SEARCH

SEARCH BY CITATION

This important publication by Ta et al. [1] demonstrates regional practice patterns in surgical intervention for renal cell carcinoma(RCC) in Australia parallels that reported in other western nations [2]. Partial nephrectomy(PN) for T1 cancers is performed less frequently outside of large urban teaching hospital centres. Resources and skills to perform PN is clearly a factor. Laparoscopic PN is a technically challenging procedure requiring high volumes and robotic PN whilst less demanding requires substantial equipment investment – both obviously problematic for smaller provincial institutions.

Ta et al. have drawn similar conclusions to previous authors in suggesting that PN is underutilised and efforts to increase use need to be considered. The missing piece in this conclusion is that as yet the precise ‘rate’ that PN should be performed has not been defined.

It is often stated that PN should be performed whenever technically feasible. The question is really whether this assertion is in fact correct. The argument for PN, if possible, is compelling on intuitive grounds. The cited evidence, whilst persuasive, is however tenuous. Randomised controlled trails constitute the best available evidence which we cannot ignore. Only one multicentre trial has been published comparing RN and PN for tumours <5cm in patients with a normal contralateral kidney– which showed no advantage for PN in terms of overall survival [3]. This finding in a large study with 10 year follow-up unfortunately is often ignored or criticised for methodological flaws to negate the findings that do not support conviction or intuitive belief.

Population studies, in addition to variations in practice, have suggested that RN is associated with an increased risk of adverse outcomes compared to PN. A potential survival advantage over a long time interval has been reported [4]. In a recent publication from the SEER data base [5] examining survival T1 tumours in patients >66 years a survival benefit was noted with PN at 1 and 3 years. This survival advantage was not sustained with no significant differences at 5 and 10 years. The earlier higher mortality in the RN group thus suggests an inherent difference between groups despite statistical corrections. If the benefit of preservation of renal mass for elective PN was substantial, within truly comparable populations, one would anticipate a sustained benefit at these longer time points.

The popular argument for elective PN, whenever feasible, reflected in conclusions by Ta et al., is parenchymal preservation to avoid chronic kidney disease(CKD). Several potential issues confound the urological literature in relation to this related to use of eGFR as an outcome end-point . Firstly eGFR is at best an estimation of renal function based on serum creatinine and far less reliable than more accurate assessments using radioisotope clearance or formulae including additional data(eg weight). It was devised as a screening tool for use in the general population to identify patients at risk of progressive chronic renal disease(CKD) due to glomerulosclerosis and not intended as an accurate assessment of renal function in any individual.

Even accepting eGFR as the only practical measure in epidemiological studies urological publications may also be misapplying its use following renal surgery in terms of categorisation of CKD and the implications following nephrectomy. Points clearly articulated in the key publication – K/DOQI Clinical Practice Guidelines for Chronic Kidney Disease: Evaluation, Classification, and Stratification [6] – have been overlooked. In this it is stated (pp 57-58) that ‘It is possible that eGFR 30-59mL/min/1.73m2 could also be normal after unilateral nephrectomy or in an older individual [6]. With the latter eGFR normally declines by 1mL/min/1.73m2 per year after 30 years of age [6] – a further point of relevance given the age of patients undergoing surgery for RCC, with the majority as in the series by Ta et al. being over 60 years of age.

Thus the significance of eGFR reductions (and CKD categorisation) as a result of parenchymal disease which in many cases (eg diabetes) is ongoing cannot be extrapolated to surgical reduction in renal mass. An eGFR of <60mL/min/1.73m2 may therefore not be an appropriate marker by which to compare PN and RN.

RCC management is rapidly evolving and currently clear regional differences in practice are evident. Surgical innovation has increased the applicability of elective PN. It is extremely important however to accept that at the present time the highest level of evidence supports the on-going applicability of RN for T1 tumours. Further randomised trials, to confirm or refute this, unfortunately are unlikely to eventuate. Hence studies demonstrating regional differences should not be seen as mandates for practice change but rather as opportunities to initiate prospective studies with both comparable cohorts and appropriate end-points applicable to surgical reductions in renal mass.

Conflict of Interest

  1. Top of page
  2. Conflict of Interest
  3. References

None declared.

References

  1. Top of page
  2. Conflict of Interest
  3. References
  • 1
    Bolton D, Ta A, Dimech M et al. Contemporary Management of Renal Cell Carcinoma in Victoria: Implications for Longer Term Outcomes and Costs. BJUI USANZ Suppl 2013; 3643
  • 2
    Dulabon LM et al. Trends in renal tumor surgery delivery within the United States. Cancer 2010; 116: 23162321
  • 3
    Van Poppel H et al. A prospective, randomised EORTC intergroup phase 3 study comparing the oncologic outcome of elective nephron-sparing surgery and radical nephrectomy for low-stage renal cell carcinoma. Eur Urol 2011; 59: 543552
  • 4
    Tan HJ et al. Long-term survival following partial vs radical nephrectomy among older patients with early-stage kidney cancer. JAMA 2012; 307: 16291635
  • 5
    Smaldone MC et al. Does partial nephrectomy result in a durable overall survival benefit in the Medicare population? J Urol 2012; 188: 20892094
  • 6
    K/DOQI clinical practice guidelines for chronic kidney disease: evaluation, classification, and stratification. Am J Kidney Dis 2002; 39 (2 Suppl 1): S1266