Outcomes for Atypical Tumor Recurrences Following Minimally Invasive Kidney Cancer Operations

BACKGROUND: We managed a cohort of patients treated with minimally invasive surgery (MIS) for a kidney tumor presenting with atypical tumor recurrence (ATR) involving port sites, intraperitoneal carcinomatosis, and nephrectomy bed/perinephric tumor implants. OBJECTIVE: To determine the clinical characteristics, management, and oncologic outcomes for patients with localized renal cell carcinoma (RCC) who develop ATR following curative-intent MIS for partial or radical nephrectomy. DESIGN, SETTING, AND PARTICIPANTS: The study cohort comprised patients from 1999 to 2021 with localized RCC managed at Memorial Sloan Kettering Cancer Center (New York, NY, USA) after MIS for partial or radical nephrectomy who developed ATR. Outcome measurements and statistical analysis: We collected data on clinicopathologic characteristics, treatments, time to ATR, and overall survival. RESULTS AND LIMITATIONS: The median age of the 58 RCC patients was 61 yr. Forty-one patients (71%) were male, 26 (45%) had robot-assisted operations, and 39 (67%) had clear cell RCC. Twenty-nine patients had stage pT1 disease (50%) and ten (17%) had positive surgical margins. The most common ATR site was perinephric/nephrectomy bed implants (n = 28, 48%). Management included: surgical resection alone (n = 11, 19%), systemic therapy alone (n = 12, 21%), surgical resection and systemic therapy (n = 17, 29%), and palliative care (n = 8, 14%). At median follow-up of 59 mo (interquartile range [IQR] 28–92), the median time to ATR was 12 mo (IQR 5–28). Overall survival at 5 yr was 69.0% (95% confidence interval 57.4–83.1%) with only nine patients alive with no evidence of disease. Limitations include the potential for referral, detection, and selection biases, as well as uncertainty regarding the true incidence of ATR. CONCLUSIONS: ATR following MIS for partial or radical nephrectomy is an understudied, poor prognostic event which leads to a heavy treatment burden. Further investigation into its etiology and means of prevention is warranted. PATIENT SUMMARY: Patients experiencing recurrence of kidney cancer in an atypical site require a heavy treatment burden and have a guarded overall prognosis. Continued research is needed to determine the precise incidence of these recurrences and identify methods for mitigating them.