PAST
Surgery is the primary treatment modality for retroperitoneal sarcomas (RPS), and the only curative therapy. Complete surgical resection is critical to achieve good oncologic outcomes, but the location and insidious presentation of RPS result in high rates of contiguous organ invasion at presentation; resection of one or more organs in addition to the tumor occurs in ~40% of patients.1 The kidney is the one of the most frequently resected organs at time of RPS resection, second only to bowel.
Despite the oncologic benefit of R0/R1 resections, the risks of nephrectomy must be carefully considered in this patient population; the catastrophic outcome of renal injury progressing to ESRD and permanent dialysis must be avoided whenever possible. The average 5-year survival for a patient started on dialysis is only 42.9%, lower than many reported survival rates for RPS.2,3 Additionally, dialysis severely impacts quality of life for patients already burdened by cancer-related treatment and stressors.
PRESENT
Our study utilized the United States Sarcoma Collaborative database to perform the largest and only matched retrospective analysis of the impact of nephrectomy on postoperative renal function to date.4 The matched cohort consisted of 411 patients, and patients that underwent nephrectomy had higher rates of short term renal dysfunction postoperatively, including acute kidney injury (AKI) (15% vs 4%, p<0.01) and acute renal failure (ARF) (5% vs 1%, p=0.04). After controlling for confounding variables, nephrectomy was associated with 5 times greater odds of postoperative AKI and ARF.
However, no patients in the matched cohort required dialysis postoperatively. Additionally, when we looked at the unmatched cohort of 858 patients, only 3 (0.3%) required postoperative dialysis. Only one out of these 3 patients underwent nephrectomy with their RPS resection, and the two patients with complete data available had severe CKD prior to surgery (eGFRs ≤44). Thus, in all patients undergoing RPS resection, the risk of postoperative dialysis is very low (<0.5%) and likely related to poor preoperative renal function.
In patients with adequate renal function undergoing RPS resection, nephrectomy should not be withheld due to concerns about postoperative renal function.
FUTURE
The rarity of retroperitoneal sarcoma and the difficulty of preoperative prediction of the need for nephrectomy makes a future randomized controlled trial of nephrectomy in RPS resection unlikely. However, continued accrual of patients in multi-institutional sarcoma collaboratives will allow for more granular analyses of risk factors for postoperative renal dysfunction following RPS resection, among many other important clinical questions.
As the treatment for RPS evolves and increasingly includes nephrotoxic chemotherapy such as ifosfamide, future work will be needed to determine the impact of combined nephrectomy and nephrotoxic therapies on long-term renal dysfunction.
Footnotes
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Disclosures: The authors declare no conflicts of interest.
References
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