The talk is anchored around a case presentation of a 57 year old woman who presents with an incidental finding of two 3 cm renal masses of the left kidney, otherwise asymptomatic. Her medical history is significant for diabetes (on metformin), OA (takes NSAIDs) and no family history of RCC. On labwork, her serum creatinine is normal – but her eGFR is 70 mL/min. Fortunately, she does not have proteinuria, as this may be a marker of worse medical-renal disease.
She has biopsy proven clear cell RCC, and she has a few management options: surveillance, partial nephrectomy, radical nephrectomy or thermal ablation. But, naturally, the patient has a few concerns: what will provide optimal cancer control, but also which will best preserve her kidney function?
First, there are numerous nomograms out there to estimate risk of renal failure in the general population – including the KidneyFailureRisk.com, which puts her risk of kidney failure in 5 years at 0.05% (or very low risk). This is independent of her medical comorbidities or RCC management.
A very important slide that he shared, based on multiple prior studies, estimates the decrease in renal function following urologic interventions for RCC:
- Surveillance – None
- Partial Nephrectomy - ~9%
- Focal therapy / ablation – ~8%
- Radical nephrectomy - ~30%
However, medical-renal disease is a completely different entity. Studies have repeatedly demonstrated that hypertension, diabetes, and cardiovascular disease are associated with ~5% decrease in renal function per year.1,2
So, in that same patient, a combination of medical and surgical insult over 5 years may have a significant impact:
In this slide, he specifically point out that the short-sighted view is that partial nephrectomy would be better for this patient due to nephron-sparing – when all we consider is surgical insult. The better view of this is that the area for maximal renal preservation is actually controlling her medical renal disease and preventing further insult!
This patient went on to receive partial nephrectomy with good final pathology. More importantly, she worked closely with her nephrologist and PCP to control her diabetes, control her blood sugar, lose weight (came off DM medications) and stop NSAID use (switched to Tylenol). As a result, at her 3-year post-op visit, her eGFR was 66 – little to no impact. While, as urologists, we could congratulate ourselves on a job well done – the bulk of that work was on the part of the nephrologist and primary care doctor.
Now, in high risk patients, those with GFR < 30 or even < 15, medical optimization becomes even more important. Naturally, there is more of an absolute indication for nephron-sparing, but it is critical to involve your internal medicine colleagues in the management of these patients.
In summary:
- ESRD due to surgical nephron removal is very rare
- Most ESRD is due to medical-renal disease
- To preserve renal function:
- Minimize nephron loss
- Avoid nephrotoxins
- Optimize medical management of DM, hypertension and CVD
References:
- Leavy Lancet 2012
- Lane J Urol 2013