How less can be more when treating some kidney cancers

A new Mayo Clinic study suggests that removing the entire kidney from younger patients with small kidney tumours may lead to decreased overall survival compared with an operation that removes the tumour but leaves the kidney intact. The study will be published in the February issue of the Journal of Urology.

Radical nephrectomy is a surgical procedure to remove the entire kidney along with the adrenal gland that sits atop the kidney and adjacent lymph nodes. In a partial nephrectomy, only the tumour is removed, sparing the surrounding normal kidney tissue.

"For patients with small kidney tumours, removal of the entire kidney may be associated with long-term consequences that we did not previously recognize when compared to removal of just the tumour," says the study's lead author, R. Houston Thompson, M.D., a Mayo Clinic urologist currently serving a fellowship at Memorial Sloan-Kettering Cancer Centre. "Recent evidence suggests that there is a graded impact on survival based on declining overall kidney function. So as kidney function declines, the risk of heart attacks and heart-related events goes up, and consequently the risk of death from these events goes up."

In this retrospective study, the research team reviewed the cases of 648 Mayo Clinic patients who underwent either a partial or radical nephrectomy for a kidney tumour 4 centimetres or smaller. In the 327 patients younger than 65 years of age, radical nephrectomy was significantly associated with death from any cause when compared with partial nephrectomy.

Ten-year overall survival rates were 82 percent for patients treated with a radical nephrectomy and 93 percent for patients treated with a partial nephrectomy. "We know the survival from cancer with partial nephrectomy or radical nephrectomy for patients with these small masses is excellent," says Michael Blute, M.D., a Mayo Clinic urologist and senior author of the study. "Urologic surgeons need to consider long-term health consequences for patients with small renal mass undergoing complete nephrectomy."

According to Dr. Thompson, less than 25 percent of patients who are treated surgically for small kidney tumours undergo a partial nephrectomy in the United States. "The fact that this is being performed in less than a quarter of cases raises a quality of care concern," he says, adding that more study is needed.

(Source: Journal of Urology: Joel Streed: Mayo Clinic: January 2008)