Master summarized the arguments for metastasectomy, with advocates believing that metastasectomy can help palliate tumor-related symptoms, that metastasectomy can delay time to the utilization of systemic therapy (or avoidance of systemic therapy altogether), and that in a fraction of patients, a cure is possible. Those who question the efficacy of metastasectomy often argue that the retrospective data that associates metastasectomy and longer survival is explained by unmeasured enrichment, such as more favorable disease biology and good patient selection by the surgeon.
There have been several retrospective studies that have evaluated the overall safety of metastasectomy. One such study by Myer et. Al. evaluated 1102 patients who underwent metastasectomy for oligometastatic RCC and found that the overall complication rate for this procedure was 45%, with 28% being Clavien III/IV. Patients undergoing liver resection for metastatic RCC had the highest overall complication rate, with an OR of 2.59.
Dr. Master then reviewed the retrospective data of patients undergoing metastasectomy in the era of targeted therapy for RCC. One NCDB study from Sun and colleagues reviewed 7000 patients with oligometastatic RCC, 28% of whom underwent a metastasectomy. Those who underwent a metastasectomy had an improved overall survival (HR 0.77, p = 0.008). He acknowledged that the role of metastasectomy in the era of immuno-oncology has yet to be recognized, as there a no mature data at this point.
He reviewed the predictors of improved overall survival in patients undergoing metastasectomy and cited a systematic review from Achkar and colleagues that showed that the strongest predictor of a survival benefit is a complete resection of the metastatic lesion. He also noted that while rare, RCC metastatic lesions to the pancreas and thyroid gland tend to be favorable sites of metastasis, with high 5-year overall survival rates.
He then discussed the interim results of the RESORT trial, which is an ongoing phase II randomized clinical trial that is evaluating the efficacy of metastasectomy with sorafenib versus metastasectomy with subsequent observation. The primary endpoint of the trial is recurrence-free survival (RFS). On interim analysis, it was found that there was a median RFS was 29 months in the sorafenib + metastasectomy arm, versus 35 months in the metastasectomy + observation arm. There were 22% of grade III adverse events in the sorafenib arm versus only 3% in the observation arm. The authors concluded at interim analysis that sorafenib is safe to use in this scenario but did not affect RFS in this patient population.
Dr. Master concluded the lecture by describing the patient he felt would be the ideal candidate to undergo metastasectomy. He felt that the ability to perform a complete resection of the metastatic lesion is one of the prognostic factors best supported in the current literature. Furthermore, patients with solitary or low-burden metastatic lesions are better served by surgical intervention. Finally, patients with an absence of nodal metastases and an absence of liver metastatic lesions tend to have a better prognosis post-metastasectomy. He feels that a large phase III randomized controlled clinical trial is necessary to better clarify the role of metastasectomy in patients with oligometastatic RCC.
Presented by: Viraj Master, MD, Ph.D., Emory University, Atlanta, Georgia
Written by: Brian Kadow, MD. Society of Urologic Oncology Fellow, Fox Chase Cancer Center, Philadelphia, Pennsylvania at the 19th Annual Meeting of the Society of Urologic Oncology (SUO), November 28-30, 2018 – Phoenix, Arizona