Pathological and Clinical Outcomes in a Large Surveillance and Intervention Cohort of Radiographically Cystic Renal Masses.

PURPOSE: We evaluated oncologic risks in a large cohort of patients with radiographic cystic renal masses who underwent active surveillance or intervention. MATERIALS AND METHODS: A single-institutional database of 4,340 kidney lesions managed with either active surveillance or intervention between 2000-2020 was queried for radiographically cystic renal masses. Association of radiographic tumor characteristics and high-grade pathology was evaluated. RESULTS: We identified 387 radiographically confirmed cystic lesions in 367 patients. Of these, 247 were resected (n=240) or ablated (n=7; n=247, 203 immediate vs 44 delayed intervention). Pathologically, 23% (n=56) demonstrated high-grade pathology. Cystic features were explicitly described by pathology in only 18% (n=33) of all lesions and in 7% (n=4) of high-grade lesions. Of the intervention cohort, African American race, male gender, and Bosniak score were associated with high-grade pathology (P < .05). On active surveillance (n=184), Bosniak IV lesions demonstrated faster growth rates than IIF and III lesions (2.7 vs 0.6 and 0.5 mm/y, P ≤ .001); however, growth rates were not associated with high-grade pathology (P = .5). No difference in cancer-specific survival was identified when comparing intervention vs active surveillance at 5 years (99% vs 100%, P = .2). No difference in recurrence was observed between immediate intervention vs delayed intervention (P > .9). CONCLUSIONS: A disconnect between "cystic" designation on imaging and pathology exists for renal lesions. Over 80% of radiographic Bosniak cystic lesions are not described as "cystic" on pathology reports. More than 1 in 5 resected cystic renal lesions demonstrated high-grade disease. Despite this finding, judiciously managed active surveillance ± delayed intervention is a safe and effective management option for most radiographic cystic renal masses.

Functional Parenchymal Volume-based Spectrum Score Is Able to Quantify Ischemic Injury After Partial Nephrectomy.

OBJECTIVE: To externally validate the Spectrum Score (SS) using a modified calculation based on functional parenchymal volumes (FPVs) instead of renal scans. The SS quantifies acute ischemic injury in the ipsilateral kidney after partial nephrectomy. However, this metric requires renal split function assessment via renal scans, which may be unavailable in routine practice. METHODS: We retrospectively reviewed patients with a solitary renal mass and contralateral kidney who underwent partial nephrectomy at our institution between 2015 and 2017. FPVs were calculated using cylindrical volume approximation and used to quantitate relative renal function. Based on renal split function and parenchyma preserved, we determined creatinineideal, assuming no ipsilateral kidney ischemic injury, and creatinineworst-case, assuming temporary ipsilateral kidney nonfunction. FPV-based SS was defined as follows: (observed peak creatinine-creatinineideal)/(creatinineworst-case-creatinineideal). Functional recovery was defined as follows: (% function saved)/(% parenchyma preserved). Factors associated with FPV-based SS and functional recovery were assessed using linear regression. RESULTS: We assessed 174 patients with a median renal mass size of 2.7 cm (IQR 2.0-3.6), warm ischemia time of 26.0 minutes (IQR 19.0-34.3), and parenchyma preservation of 92.6% (IQR 80.8-100). Preoperative ipsilateral kidney % split function (P = .003), preoperative ipsilateral kidney glomerular filtration rate (P = .045), and warm ischemia time (P = .005) were independently associated with FPV-based SS. Only FPV-based SS (P<.001) was independently associated with functional recovery. CONCLUSION: The FPV-based SS, which does not require renal scans, quantifies acute ipsilateral renal dysfunction and predicts functional recovery after partial nephrectomy.