A common enzyme that is easily detected in blood may predict how well patients with advanced kidney cancer will respond to a specific treatment.
In kidney cancer, elevated lactate dehydrogenase (LDH) levels were considered a risk factor for aggressive disease, signaling tumor progression. Recent studies suggest that elevated LDH may also indicate the activation of key genetic alterations that lead to cancer proliferation. One of these cancer gene pathways relies on a protein called mammalian target of rapamycin, or mTOR, and drugs that are mTOR inhibitors work to shut down the process.
Andrew Armstrong, MD, ScM, associate professor of medicine and surgery at Duke University Medical Center (Durham, NC, USA) and colleagues at Duke analyzed the outcomes of 404 study participants, approximately half of whom received a standard therapy, interferon-alpha, and half who received temsirolimus, a mTOR inhibitor, which has been approved by the US Food and Drug Administration to treat kidney cancer. LDH levels had been measured at the start of the study for all participants.
Patients with high LDH levels at the start of the study survived significantly longer on the mTOR inhibitor drug than they did on interferon-alpha. Median survival for patients with high LDH levels was 6.9 months on temsirolimus compared to 4.2 months for the high LDH level patients on the standard drug. At six months, 53.7% of high LDH level patients taking temsirolimus were alive, compared to 39.5% taking interferon-alpha. Patient survival rates at 12 months were 34.3 percent for temsirolimus, vs. 12.7% for interferon-alpha.
Prof. Armstrong, lead author of the study, said that the study statistically proves that LDH is a predictive biomarker for advanced renal cell carcinoma (RCC), but the results have to be validated before major practice changes take place.
"The advantage of LDH as a predictive and prognostic biomarker rests in its ease of collection, cost, and its routine assessment as part of routine medical care in patients with RCC," the authors wrote.
Duke University Medical Center