Histopathology in surgically treated renal cell carcinoma: Is there a survival difference when stratified by stage?

5089

Background: The impact of renal cell carcinoma histopathology (RCC) on survival has been conflicting and limited to retrospective institutional studies. Therefore, we sought to determine the role of RCC histopathology on stage-specific survival rates in a population-based cohort. Methods: We utilized the National Cancer Institute's Surveillance, Epidemiology, and End Results database and identified 21,258 patients who underwent partial or radical nephrectomy for RCC between 1996 and 2004. Patients were stratified based on histopathologic diagnosis (clear cell, papillary, chromophobe, sarcomatoid, and collecting duct) and pathologic stage. We performed Cox-proportional hazard modeling and Kaplan-Meier survival analyses to determine overall- and cancer-specific survival. Results: Using univariate analysis, histopathology significantly impacted overall- and cancer-specific survival (p< 0.001). Specifically, patients with papillary and chromophobe variants had lower stage disease at the time of surgery and had improved survival compared to clear cell subtypes, (HR: 0.50; 95% CI, 0.42–0.60 and HR: 0.31; 95% CI, 0.22–0.44, respectively). When controlled for stage, improved outcomes for chromophobe and papillary histologies persisted, although it did not achieve statistical significance at all stages. On the other hand, patients with sarcomatoid disease were more likely to present with high stage disease and invariably had worse survival compared to clear cell carcinoma (HR: 8.74; 95%, CI 7.70–9.91). When controlled for stage, this difference achieved statistical significance across all stages (p< 0.001). Conclusions: Histopathologic subtype in patients with RCC does predict overall- and cancer-specific survival. Patients with sarcomatoid RCC, even those presenting with low-stage disease, have poor survival. These findings may give further value to recent data suggesting the increased utility of percutaneous renal biopsy and its potential impact on management.

[Table: see text]

No significant financial relationships to disclose.

The effect of sirolimus on prostate-specific antigen (PSA) levels in male renal transplant recipients without prostate cancer

In kidney recipients, the immunosuppressant sirolimus has been associated with a decreased incidence of de novo posttransplant malignancies (including prostate cancer). But the effect of sirolimus on the prostate-specific antigen (PSA) blood level, an important prostate cancer screening tool, remains unknown. We studied male kidney recipients >50 years old (transplanted from January 1994 to December 2006) without clinical evidence for prostate cancer. Pre- and posttransplant PSA levels were analyzed for 97 recipients (n = 19 on sirolimus, n = 78 on tacrolimus [control group]). Pretransplant PSA was similar for sirolimus versus tacrolimus recipients (mean, 1.8 versus 1.7 ng/mL, p = 0.89), but posttransplant PSA was significantly lower for recipients on sirolimus (mean, 0.9 versus 1.9 ng/mL, respectively, p < 0.001). The mean difference between pretransplant and posttransplant PSA was -0.9 ng/mL (50.0%, p = 0.006) for the sirolimus group versus +0.2 ng/mL (+11.8%, p = 0.24) for the tacrolimus group. By multivariate analysis, only pretransplant PSA and immunosuppression with sirolimus independently impacted posttransplant PSA. Our data strongly suggest that sirolimus is associated with a significant PSA decrease in kidney recipients. Future studies must investigate the clinical implications of our findings for the use of PSA for prostate cancer screening in male kidney recipients on sirolimus.

Pancreatic beta-cells expressing the Arg64 variant of the beta(3)-adrenergic receptor exhibit abnormal insulin secretory activity

The Arg64 beta(3)-adrenergic receptor (beta(3)AR) variant is associated with an earlier age of onset of diabetes and lower levels of insulin secretion in humans. The aims of this study were to investigate whether beta(3)AR is expressed by islet cells, if receptor binding affects insulin secretion and, finally, if the beta(3)AR Arg64 variant induces abnormal insulin secretory activity. Human pancreas extracts were subjected to RT-PCR, Western blotting and immunostaining analyses. DNA sequencing and Western blotting demonstrated that the beta(3)AR gene is transcribed and translated in the human pancreas; immunostaining showed that it is expressed by the islets of Langerhans. Cultured rat beta-cells responded to human beta(3)AR agonists in a dose- and time-dependent manner. Transfection of cultured rat beta-cells with the wild-type human beta(3)AR produced an increased baseline and ligand-dependent insulin secretion compared with parental cells. On the other hand, cells transfected with the Arg64 variant of the beta(3)AR secreted less insulin, both spontaneously and after exposure to human beta(3)AR agonists. Furthermore, while transfection with the wild-type beta(3)AR preserved the glucose-dependent secretion of insulin, expression of the variant receptor rendered the host cells significantly less responsive to glucose. In summary, cells express the beta(3)AR, and its activation contributes to the regulation of insulin secretion. These findings may help explain the low levels of insulin secretion in response to an i.v. glucose tolerance test observed in humans carrying the Arg64 polymorphism.

Enhancing insulin action: from chemical elements to thiazolidinediones

Type 2 diabetes is characterized by two fundamental biological defects: a reduced glucose-dependent insulin secretion and an increased resistance to the action of insulin at the level of various target tissues. While the use of agents to improve the insulin secretory activity of the islets of Langerhans has witnessed the flourishing of several new drugs over the years, a much greater difficulty has been experienced in the search for insulin-sensitizing drugs. The aim of this article is to critically review this topic, and to emphasize the importance of providing alternative strategies for the management of Type 2 diabetes.