Ajay K. Singh, MBBS, FRCP, MBA
Brigham and Women’s Hospital and Harvard Medical School
In 2017, there were approximately 64,000 new cases of kidney cancer in the United States1, representing nearly 4% of all cancer cases. Patients with kidney cancer are usually evaluated for surgical management unless the cancer is advanced. The traditional surgical approach has been a radical nephrectomy (RN). However, with better imaging (computed tomography or magnetic resonance imaging) smaller tumors are being detected. A decision around whether the patient should undergo nephron sparing surgery (NSS) is frequently discussed with the patient and an opinion is sought from a nephrologist. NSS usually implies partial nephrectomy (PN).
Physicians are confronted with a dilemma. Because of advances in minimally invasive techniques and robotic technology (the daVinci robot)2, PN now has greater technical feasibility and is associated with better outcomes such as less bleeding and lower ischemia time. In addition, there is a lower likelihood of converting to a RN. However, robotic technology is usually available only in major centers and is expensive.
Nephrologists are asked to help estimate the post-operative short- and long-term risk of developing kidney failure requiring dialysis (end-stage renal disease). A related question is whether the risk of developing kidney failure is lower if the patient undergoes a PN rather than a RN. An even more elusive question is whether PN with robotic surgery is superior to a traditional laparoscopic approach.
Data on first of these two issues is quite limited. One recent study3 published in 2014 represented a secondary analysis of the European Organization for Research and Treatment of Cancer (EORTC) randomized trial 30904. PN was compared to RN in 541patients with a small (≤5 cm) renal mass and normal contralateral kidney. PN was associated with a decreased incidence of moderate renal dysfunction, but was not associated with a reduced incidence of kidney failure or the need for dialysis. Nor did PN result in improved survival.
In the January 2018 issue of the Journal of the American Society of Nephrology, John Leppert and colleagues from Stanford4, compared the effect of PN versus RN on the incidence of clinically significant (stage 4 and higher) chronic kidney disease (CKD). The study population was veterans treated for kidney cancer in the Veterans Health Administration between 2001and 2013.
In the total cohort of 14,129, Leppert and colleagues report that 7.9% of patients developed incident stage 4 or higher CKD (n=1121). Furthermore, 14.2% of patients with normal or near-normal kidney function had a drop in estimated glomerular filtration rate (eGFR) to lower than 30 to 44 mL/min/1.73m2 (stage 3b CKD) or worse. Risk factors for the decline in kidney function included impaired kidney function at baseline (i.e., preoperatively), resection of larger tumors by PN (T2 versus T1 tumors, >7cm versus <7 cm, respectively), and older patient age at the time of surgery.
A key finding of the study was that patients who underwent PN had a 60% lower risk of a substantial decline in eGFR (developing stage 4 or higher CKD) compared with those who underwent RN. As well, among patients with normal or near-normal kidney function preoperatively, choosing to do a partial nephrectomy resulted in a substantial reduction in the risk (~80% reduction) of developing stage 3b or higher CKD compared with patients who underwent a RN. Furthermore, PN patients had a significantly reduced risk of mortality (30%-45% reduction) when compared with patients who underwent a radical nephrectomy.
Another interesting finding was that most of the loss in eGFR (~80%) occurred within the first year of surgery. After this initial drop in eGFR, only a minority of patients progressed, a pattern of decline unlike what would be expected if the patient had CKD from parenchymal kidney disease, raising the question of whether these patients had truly developed CKD.
So, what is the bottom-line? This is an important, well-conducted study. The key practice-influencing finding is that for the appropriate patient with kidney cancer, PN results in a substantially lower risk of CKD than RN, and is associated with better patient outcomes. At least until better data emerge, PN should be preferred over RN.
- https://seer.cancer.gov/statfacts/html/kidrp.html Accessed January 15, 2018
- George J. S. Kallingal, Sanjaya Swain, Fadi Darwiche, et al., “Robotic Partial Nephrectomy with the Da Vinci Xi,” Advances in Urology, vol. 2016, Article ID 9675095, 5 pages, 2016. doi:10.1155/2016/9675095
- Scosyrev E, Messing EM, Sylvester R, et al. Renal function after nephron-sparing surgery versus radical nephrectomy: results from EORTC randomized trial 30904. Eur Urol. 2014;65:372–7. http://dx.doi.org/10.1016/j.eururo.2013.06.044.
- Leppert JT, Lamberts RW, Thomas IC, Chung BI, Sonn GA, Skinner EC, Wagner TH, Chertow GM, Brooks JD. Incident CKD after Radical or Partial Nephrectomy. J Am Soc Nephrol. 2018 Jan;29(1):207-216.