Capsular involvement in patients undergoing partial nephrectomy for localized renal cell carcinoma: an adverse pathological finding?

Renal capsular invasion is a prognostic biomarker in localized clear cell renal cell carcinoma

Renal capsular invasion (RCI) and lymphovascular invasion (LVI) are potential prognostic factors of significance in renal cell carcinoma (RCC). We evaluated the independent prognostic implications of RCI and LVI in localized clear cell RCC based on a large multi-institutional cohort. 6, 849 patients who had undergone radical or partial nephrectomy for RCC were included. Associations between recurrence and RCI or LVI were analyzed by constructing statistical models that combined Cox proportional hazard regression and propensity score matching. To analyze RCI, 2, 733 patients including 603 patients with RCI were enrolled. To analyze LVI, 3, 586 patients including 121 patients with LVI were enrolled. Recurrence was observed in 75 (12.4%) patients with RCI and 134 (6.3%) patients without RCI. In all statistical models, RCI was significantly associated with an increased risk of recurrence. Recurrence was observed 29 (24.0%) patients with LVI and 207 (6.0%) patients without LVI. LVI was significantly associated with an increased risk of recurrence only in non-adjusted univariate models, but not in multivariate adjusted analysis or propensity score matching models. In conclusion, these findings suggest that RCI could be a significant risk factor for localized clear cell RCC recurrence. In contrast to RCI, LVI cannot be an independent prognostic variable.

Classification of Histologic Patterns of Pseudocapsular Invasion in Organ-Confined Renal Cell Carcinoma

A standardized histologic definition and classification of the patterns of renal tumor pseudocapsular invasion (RTPI) in renal cell carcinoma (RCC) is not available. We classified RTPI into 2 main histologic patterns: expansive and infiltrative RTPI. Patients with organ-confined RCC and infiltrative RTPI had a greater risk of cancer-specific death and might require stricter postoperative surveillance strategies.

INTRODUCTION

A standardized histologic definition and classification of patterns of renal tumor pseudocapsular invasion (RTPI) in renal cell carcinoma (RCC) is not available. The aim of the present study was to propose a classification of RTPI patterns and assess their correlation with other pathologic features and prognosis.

PATIENTS AND METHODS

The renal tumor pseudocapsule was assessed by 2 expert genitourinary pathologists on the histologic slides of 190 specimens from radical nephrectomy performed for organ-confined (pT1-pT2) RCC. The histologic patterns of RTPI were classified and described. The association between the RTPI patterns and other pathologic features was assessed. The Kaplan-Meier method was used to calculate the survival functions, and Cox regression models were used to assess the predictors of cancer-specific survival.

RESULTS

RTPI was classified into 2 main histologic patterns (expansive and infiltrative). Expansive and infiltrative RTPI was observed in 39.5% and 51.6% of cases, respectively. A significant association between the RTPI pattern and Fuhrman grade (P = .006) and RCC histologic subtype (P = .034) was detected. Patients with infiltrative pseudocapsular invasion had significantly poorer 5- and 10-year cancer-specific survival rates than patients with expansive invasion or no invasion (93.6% vs. 98.9% and 84.9% vs. 93%, respectively; P = .039). The presence of infiltrative pseudocapsular invasion was a significant predictor of cancer-specific survival (hazard ratio 4.38, 95% confidence interval 1.04-20.27).

CONCLUSION

An expansive and an infiltrative RTPI pattern can be described. In our study, patients with organ-confined RCC and an infiltrative RTPI pattern had a greater risk of cancer-specific death and might require stricter postoperative surveillance strategies.

Capsular invasion in renal cell carcinoma: a meta-analysis

OBJECTIVES

Capsular invasion is frequently detected in localized renal cell carcinoma (RCCs) samples. Whether patients with localized RCCs and capsular invasion will suffer poorer clinical outcome than those without this pathologic finding is still at issue.

MATERIALS AND METHODS

We performed a systematic literature research of Central, Medline, Embase, and Chinese database CNKI and VIP. Cohort studies comparing the prognosis in patients with localized RCCs and with or without capsular invasion were included. Incidence of capsular invasion in different Fuhrman grade, primary TNM stage, and clinical outcome were analyzed.

RESULTS

Six cohort studies with 2,295 eligible patients were identified. Capsular invasion was presented in 500 specimens (21.79%). Lower grade (Fuhrman I/II vs. Fuhrman III/IV) and stage (pT1 vs. pT2) diseases were associated with lower incidence of capsular invasion, with OR = 0.56, 95% CI[0.37-0.85] and OR = 0.35, 95% CI[0.25-0.49], respectively. Our pooled analysis showed patients with capsular invasive had 1.80 times the risk of tumor recurrence than patients without these findings (HR = 1.8, 95% CI [1.21, 2.68]), and patients with localized RCCs and capsular invasion were detected at 4.93 times risk in developing cancer related death than those without its presence during follow up (HR = 4.93, 95% CI [2.14, 11.35]).

CONCLUSION

Patients with localized RCCs and capsular invasion are of poorer prognosis than those without this finding. Capsular invasion may serve as an additional factor in stratifying patient with localized RCCs.