Long-term renal functional outcomes of minimally invasive partial nephrectomy for renal cell carcinoma.

OBJECTIVE

Preservation of renal function is the major benefit of partial over radical nephrectomy. We evaluated patients undergoing minimally invasive partial nephrectomy (MIPN) to better understand factors predicting long-term renal function.

METHODS

We identified 358 patients who underwent MIPN for confirmed renal cell carcinoma between 1998 and 2011 with a serum creatinine level at least 1 year postoperatively. Exposure variables included demographic, clinical, and perioperative information. The primary outcome was clinically significant progression of chronic kidney disease (CKD) class, defined as estimated glomerular filtration rate (eGFR) decreasing from >60 to<60, from 30 to 60 to <30, or from 15 to 30 to<15. Bivariate and multivariate analyses were performed.

RESULTS

Median follow-up was 39 months. Only 7 patients had a solitary kidney. A total of 47 patients (13%) had CKD class progression. The estimates for remaining free of CKD class progression at 5, 7, and 10 years were 86.98%, 75.45%, and 53.54%, respectively. On multivariate analysis, lower preoperative eGFR (odds ratio [OR] = 0.97, 95% CI: 0.96-0.98), larger tumor size (OR = 1.22, 95% CI: 1.01-1.48), and longer ischemia time (OR = 1.03, 95% CI: 1.01-1.05) were associated with CKD class progression.

CONCLUSIONS

Clinically significant progression of CKD occurs in a minority of patients 5 years after MIPN, but in almost one-half, it occurs 10 years after surgery. Lower preoperative eGFR and larger tumor size are associated with greater incidence of CKD progression. Longer ischemia time, even when most patients had 2 kidneys and when controlling for other factors, nonetheless increased the risk of CKD progression, although this may be a marker of other unmeasured variables.