Presentation Authors: Harmenjit Brar*, London, Canada, Rodney Breau, Ottawa, Canada, Anil Kapoor, Hamilton, Canada, Neal Rowe, Ottawa, Canada, Garson Chan, Danielle Nash, Stephanie Dixon, Eric McArthur, London, Canada, Camilla Tajzler, Hamilton, Canada, Ravi Kumar, Ottawa, Canada, Christopher Vinden, Jonathan Izawa, Amit Garg, Patrick Luke, London, Canada
Introduction: Partial nephrectomy has become the gold standard for localized renal masses as it provides excellent oncologic control while preserving renal mass and global renal function. However, it remains controversial if partial nephrectomy improves mortality, renal-related events and cardiovascular disease. The objective of this study is to assess the impact of comorbidity on long-term outcomes.
Methods: Comorbidity was estimated using the Johns Hopkins Adjusted Clinical Group (ACG) system which provided Aggregated Diagnostic Groups (ADG) scores. This score was determined based on resource use, procedures, and diagnoses in the year prior to nephrectomy, with a higher score indicative of greater expected resource utilization. The primary outcome was all-cause mortality, with two pre-specified comorbid groups: ADG < 7.5 or >7.5. Secondary outcomes included major cardiovascular events and non-cancer mortality.
Results: Between 2002-2010, we identified 575 partial and 882 radical nephrectomies for tumors measuring 7cm or less at 3 academic centers. The mean (standard deviation) 1-year post-operative eGFR was 71 (22) mL/min/1.73 m2 and 52 (13) mL/min/1.73 m2 in the partial nephrectomy and radical nephrectomy group, respectively. Mortality rates were highest in the ADG >7.5 group with 2.9 vs 1.5 per 100 person years in the partial nephrectomy group and 4.9 vs 3.4 per 100 person years in the radical nephrectomy group. However, there was no evidence that ADG comorbidity stratification modified long term outcomes between the partial and radical nephrectomy groups. All-cause mortality HRs are as follows: ADG < 7.5 HR 1.62, 95% CI (1.04-2.52) versus ADG >7.5 HR 1.29, 95% CI (0.87-1.89) with an interaction p-value that was not significant (p=0.46). This trend continued for non-cancer mortality and cardiovascular death.
Conclusions: The absolute death rate was nearly doubled in the higher comorbid group (ADG >7.5) indicating ADG scoring properly risk stratify these patients. However, comorbidity risk stratification did not modify long-term outcomes between the partial nephrectomy versus radical nephrectomy group in all-cause mortality, non-cancer mortality and cardiovascular death.