In Kidney Cancer, Better Outcomes Demonstrated With Nephron-sparing Surgery

William C. Huang, MD

Patients with renal cell carcinoma have better outcomes when undergoing nephron-sparing surgery rather than radical nephrectomy, according to findings from national Surveillance, Epidemiology, and End Results (SEER) registry (2001-2009) data. William C. Huang, MD, of the New York University Langone Medical Center and colleagues noted that overall survival was better in patients who received surgical treatment than in those who received nonsurgical management. However, only nephron-sparing surgery was associated with a benefit in cancer-specific survival (adjusted hazard ratio, 0.47; 95% CI, 0.31-0.69; P <.001).

Surgery continues to be the most common treatment in the management of small kidney cancers, with nephron-sparing surgery exceeding radical nephrectomy. The researchers noted that in elderly patients or those with limited life expectancy, nonsurgical management is a reasonable treatment strategy. Huang said in a release that “although our findings support nonsurgical management as an acceptable treatment option for small kidney tumors in elderly patients or those with limited life expectancy, it appears that nonsurgical management of small kidney cancers remains uncommon and stable over time.” He added that heightened awareness of outcomes from studies such as this may increase the use of nonsurgical management.

In the population-based cohort study, SEER cancer registry data linked to Medicare claims were used to identify patients 66 years or older with a diagnosis of primary renal-cortical tumor (<4 cm). Analysis was performed between February 1, 2014, and December 31, 2014. The likelihood of receiving no surgery versus surgical intervention was analyzed as a function of demographic and disease characteristics, as well as the relationships between treatment approach and overall and cancer-specific survival.

According to their findings, published in JAMA Surgery, radical nephrectomy is no longer the treatment of choice for small kidney cancers. “Expert guidelines for the management of small renal masses, such as those published by the American Urological Association in 2009, appear to have bolstered the paradigm shift away from radical nephrectomy toward nephron-sparing options for such tumors,” said Huang.

The same practice guidelines also offer ablation and surveillance as alternative treatment options for small kidney masses, noted Huang. Partial nephrectomy and ablation were combined and classified as nephron-sparing surgery and nonsurgical management was defined as the absence of any claim for one of these procedures in the first 6 months following diagnosis. During the study period, 3709 of the patients (61.9%) who underwent surgery had radical nephrectomy, and 2285 patients (38.1%) had a nephron-sparing procedure.

Out of a total of 6664 patients, 90.0% (5994) underwent surgery; 10% (670) of patients were managed nonsurgically. The data revealed that the use of radical nephrectomy decreased from 69% to 42.5%. During the same time, nephron-sparing surgery (partial nephrectomy and ablation) increased from 21.5% to 49.0%. The proportion of patients who chose not to undergo surgery remained stable, reported the investigators. During a median follow-up of 63 months (interquartile range, 43-89 months), 2119 patients (31.8%) died, including 293 (4.4%) from kidney cancer.

“Our findings underscore the importance of competing causes of mortality in this population: 38.1% of patients died during the study period, but only 4.4% of patients died from kidney cancer,” said Huang.

Differences in overall survival may reflect patient selection rather than a direct benefit of surgery, as highlighted by the greater risk of mortality observed soon after diagnosis in the cohort managed non-surgically, he said.

“Survival outcomes of partial nephrectomy appear to be at least equivalent and potentially superior in the short-term (median, 63 months) compared with radical nephrectomy,” according to Huang. “Practically, the support for partial nephrectomy is bolstered both by patients hoping to preserve as much kidney as possible to prevent the burdens of hemodialysis and the urologist who has benefited from improvements in surgical experience.”

With controls for demographic and disease characteristics as well as comorbid conditions, patients whose care was managed non-surgically were more likely to be older, male, and nonwhite and to reside in the Western United States. Hypertension was associated with a greater likelihood of being treated surgically, and a prior non-kidney cancer diagnosis was associated with a greater likelihood of nonsurgical management, said Huang.

Joshua J. Meeks, MD, PhD

With a median follow-up of 57 months (inter-quartile range, 43-89 months), 136 patients (20.3%) who initially received nonsurgical treatment underwent surgery more than 6 months after diagnosis.

In an accompanying editorial titled, Joshua J. Meeks, MD, PhD, department of urology, Feinberg School of Medicine, Northwestern University, Chicago, IL, said that “the authors establish partial nephrectomy as the new standard of treatment for small renal masses (SRMs) with the frequency of nephron-sparing surgery eclipsing that of radical nephrectomy in 2009.”

Meeks noted that despite an overall increase in surgery for SRMs, the survival for patients with kidney cancer has not changed. In this study, a consistent 10.0% of tumors were actively monitored and these tumors were more likely to occur, he said.

“In older and unhealthy patients with overall survival of only 57.5% at the completion of the study, it is unclear how many masses were identified by imaging but not biopsied and therefore potentially not identified by the SEER registry,” said Meeks.

“At some point,” he emphasized, “every metastatic cancer must have been an SRM. As we learn more about the molecular signature of renal cancer and the mutations that drive progression, we will likely be managing SRMs differently in the near future.”