Δευτέρα, 8 Μαΐου 2017

METASTATECTOMY EFFECTIVE FOR RENAL CANCER

researchers have discovered that surgery could more than double life expectancy for many patients with late-stage kidney cancer, giving them anywhere from 2 to almost 10 years more than they would have without the surgery. A paper published by Zaid et al in The Journal of Urology found a “clinically meaningful difference in survival” between patients with renal cell carcinoma who underwent metastasectomy and those who didn't.
“The research found patients who had surgery to remove metastases were about half as likely to have died from their metastatic disease at every point in time after diagnosis,” said Bradley Leibovich, MD, a Mayo Clinic urologist and the paper's senior author.
Dr. Leibovich said he had long seen anecdotal evidence that surgically removing metastases would result in a longer life expectancy. However, studies on the subject were not conclusive, because they did not sufficiently address selection bias, meaning patients with fewer growths or growths in areas that were easier to operate on were naturally chosen for surgery more often. Those types of patients often lived longer, too.
Study Findings
With the help of the center, Mayo urologists and other researchers analyzed previous studies. This meta-analysis looked at 8 studies of 2,267 patients with renal cell carcinoma. It found the total life expectancy for patients whose metastases weren't surgically removed was between 8 months and just over 2 years, but that jumped to 3 to 12 years for those who had the surgery.
“At the end of the day, we're trying to target patients who have an unfortunate diagnosis and trying to optimize the outcome,” said Harras Zaid, MD, a Mayo urologic oncology fellow and the paper's lead author.
“With a lot of cancers, we know there's a range of survival, but kidney cancer is notable for very significant variability in survival after finding spread of disease, with some patients dying much sooner and some living much longer than expected,” said Dr. Leibovich.
Dr. Zaid performed the meta-analysis with guidance from M. Hassan Murad, MD, a health services researcher in the Center for the Science of Health Care Delivery at Mayo and a coauthor. For their paper, they only chose “observational studies with a low to moderate risk of bias,” the researchers wrote, but the potential still existed.
Looking Ahead
Since the majority of the data analyzed in this study were published, immunotherapies and other drug therapies for kidney cancer have advanced considerably. The U.S. Food and Drug Administration approved the first drug for kidney cancer treatment in 1992, but there are more than 10 today, and most were approved in the past decade, according to the National Cancer Institute.
“Now that we have some better drugs for treating these patients, does our conclusion still hold true? We suspect that it will,” said Dr. Leibovich. “In people who haven't had complete removal of the metastases, drug therapy seems to benefit. But in patients who have that surgery, drug therapy doesn't seem to make a difference.” With one of their next studies, the team is evaluating the interaction of surgery and drugs to determine if the combination increases survival even more.
Dr. Leibovich said the concern is that, because there are myriad drug treatments available, patients may not be referred to surgeons, or medical oncologists may not consider surgery as an option. “Is that so bad if we have all these drugs? The answer is maybe yes, because the drugs, while they have improved survival, are not usually curative,” said Dr. Leibovich. “If they work for only a finite period, and if surgery can lengthen the time before we need to enter that period, then we think that's potentially additive to overall survival.”

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