will respond to a specific treatment, according to physicians at Duke Cancer Institute, Durham, NC.

The finding, published online in the Journal of Clinical Oncology (Aug. 13, 2012), could lead to the first blood test to determine the best treatment for late-stage kidney cancer.

"Being able to direct these patients to a treatment we know will help them would be a major advancement in their care," said lead author Andrew Armstrong, MD, ScM. "At the same time, patients who would not benefit from the treatment would be spared from undergoing a drug regimen with potential side effects that could diminish their quality of life."

Dr. Armstrong and colleagues focused on lactate dehydrogenase (LDH) and analyzed the outcomes of 404 study participants, approximately half of whom received a standard therapy, interferon-alpha, and half who received temsirolimus (Torisel), a mammalian target of rapamycin (mTOR) inhibitor.

LDH levels had been measured at the start of the study for all participants. In their analysis, the authors found that patients with high LDH levels at the start of the study survived significantly longer on the mTOR inhibitor than they did on interferon-alpha. Median survival for patients with high LDH levels was 6.9 months on temsirolimus compared with 4.2 months for the high LDH level patients on the standard drug.

At 6 months, 53.7% of high LDH level patients taking temsirolimus were alive, compared with 39.5% taking interferon-alpha. Patient survival rates at 12 months were 34.3% for temsirolimus, versus 12.7% for interferon-alpha. Patients with low LDH at the start of the study showed little difference in survival based on the drug they received, with median survival of 11.7 months for the mTOR inhibitor patients compared with 10.4 months for those taking interferon-alpha.

"This is an exciting finding," Dr. Armstrong said. "In breast cancer, for example, we can test for HER-2 expression and offer effective treatments based on that. Having a similar biomarker for kidney cancer that could direct patients to the best therapies for their cancer would be a major step forward."

The study was funded by Pfizer, Inc., and Dr. Armstrong and one of his co-authors receive speaking fees and research support from Pfizer and Novartis.

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