Partial Nephrectomy for Larger Renal Masses
Partial nephrectomy has been the procedure of choice for patients with poor renal function, tumors in solitary kidneys or bilateral renal tumors.
The efficacy of partial nephrectomy in regard to cancer control and preservation of renal function has been well documented. The traditional size limitation for masses amenable to this approach has been 4 cm in diameter.
Indications for partial nephrectomy have been expanding over the last few years. Partial nephrectomy has become an elective procedure for patients with tumors less than 4 cm in diameter and a normal contralateral kidney.
This has allowed the preservation of renal function and avoids over-treatment of benign conditions that can arise more frequently in small renal masses. Preservation of renal function has led to improved quality of life with cancer control rates similar to those of radical nephrectomy.
The loss of a kidney cannot be viewed as an innocuous procedure. Patients who undergo radical nephrectomy can develop chronic renal disease. This seems to contradict the conventional wisdom that patients do well with only one kidney, but this belief has been based upon the outcome of healthy patients who have undergone donor nephrectomies.
These individuals are not comparable with patients who have renal surgery for renal masses. Renal donors undergo stringent screening to rule out diseases that may affect long-term renal function. Patients with renal masses are often older and more likely to have comorbidities such as hypertension or diabetes. Preservation of renal tissue in this population would carry an obvious benefit, thus leading to the consideration of partial nephrectomy in patients with tumors larger than 4 cm.
Partial nephrectomy for masses 4-7 cm in diameter (T1b) can achieve tumor control similar to radical nephrectomy. Rates of distal or local recurrences have been similar to those of radical nephrectomy in patients undergoing partial nephrectomy for T1b tumors. Cancer-specific survival and metastasis-free survival also was shown to be similar between the two groups.
We recently reviewed our experience at Cleveland Clinic Florida of patients who underwent partial nephrectomy for renal masses larger than 4 cm. In this group of 14 patients, the average age was 59.9 years (range 41-80 years).
Thirteen patients had renal cell carcinoma and one had an oncocytoma, suggesting that even in the T1b stage some patients may be over-treated with radical nephrectomy if their pathology is benign. Mean tumor size was 4.98 cm (range 4.0-8.5 cm). Two of the 14 patients had solitary kidneys. Nine had a glomerular filtration rate that returned to baseline (greater than 60 mL per min/1.73 m2) after partial nephrectomy, suggesting that removing larger tumors will not compromise function in the remaining portion of the kidney.
No major complications were noted except for acute tubular necrosis in two patients. One of these patients had a solitary kidney and required post-op temporary dialysis. Creatinine levels were similar before and after surgery, with mean pre-op creatinine leves of 1.2 mg/dL (range 0.8-1.8 mg/dL) and mean post-op creatinine levels (after discharge) of 1.41 mg/dL (range 0.74-2.9 mg/dL).
The mean ischemic time was 43 minutes (range 12-75 minutes) and mean estimated blood loss was 230 cc (range 100-700cc). Margins were negative on all specimens. Follow-up to date has demonstrated no evidence of recurrences on imaging studies. One patient died of a second malignancy that developed after renal surgery. These results suggest that not only is partial nephrectomy for T1b tumors feasible, it can be performed with minimal complications and good preservation of renal function.