Value of separate tumor base biopsy in transurethral resection of bladder tumors.

INTRODUCTION: The aim of our study was to evaluate whether a biopsy from the tumor base after transurethral resection of bladder tumor (TURBT) has an impact on subsequent management of patients with bladder tumors. While tumor base biopsy at the completion of TURBT is a common practice, there is no definition of its role within the major international professional guidelines. MATERIAL AND METHODS: We retrospectively reviewed the records of consecutive patients undergoing TURBT between 2015 and 2019 at our institution. We recorded demographic and tumor characteristics of initial TURBT, tumor base biopsy and restaging TURBT pathology outcomes. The pathologic outcomes were correlated to assess the additional value of a separate tumor base biopsy. RESULTS: A total of 532 patients underwent TURBT. A separate tumor base biopsy after completion of TURBT was performed in 154 patients. The mean patient's age was 72.8 ±11.7 years (range 48-94) and 119 (77.2%) were men. In 40 patients (25.9%) muscle was absent in the pathological specimen of the tumor resection. Muscle was present in all but 6 (3.9%) tumor base biopsies. Of the 33 patients who underwent repeated transurethral resection for pT1 tumors, 2 had residual low-grade pTa, 1 had residual high-grade pT1, and 3 patients were upstaged to pT2. CONCLUSIONS: Although tumor base biopsy at the completion of TURBT is a common practice, our analysis fails to demonstrate any tangible benefit in the staging of bladder tumors. In our experience tumor base biopsy did not change the management in patients with superficial or muscle invasive disease.

Confident predictability: identifying reliable gene expression patterns for individualized tumor classification using a local minimax kernel algorithm.

BACKGROUND: Molecular classification of tumors can be achieved by global gene expression profiling. Most machine learning classification algorithms furnish global error rates for the entire population. A few algorithms provide an estimate of probability of malignancy for each queried patient but the degree of accuracy of these estimates is unknown. On the other hand local minimax learning provides such probability estimates with best finite sample bounds on expected mean squared error on an individual basis for each queried patient. This allows a significant percentage of the patients to be identified as confidently predictable, a condition that ensures that the machine learning algorithm possesses an error rate below the tolerable level when applied to the confidently predictable patients. RESULTS: We devise a new learning method that implements: (i) feature selection using the k-TSP algorithm and (ii) classifier construction by local minimax kernel learning. We test our method on three publicly available gene expression datasets and achieve significantly lower error rate for a substantial identifiable subset of patients. Our final classifiers are simple to interpret and they can make prediction on an individual basis with an individualized confidence level. CONCLUSIONS: Patients that were predicted confidently by the classifiers as cancer can receive immediate and appropriate treatment whilst patients that were predicted confidently as healthy will be spared from unnecessary treatment. We believe that our method can be a useful tool to translate the gene expression signatures into clinical practice for personalized medicine.

Transperitoneal laparoscopic radical nephrectomy is an effective procedure for large (more than 7 cm) renal masses.

PURPOSE: We aimed to evaluate our experience with the transperitoneal radical nephrectomy (TLRN) in patients with large (more than 7 cm) renal mass to determine if this procedure can be recommended as a reference standard for treating large renal masses. PATIENTS AND METHODS: Of 213 patients who underwent TLRN in both institutions we have reviewed medical files of 35 who had large than 7 cm renal masses. Operative time, blood loss, conversion rate, pathologic tumor type, and oncologic outcome were evaluated. RESULTS: The mean tumor size was 10.1 cm (range: 7 to 19 cm). Mean blood loss during surgery was 388 mL (range: 150 to 600 mL). In 2 patients with 16 cm renal masses the operation was converted to hand-assisted technique as planned upon the surgery after ligation and transsection of the vascular pedicel to facilitate kidney dissection from surrounding tissue. In 1 patient the operation was converted to the open technique. Twenty-two (62.8%) patients had renal cell carcinoma and the remaining 13(37.5%) patients had other types of the renal tumors. Mean hospital stay was 4.36 days (range: 3 to 7 d). Median follow-up after the surgery was 29 months (range: 8 to 60 mo). Three patients who underwent cytoreduction nephrectomy died whereas receiving immunotherapy 3, 8, and 11 months, respectively, after surgery. One patient developed a local tumor recurrence and 2 developed remote metastasizes. CONCLUSIONS: Our data show that TLRN is an effective procedure for the removal larger than 7 cm renal tumors. In those patients with exceptionally big tumors planned conversion to the hand-assisted technique after laparoscopic ligation of the renal vessels enabling easier renal dissection whereas preserving the advantages of minimally invasive procedure.