There are several classic studies that have addressed the risks and benefits associated with PN. Dr. Campbell argued that the findings of some of these studies subsequently led to inaccurate inferences and clinical practice. For example, Go et al 2004 showed that increasing degrees of CKD are associated with cardiovascular events and reduced survival, and the inference was that PN is preferred to preserve renal function, thus improve survival. Similarly, Huang et al 2006 showed that while 26% of renal mass patients have preexisting CKD, 3 years after surgery, PN is associated with CKD 20% of the time and RN 65% of the time; the inference was that PN prevents CKD, however, it is clear that pre-existing CKD, regardless of surgical technique, plays a major role in long-term CKD. A meta-analysis comparing PN to RN by Kim and Thompson et al 2012 reviewed 36 studies, all but one retrospective, which predominantly showed advantages for PN in terms of CKD and all-cause mortality.
Despite significant concerns for selection bias related to these studies, in 2011, the treatment paradigm focused heavily on PN as the “right” treatment when possible, and some equated RN to malpractice. In 2011, Van Poppel et al published results of their prospective randomized trial comparing elective PN and RN (EORTC 30904). They found an advantage for RN related to lower morbidity and PN related to better renal function, but no improvement in overall survival for PN. The study demonstrated that better renal function did not lead to better overall survival, contrary to prior beliefs described above. The findings further suggested that selection bias is a major factor in the body of literature.
A retrospective study by Gershman et al 2018 reviewed 1,609 patients with RCC who had RN or PN for cT1 renal masses. The authors performed propensity scoring to adjust for imbalances between the groups, and they found that while RN is associated with worse renal function, it was not associated with non-renal cancer-related mortality or all-cause mortality on multivariate analyses. Dr. Campbell asserts that selection bias is driving the survival outcomes, not the functional differences related to GFR, and argues that a randomized trial comparing RN and PN for cT1b/T2 is logical and necessary. More important than renal function, the oncologic safety of PN for these tumors remains largely unknown. Unfortunately, despite multiple attempts by several investigators, trial proposals were rejected in 2013, 2016, and 2019. The current practice for elective cT1b/T2 lesions is based on individualized decision-making and recognition of paucity of high-quality data.
The following factors must be considered:
- Age, comorbidities
- Tumor focality, family history of RCC
- Global GFR and split renal function
- Tumor complexity
- Careful review of imaging features
Presented by: Steven C. Campbell MD, PhD, Professor of Surgery; Residency Program Director; Vice Chairman of Urology, Center for Urologic Oncology, Glickman Urological & Kidney Institute, The Cleveland Clinic, Cleveland, Ohio
Written by: Selma Masic, MD, Urologic Oncology Fellow (SUO), Fox Chase Cancer Center, @selmasic, at the 20th Annual Meeting of the Society of Urologic Oncology (SUO), December 4 - 6, 2019, Washington, DC