Saving Kidney Tissue May Not Improve Survival in Renal Cancer

Undergoing nephron-sparing surgery (NSS) for small renal masses substantially reduced the risk of moderate renal dysfunction compared with radical nephrectomy, but not that of kidney failure, among patients enrolled in the EORTC 30904 trial. However, the reduced risk of moderate renal dysfunction associated with NSS did not result in improved overall survival.

The results of this analysis were published by Emelian N. Scosyrev, PhD, an epidemiologist and assistant professor of urology at the University of Rochester Medical Center, and colleagues in European Urology.

According to Scosyrev, when NSS was first available as a treatment for patients with small masses, its advantages and disadvantages relative to radical nephrectomy were not obvious.

“It was hypothesized that oncologic control with NSS was comparable to that of radical nephrectomy, but NSS would result in better preservation of the kidney function, leading to improved overall survival,” Scosyrev told Cancer Network.

However, based on the results of this analysis, patients who underwent radical nephrectomy developed moderate renal dysfunction based on the estimated glomerular filtration rates (eGFR) measurements, but that did not translate into a progressive condition.

In this analysis, the researchers looked at patients from the phase III international EORTC 30904 trial who were randomly assigned to radical nephrectomy (n = 273) or NSS (n = 268). Patients were examined for moderate renal dysfunction (eGFR < 60), advanced kidney disease (eGFR < 30), or kidney failure (eGFR < 15). Patients had a median follow-up of 6.7 years.

The results indicated that compared with radical nephrectomy, NSS can substantially reduce the risk of moderate renal dysfunction. At follow-up, 85.7% of patients who underwent nephrectomy had eGFR < 60 compared with 64.7% of patients who underwent NSS; eGFR < 30 occurred in 10% of patients who underwent nephrectomy compared with 6.3% of NSS. However, rates of kidney failure were similar for the two groups at about 1.5%.

In addition, the previous results of the EORTC 30904 trial showed that NSS was associated with a reduced overall survival among these patients compared with nephrectomy.

“Before results of EORTC 30904 became available, it was believed that moderate renal dysfunction resulting from surgery had the same prognostic implications for all-cause mortality as moderate renal dysfunction resulting from systemic medical illnesses, such as diabetes or hypertension,” said Scosyrev. “However, findings from EORTC 30904 clearly indicate that surgical and medical nephron loss have very different prognostic implications.”

According to Scosyrev, systemic medical illnesses typically have major direct effect on other vital organs in addition to the kidney, whereas nephrectomy targets the kidney alone, explaining why NSS does not improve overall survival. However, it is still unclear whether the procedure reduces survival.

“If NSS does in fact increase all-cause mortality in some patients, this may be related to [interference with the renin-angiotensin system], although this is very speculative,” Scosyrev said. “Although it can certainly be doubted whether NSS can decrease overall survival relative to radical nephrectomy, it is clear that it does not increase it, at least in patients similar to those enrolled in EORTC 30904.”

The researchers noted for patients with adequate kidney function at baseline, radical nephrectomy is a reasonable treatment option.

“It should definitely be the treatment of choice when NSS appears to be technically difficult or not entirely safe from the standpoint of oncologic control,” Scosyrev said.