What are the reported outcomes of partial nephrectomy nephron-sparing surgery (NSS)?

Updated: Apr 01, 2019
  • Author: Reza Ghavamian, MD; Chief Editor: Bradley Fields Schwartz, DO, FACS  more...
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Answer

Nephron-sparing surgery (NSS) is now associated with improved technical success rates and long-term disease-free survival rates comparable to radical nephrectomy, especially in low-stage disease. Excluding hereditary renal tumors, the overall risk of local recurrence in modern partial nephrectomy series is 4-6%. Local recurrence rates are reported to be higher in patients with suspected disease (6.6%) versus incidental disease (1.1%). Incidental tumors are of lower size, grade, and stage. [8]

Local recurrence after NSS represents, in part, growth of multifocal renal cell carcinoma (RCC) and not incompletely resected tumor. In a recent study of multifocality in RCC, the incidence rate of true unknown multifocality (at the time of surgery) was 6%, corresponding roughly to the local recurrence rates in the studies cited above. [9] The inherent risk of multifocality dictates a thorough inspection of the entire surface of the kidney at the time of operation. Certain pathologic patterns raise suspicion of multifocality, namely papillary RCC or mixed cell histological pattern.

NSS for RCC can achieve long-term tumor control, especially in the setting of a primary tumor smaller than 4 cm. In a recent study of 76 patients who underwent NSS, only 3 patients developed metastatic disease at a mean follow-up of 75 months. [10] Of the 51 patients who had a normal contralateral kidney, tumors were generally small and 49 patients had pathologic T1 or T2 tumors. Review of NSS data from 2 large centers reveals a 5-year cause-specific survival rate that approaches 90-95% for pathologic stage I RCC. [11, 3] As the pathologic stage of the renal lesion is increased, the risk of local recurrence and metastatic disease also increases.

Recently, several valuable reports regarding long-term follow-up and efficacy of this treatment modality were published. These recent, important, long-term studies on the efficacy of NSS serve to lead the way to expanding indications for NSS and are the first step in defining the new criterion standard for the treatment of RCC in appropriately selected patients with low-stage lesions of the appropriate size. [6, 11, 3]

To determine the clinical significance of early incidental detection of renal masses, one study compared patients who presented with one of the classic symptoms of RCC or subsequent metastases with patients who were asymptomatic in whom lesions were incidentally detected. [12]

From a large series of 633 patients, those with incidentally detected tumors had a significantly higher 5-year survival rate than those with symptomatic lesions (85.3% vs 62.5%). [12] The local and distant recurrence rates were also higher for symptomatic lesions. These findings correlate with a previous study by Licht et al on the results of NSS in incidental versus suspected RCC, in which the local recurrence rates were significantly lower (1% vs 6%) in the incidental group. [8] The 5-year cancer-specific survival rates were 94% versus 83% for incidental and suspected RCC, respectively. The higher survival rates in this series could be due to selection bias for NSS based on lower pathologic stage and size of the tumors. Nevertheless, the pattern is comparable.

Given that incidental tumors were of significantly lower grade and stage, current study, along with the increased detection of incidental renal tumors on cross-sectional imaging, serves to strengthen the place of NSS in the management of these lesions.

The Cleveland Clinic Group recently presented long-term results of partial nephrectomy for localized RCC with a minimum follow-up of 10 years. [6] This study of 107 patients revealed cancer-specific survival rates of 88.2% and 73% at 5 and 10 years, respectively. The study period dated back before 1988 and before the widespread use of cross-sectional imaging. The 10-year and 15-year local recurrence-free survival rates were 94% and 92%, respectively. The fact that 68% of patients were symptomatic at presentation, 31% had stage pT2 or higher tumors, and 90% had NSS for an imperative indication makes this study remarkable and adds more credence to NSS as a viable surgical option.

Nevertheless, the overall 10-year cancer-specific survival rate was 80%. The isolated local recurrence rate was 4%. When considering tumors smaller than 4 cm, the cancer-specific survival rate at 5 and 10 years was 98% and 92%, respectively. The cancer-specific survival rate was 100% for tumors smaller than 4 cm and a normal contralateral kidney, and no recurrences occurred.

Another recent large study evaluated the long-term efficacy of NSS using an analysis based on the new 1997 tumor, node, metastasis (TNM) staging system. [3] Patients who underwent a partial nephrectomy were compared to a group of patients who underwent radical nephrectomy and were matched in terms of age, sex, stage distribution, and follow-up time (mean 57 mo and 55 mo, respectively). The overall cancer-specific survival rates were 91.2% and 98% for radical nephrectomy and NSS patients, respectively, treated during the same time. The local recurrence rate was 2.7%.

When considering pT1 lesions with the 1997 TNM criteria, tumors larger than 4 cm but smaller than 7 cm fared just as well as tumors smaller than 4 cm treated by NSS (100% survival rate). The survival rates of the patients with a 1997 pT1 lesion and a normal contralateral kidney did not differ, regardless of whether NSS or radical nephrectomy was performed (100% vs 97.5%). Partial nephrectomy was clearly less effective than radical nephrectomy when performed for lesions larger than 7 cm. Therefore, this study expands on the idea set forth by earlier studies that set the limit of tumor size at 4 cm or smaller, demonstrating the efficacy of NSS for lesions smaller than 7 cm.

Lau et al from the Mayo Clinic recently compared radical nephrectomy and NSS in the setting of a unilateral RCC and a normal contralateral kidney for the treatment of RCC. [11] In each cohort, 164 patients were matched optimally according to grade, stage, size, age, sex, and year of surgery. Overall median follow-up time was 3.8 ± 5.3 years. The cancer-specific survival rates between NSS and radical nephrectomy at 5, 10, and 15 years (98%, 98%, and 91% and 98%, 96%, and 96%, respectively) did not significantly differ. These results support an earlier matched cohort from the authors' institution that revealed similar cancer-specific outcome between NSS and radical nephrectomy for low-stage (< 4 cm) low-grade tumors. The local recurrence rate was only 2%, and that of contralateral recurrence was only 1%.

These 3 recent reports from 3 institutions at the forefront of the surgical treatment of RCC provide reassuring evidence on the efficacy of NSS. The survival data are comparable to earlier reports with shorter follow-up. The risk of local tumor recurrence, a concern after NSS, was 2-4%. This is in the low end of the range previously reported in the literature (0-10%) and could be attributable to incidental detection of low-grade low-stage tumors in the contemporary series. Likewise, the risk of multicentricity could conceivably be lower, an argument in favor of NSS in the current era. The risk of contralateral recurrence was low (1%). In a large study of 1213 patients who underwent radical nephrectomy, Dechet et al found this rate to be higher (4%), which could be attributable to larger higher-stage tumors in that historical review. [13]

Certain clinicopathologic features can predict outcome after NSS. A recent study found that patients with clear-cell RCC had a significantly worse cancer-specific survival rate than patients with papillary and chromophobe RCC. [14] The cancer-specific survival rates at 5 and 10 years were 94.4% and 91.5% for clear-cell RCC, respectively, and 99% for both papillary and chromophobe carcinoma. Tumor stage and grade were significantly associated with outcome in the clear-cell group.


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