Faculty Bibliography

OBJECTIVE: To compare the surgical outcomes of elderly patients with renal masses treated with laparoscopic partial nephrectomy (LPN) or laparoscopic cryoablation (LCA). PATIENTS AND METHODS: All 15 patients who had LCA at the authors' institution between May 2003 and July 2005 were included, and compared with a matched cohort of 15 patients selected by patient age and tumour size, from a pre-existing database of 104 patients who had LPN from July 2002 to July 2005. The two groups were compared for gender, number of comorbidities, American Society of Anesthesiologists status (ASA), body mass index (BMI), baseline renal function and haematocrit, location and size of lesion, length of stay, operative time, estimated blood loss (EBL), transfusion rate, number and type of complications, conversion rate, and postoperative renal function and haematocrit. RESULTS: The two groups were similar in age, sex, BMI, ASA, baseline renal function, haematocrit, size and side of tumour, the percentage of exophytic tumours, and the likelihood of more than one comorbidity. Surgical outcomes between the groups were also relatively similar. The length of stay, creatinine and haematocrit levels after surgery did not differ between the groups. The LPN group had a significantly longer operation (248 vs 152 min, P < 0.001) and higher EBL (222 vs 59 mL, P = 0.007) than the LCA group, but only one patient required a transfusion and there was no discernible difference in discharge haematocrit values. No recurrences were detected in either group, with a similar mean follow-up of 9.8 and 11.9 months, respectively. CONCLUSION: Although this matched-cohort comparison showed that LPN had a higher mean EBL, a longer operation and higher relative risk of open conversion, the overall clinical outcome was similar in terms of complication rates, length of stay and changes in creatinine and haematocrit after surgery. In this small retrospective evaluation, there was similar morbidity, treatment outcome and short-term efficacy with LCA and LPN. At present, although still experimental, LCA is a good choice for elderly patients with comorbidities precluding blood loss or renal ischaemia. However, in experienced hands, LPN is a preferred option for most elderly patients and should be considered when contemplating definitive treatment of renal masses

BACKGROUND: Neutral endopeptidase (NEP) is a cell-surface peptidase that can regulate the activation of Akt kinase through catalytic-dependent and independent mechanisms. NEP expression is absent in approximately 50% of prostate cancers. The authors investigated whether NEP loss in vivo would result in Akt phosphorylation and potentially contribute to prostate cancer progression by examining the interaction of NEP, Akt, and phosphatase and tensin homolog (PTEN) in a prostate xenograft model and in clinical specimens from patients with prostate cancer. METHODS: Using a tetracycline-repressible expression system to express NEP in a tumor animal xenograft model, the effects of NEP were tested on tumor growth, Akt phosphorylation, and PTEN expression. The clinical relevance of NEP, phosphorylated Akt, and PTEN protein expression also was investigated in 204 patients who had undergone radical prostatectomy. RESULTS: The results indicated that the induction of NEP expression inhibited established xenograft tumor growth, diminished Akt phosphorylation, and increased PTEN protein levels. In humans, prostate cancers with complete loss of NEP expression were significantly more likely to express phosphorylated Akt (P = .02). Moreover, patients who had prostate cancers with concomitant loss of NEP and expression of phosphorylated Akt had an increased, independent risk of prostate-specific antigen (PSA) recurrence (P = .03). In the study cohort, loss of PTEN protein expression did not correlated significantly with phosphorylated Akt or with patients' clinical outcome. CONCLUSIONS: The findings from this investigation demonstrated that NEP loss leads to Akt activation and contributes to the clinical progression of prostate cancer

OBJECTIVES: To determine whether the discrepancy in the radiologic and pathologic size of renal cell carcinoma influences the final cancer stage. METHODS: Renal masses resected from December 1999 to September 2004 were identified using a pathologic database and compared by surgical accession number to an existing clinical renal tumor database to identify those T1 and T2 tumors for which radiologic and pathologic data were available. The tumor histologic features, maximal pathologic diameter, and maximal radiologic diameter were recorded. The percentage of tumor size reduction was then calculated using these data. RESULTS: Of the 236 renal cancers evaluated, 52% had regressed in size when comparing the pathologic and radiologic sizes. When stratified by histologic subtype, clear cell tumors regressed more often and to a greater degree than those that were chromophobe or papillary. Also, 15 organ-confined tumors were downstaged when comparing the maximal radiologic diameter and the maximal pathologic diameter, and 13 of these were clear cell tumors. CONCLUSIONS: A reduction in kidney tumor size is commonly observed at surgical resection because of a loss of blood flow to the tumor. This tumor size reduction has an impact on the final pathologic stage in organ-confined tumors for which size is the only criterion. The greatest tumor size reduction, and most frequent downstaging, was observed for conventional (clear cell) tumors. We believe this may explain, in part, the worse stage-stratified outcomes for clear cell tumors compared with other tumor types. We propose that renal cancer staging should be determined from accurate measurement of the radiologic size, rather than the pathologic size