Ki-67 index and percentage of sarcomatoid differentiation were two independent prognostic predictors in sarcomatoid renal cell carcinoma

Abstract

PurposeTo identify whether and which of pathological features of sarcomatoid differentiation (SD) in renal cell carcinoma (RCC) can be used as independent predictors associated with overall survival (OS).Materials and methodsAfter institutional review board approval, patients with a diagnosis of sarcomatoid RCC (sRCC), spindled RCC, or RCC with the presence of spindle cells between 2003 and 2017 were further selected and re-examined. The primary pathological features including histological subtypes, tumor necrosis, Ki-67 index of SD, and the percent of SD (%SD) were included into analysis. Histological subtypes were categorized into clear-cell RCC and nonclear-cell RCC. Ki-67 index of SD was confirmed by immunohistochemical staining. %SD was estimated through reviewing all of the tumor sections microscopically and then giving an approximate %SD within the entire tumor. The clinical relevant prognostic predictor’s association with OS was analyzed within Cox proportional hazards regression models. Survival curves were generated using the Kaplan–Meier method, and OS differences were compared using the log-rank test.ResultsA total of 2,089 consecutive patients of RCC were referred to our department, of whom 62 (3.0%) patients were identified with histological element of SD after re-examining the available slides of suspicious cases. Finally, 53 patients were included into survival analysis after excluding 9 patients without adequate information. Thirty-eight (71.7%) patients died at last follow-up. The median OS for all patients was 11.0 months from the date of surgery. In patients with clinical distant metastasis (cM1), the median OS was only 3 compared with 21 months for patients with no clinical distant metastasis (cM0). Tumor stage, status of clinical distant metastasis, Ki-67 index, and %SD were independent predictors of multivariate analysis in overall 53 patients. However, in the cohort of cM0 patients, we found that only %SD and Ki-67 index were two independent predictors of OS in multivariate analysis.ConclusionPatients with sRCC are associated with very poor prognosis. Ki-67 index of SD and %SD were identified as the two most important independent predictors particularly for nonmetastatic patients. The limitations of our study were also observed, and further studies are needed.

Clinicopathologic features and prognostic factors in patients with renal cell carcinoma with sarcomatoid differentiation

“…Yu et al (26) described 42 patients with RCCs and confirmed that patients with positive immunophenotypes for p53, Bcl‐2, and CAIX had an adverse outcome. Wang et al (27) found that the Ki‐67 index of sarcomatoid differentiation was one of the most important independent predictors, particularly for nonmetastatic RCCs patients. Kawakami et al (10) compared the highly immunosuppressive characteristics between RCCs and an appropriate ccRCC control.…”

Clinicopathologic factors linked to oncologic outcomes for renal cell carcinoma with sarcomatoid dedifferentiation: A PRISMA-compliant systematic review and meta-analysis

“…By far, a number of studies have examined various clinical and pathological variables as prognostic factors in patients with sRCC. Several significant prognostic factors have been found, including T stage, lymph node status, distant metastasis, histology type, percentage of sarcomatoid dedifferentiation, and blood markers (2)(3)(4)(7)(8)(9)(10)(11)(12)(13)(14)(15). Moreover, several prognostic models have been developed to accurately predict tumor prognosis in each patient with sRCC (4, 11,14).…”