New research concludes that removing just part of the kidney yields higher five-year survival rates than removing the entire kidney in patients with early-stage kidney cancer.
The authors of the study, published in the Journal of the American Medical Association (2012;307:1629-1635), note that although partial nephrectomy has been the preferred treatment, recent clinical trial data suggesting that full nephrectomy offers better patient outcomes has reopened the question of which therapy is in fact superior.
“We found that among patients who were candidates for either partial or radical nephrectomy, patients treated with partial nephrectomy seemed to have better survival long-term than patients treated with full nephrectomy,” said the study's lead author, Hung-Jui Tan, MD, a urology resident at the University of Michigan.
As to why earlier studies may have yielded contradictory evidence to these findings, he said, “Our study is better representative of more contemporary surgical practice with updated techniques and more contemporary patients, where the earlier study was more representative of a historical experience.”
In the past, partial nephrectomy was more often reserved for an unhealthy cohort of kidney cancer patients, including those with chronic kidney disease (CKD) or a solitary kidney, whereas now the technique is more commonly considered an option for all kidney cancer patients.
To avoid the selection bias of earlier trials, the researchers limited inclusion in this retrospective cohort study to patients who were candidates for full or partial nephrectomy and had early-stage cancers (i.e., tumors 4 cm or smaller) with localized disease and no evidence of regional metastasis, Dr. Tan said.
Among 7,138 patients diagnosed with incident kidney cancer between 1992 and 2007, 25% of those who had a partial nephrectomy died during a median follow-up of 62 months, compared with 42% of those who had a full nephrectomy, the researchers reported.
The rates of cancer-specific mortality were statistically equivalent between the two patient groups, showing that patients in both groups were equally likely to die of kidney cancer and that either procedure was equally likely to cure the cancer.
Improved survival rates among partial nephrectomy patients are likely because of the reduction in incidence of CKD, which is known to be associated with full kidney removal. But additional studies are needed to confirm those assumptions, Dr. Tan said.
“Our findings suggest that by judiciously expanding the use of partial nephrectomy, clinicians can optimize survival outcomes among patients seeking treatment for early-stage kidney cancer,” he and colleagues wrote.
The research was supported by funding from the Agency for Healthcare Research and Quality, the Edwin Beer Research Fellowship in Urology and Urology-Related Fields from the New York Academy of Medicine, and the University of Michigan Comprehensive Cancer Center. David C. Miller, MD, MPH, of the Department of Urology at the University of Michigan, was the senior author.
‘Best Epidemiologic, Outcomes Data’
Commenting on the study for this article, Walter Stadler, MD, the Fred C. Buffett Professor of Medicine and Director of the Genitourinary Program at the University of Chicago Medical Center, said that the research is relevant because the prespecified cohort included only patients with defined renal cancer, as opposed to other studies that looked at patient cohorts with renal masses and reached contradictory conclusions.
“This is the best epidemiologic and outcomes data that I'm aware of to support the survival benefit of partial nephrectomy in patients with small renal tumors,” he wrote in an e-mail message.
But full nephrectomies should not be ruled out as a treatment option in all patients with kidney cancer, he noted. Technical challenges and surgery risk are higher in partial versus radical nephrectomies, and these barriers increase with tumor size, he said.
“This research is relevant for the smaller tumors, but surgical expertise becomes a more important factor for larger tumors.”
For more advanced cancer and other situations where tumor location may increase the risk of acute morbidity or complications, radical nephrectomy may be preferred, Dr. Tan said.
“Ultimately the decision between a partial nephrectomy and a radical nephrectomy is between the patient and the physician.
“This study doesn't say that everybody should get a partial nephrectomy, but it does say that for patients who would be candidates for both, the increased use of this surgery may improve rates of survival for patients with kidney cancer.”
A slightly different version of this article appeared originally in Oncology Times, another newspaper published by Wolters Kluwer Health/Lippincott Williams & Wilkins.