Partial nephrectomy is the gold standard surgical treatment for kidney cancers <4cm (T1a) and select 4-7cm (T1b) cancers – with equivalent cancer control and better preservation of kidney function than radical nephrectomy
This critical review of 69 published articles gives excellent insight into the benefits of partial nephrectomy over radical nephrectomy for T1a (<4cm) and select T1b (4-7cm) kidney cancers. Partial nephrectomy is now considered the gold standard surgical treatment for these kidney cancers. The cancer control for these stages are equivalent. Importantly 20-30% of these tumors are benign or have low malignant potential – another argument in favor of partial nephrectomy. The use of partial nephrectomy has risen from 10% of all nephrectomy surgery between 1988-2000 to 50-60% between 2004-2007, in the US and Europe. It is generally known that most radical nephrectomies are performed laparoscopically, while most partial nephrectomies are performed open. The laparoscopic partial nephrectomy is not common because the technical degree of difficulty may compromise outcomes in low volume hands. Whereas now with robotic assisted surgery, minimally invasive partial nephrectomy is becoming much more technically feasible. In terms of renal function outcomes:
- Several single institution series have demonstrated lower postoperative serum creatinine and/or lower proteinuria after partial v radical nephrectomy
- This suggests a lower risk of chronic kidney disease after partial nephrectomy
- Chronic kidney disease has been implicated as a risk factor for coronary disease, stroke, peripheral vascular disease and heart failure, and hospitalization and death.
In one study of 662 patients with small (<4cm) kidney cancers the 5 year probability of being free from chronic kidney disease was 67% v 23% in favor of partial nephrectomy over radical nephrectomy. Unfortunately the evidence in this area is not level 1 randomized so we must rely of large number level 3-4 series. In one large population study of 7769 men comparing partial and radical nephrectomy those who underwent partial nephrectomy had an absolute overall survival benefit of 4.9% at 5 years and 3.1% at 10 years after surgery. Also those who had radical nephrectomy had a 1.23 fold increased risk of overall mortality. In terms of oncologic outcome for T1a tumors:
- The 5-10 year cancer specific survival rate is 92-100%
- The local recurrence rates are <5%
- The positive surgical margin rates are <5%
- Two laparoscopic series had local recurrence rates of <3%
- Oncologic principles suggest a 1cm rim of normal tissue around the tumor should be excised rather than just enucleating the tumor.
Very careful selection must guide any surgeon who attempts partial nephrectomy for sizes >4-7 cm.