Comparing eGFR Changes in Partial Nephrectomy (PN),Cryoablation (CA) and Radiofrequency Ablation (RFA)—A Single Centre Experience

Objective:

The effect of nephron-sparing surgery on estimated Glomerular Filtration Rate (eGFR) is unclear. Comparisons of baseline to post-operative creatinine ratios are well published, but as eGFR and corresponding chronic kidney disease (CKD) stage is a more accepted measure of renal function and relates to quality of life we postulate preference for this measurement.

Patients:

100 open partial nephrectomies (PN), 28 laparoscopic cryoablations (CA) and 14 percutaneous radiofrequency ablations (RFA) were compared from a prospective database. Estimated eGFR was calculated by the modified diet in renal disease formula. Changes in eGFR were calculated by the formula 100 × (B — A)/A where A = pre-operative eGFR and B = post-operative eGFR.

Results:

Overall there was a mean decrease of −8% after PN, 0% after laparoscopic cryotherapy and −1% after RFA. These differences were not statistically significant.

After PN 3% improved CKD stage, 59% remained the same stage, 34% deteriorated by one stage, and 4% by two stages.

Two PN patients, both with imperative indications and with pre-operative eGFR less than 15 ml/min, required permanent renal replacement therapy at 1 year post-operatively; no other cases resulted in this outcome.

Conclusions:

Overall nephron-sparing surgery results in a small mean eGFR reduction on long-term follow-up. After PN most patients retain their pre-operative CKD stage, a third drop by one stage and one in twenty-five by two stages.