Partial Nephrectomy Linked to Improved OS in T1a RCC

Patients with small renal cell carcinoma (RCC) tumors classified as T1a had improved overall survival (OS) when receiving partial nephrectomy compared with radical nephrectomy, according to a recent study. However, survival advantages diminished in patients with T1b/T2 tumors, and no survival advantage was seen in patients 75 years and older.

Based on these results, “the choice of surgical approach in patients with larger tumors should be driven by a thorough discussion of individualized risks and benefits,” wrote researchers led by Benjamin T. Ristau, MD, MHA, of Fox Chase Cancer Center in Philadelphia.

Ristau and colleagues conducted this study to gain more information about possible survival advantages associated with partial nephrectomy across all patients with small renal masses.

The study included 212,016 patients from the National Cancer Database with T1 and T2 RCC tumors who underwent either radical (59.7%) or partial (40.3%) nephrectomy. Among patients with T1a tumors and T1b/T2 tumors, 59.7% and 18.8% underwent partial nephrectomy, respectively.

Frequency of partial nephrectomy significantly increased from 2004–2014 for both tumor types. For T1a tumors, frequency increased from 40.6%–71.4% and for T1b/T2 tumors it increased from 8.4%–26.5%; P < .01).

Patients with T1a tumors were six times more likely to undergo partial nephrectomy (overall response [OR], 6.43; 95% CI, 6.09–6.79). In contrast, patients with high-grade disease (OR = 7.5) and sarcomatoid histology (OR = 0.56) were less likely to undergo a partial nephrectomy.

In all, OS was increased in patients who underwent partial nephrectomy for those with T1 and T1b/T2 tumors. The 5-year adjusted OS for T1a tumors was 89.6% for partial nephrectomy and 85.1% for radical nephrectomy (P < .01). For T1b/T2 tumors, the 5-year adjusted OS was 82.5% for partial nephrectomy and 80.8% for radical nephrectomy (P = .01).

The researchers noted that the differences seen here were only 4.5% and 1.7%, respectively.

“These small absolute differences, coupled with an inability to control completely for all confounders, highlight the nuance associated with surgical decision making in patients with localized RCC,” the researchers wrote.

Partial nephrectomy was associated with a significantly improved OS compared with radical nephrectomy for T1a tumors (hazard ratio [HR], 0.73; 95% CI, 0.70–0.75). The improvement in OS was also seen in T1b/T2 tumors but the benefit was smaller (HR, 0.88; 95% CI, 0.83–0.94).

The benefit of partial nephrectomy on OS decreased as age and time from diagnosis increased. No advantage for partial nephrectomy was seen in patients aged 75 or older at 5 or more years after diagnosis.

Commenting on the results of the study, Edward M. Messing, MD, FACS, professor of urology, oncology, and pathology at the University of Rochester School of Medicine and Dentistry, said the single most important takeaway is the recognition that even for larger renal masses, T1b to T2, and certainly for smaller renal masses, partial nephrectomy has become a standard of care.

“Part of this is that technically, people are a lot better at performing partial nephrectomies and can do more of them now,” Messing said.

However, he also noted that despite this trend, only Level 1 evidence in this area indicates a better outcome for radical nephrectomy.

This study, which used data from a large database, includes selection bias for partial nephrectomy to be done in younger and healthier patients with smaller tumors.

“You need a randomized study to really address the issue,” Messing said. “In the absence of that there are too many potential biases.”

Messing noted that the Southwest Oncology Group is currently trying to organize a randomized trial to look at partial compared with radical nephrectomies in this patient population, but when and if that trial will be approved is unknown.