Following recent clinical trial data from the European Organisation for Research and Treatment (EORTC) showing a survival benefit for patients with small kidney cancers treated with radical vs partial nephrectomy, an analysis using linked Surveillance, Epidemiology and End Results (SEER) and Medicare data found that treatment with partial rather than radical nephrectomy was associated with improved survival. Researchers at the University of Michigan in Ann Arbor noted that the EORTC study “had several notable limitations,” including accrual difficulties and premature closure, and “occurred in an era when most surgeons rarely performed partial nephrectomy. As such, many argue that the EORTC trial is not generalizable to contemporary practice.”
The Michigan researchers used “an instrumental variable approach to account for measured and unmeasured differences between treatment groups,” they reported. “By applying this technique to a population-based patient cohort, we can clarify the comparative effectiveness of partial vs radical nephrectomy in the treatment of patients with early-stage kidney cancer,” they wrote in Journal of the American Medical Association.
The study included 7,138 Medicare beneficiaries with clinical stage T1a kidney cancer treated from 1992 through 2007, 27% with partial and 73% with radical nephrectomy. “Patients treated with partial nephrectomy were younger, more often men, and resided in census tracts with higher levels of average income and education than those treated with radical nephrectomy,” the authors noted.
At a median follow-up of 62 months, 487 of the 1,925 (25.3%) of patients who had partial nephrectomy died, compared to 2,164 of the 5,213 (41.5%) of patients who had radical nephrectomy. “Kidney cancer was identified as the cause of death for 37 patients (1.9%) treated with partial nephrectomy and 222 patients (4.3%) treated with radical nephrectomy,” the researchers reported. “Based on a predicted survival difference of 15.5 percentage points at 8-year follow-up, 1 life would be saved for every 7 patients treated with partial rather than radical nephrectomy. Accordingly, our findings support partial nephrectomy as the preferred treatment option for the ever-expanding pool of patients with kidney tumors measuring 4 cm or smaller,” the researchers stated.
The authors noted that their own study also has limitations, such as being restricted to Medicare beneficiaries and the smallest kidney tumors (≤ 4 cm), so the findings may not be generalizable to younger patients and those with larger masses. They also pointed out that “partial nephrectomy remains a technically challenging operation with potentially significant complications (eg, hemorrhage, urinary fistula) that are seen less frequently with radical nephrectomy. This concern cannot be ignored when making treatment decisions,” they wrote.
“Indeed, the benefits of partial nephrectomy must always be weighed against the risk of acute surgical morbidity. In certain scenarios, some patients may be better served with an uncomplicated radical nephrectomy. Likewise, alternative treatment options, including active surveillance and ablative therapies, may be particularly prudent for patients in whom the benefits of surgical removal are less apparent.” ■
Tan HT, et al: JAMA 307:1629-1635, 2012.