Comparing Robotic-Assisted to Open Radical Cystectomy in the Management of Non-Muscle-Invasive Bladder Cancer: A Propensity Score Matched-Pair Analysis.

BACKGROUND: For non-muscle-invasive bladder cancer (NMIBC) requiring radical surgery, limited data are available comparing robotic-assisted radical cystectomy with intracorporeal urinary diversion (iRARC) to open radical cystectomy (ORC). The objective of this study was to compare the two surgical techniques. METHODS: A multicentric cohort of 593 patients with NMIBC undergoing iRARC or ORC between 2015 and 2020 was prospectively gathered. Perioperative and pathologic outcomes were compared. RESULTS: A total of 143 patients operated on via iRARC were matched to 143 ORC patients. Operative time was longer in the iRARC group (p = 0.034). Blood loss was higher in the ORC group (p < 0.001), with a consequent increased post-operative transfusion rate in the ORC group (p = 0.003). Length of stay was longer in the ORC group (p = 0.007). Post-operative complications did not differ significantly (all p > 0.05). DFS at 60 months was 55.9% in ORC and 75.2% in iRARC with a statistically significant difference (p = 0.033) found in the univariate analysis. CONCLUSION: We found that iRARC for patients with NMIBC is safe, associated with a lower blood loss, a lower transfusion rate and a shorter hospital stay compared to ORC. Complication rates were similar. No significant differences in survival analyses emerged across the two techniques.

Differences in atrial substrate localization using late gadolinium enhancement-magnetic resonance imaging, electrogram voltage, and conduction velocity: a cohort study using a consistent anatomical reference frame in patients with persistent atrial fibrillation.

AIMS: Electro-anatomical voltage, conduction velocity (CV) mapping, and late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) have been correlated with atrial cardiomyopathy (ACM). However, the comparability between these modalities remains unclear. This study aims to (i) compare pathological substrate extent and location between current modalities, (ii) establish spatial histograms in a cohort, (iii) develop a new estimated optimized image intensity threshold (EOIIT) for LGE-MRI identifying patients with ACM, (iv) predict rhythm outcome after pulmonary vein isolation (PVI) for persistent atrial fibrillation (AF). METHODS AND RESULTS: Thirty-six ablation-naive persistent AF patients underwent LGE-MRI and high-definition electro-anatomical mapping in sinus rhythm. Late gadolinium enhancement areas were classified using the UTAH, image intensity ratio (IIR >1.20), and new EOIIT method for comparison to low-voltage substrate (LVS) and slow conduction areas <0.2 m/s. Receiver operating characteristic analysis was used to determine LGE thresholds optimally matching LVS. Atrial cardiomyopathy was defined as LVS extent ≥5% of the left atrium (LA) surface at <0.5 mV. The degree and distribution of detected pathological substrate (percentage of individual LA surface are) varied significantly (P < 0.001) across the mapping modalities: 10% (interquartile range 0-14%) of the LA displayed LVS <0.5 mV vs. 7% (0-12%) slow conduction areas <0.2 m/s vs. 15% (8-23%) LGE with the UTAH method vs. 13% (2-23%) using IIR >1.20, with most discrepancies on the posterior LA. Optimized image intensity thresholds and each patient's mean blood pool intensity correlated linearly (R2 = 0.89, P < 0.001). Concordance between LGE-MRI-based and LVS-based ACM diagnosis improved with the novel EOIIT applied at the anterior LA [83% sensitivity, 79% specificity, area under the curve (AUC): 0.89] in comparison to the UTAH method (67% sensitivity, 75% specificity, AUC: 0.81) and IIR >1.20 (75% sensitivity, 62% specificity, AUC: 0.67). CONCLUSION: Discordances in detected pathological substrate exist between LVS, CV, and LGE-MRI in the LA, irrespective of the LGE detection method. The new EOIIT method improves concordance of LGE-MRI-based ACM diagnosis with LVS in ablation-naive AF patients but discrepancy remains particularly on the posterior wall. All methods may enable the prediction of rhythm outcomes after PVI in patients with persistent AF.

Age represents the main driver of surgical decision making in patients candidate to radical cystectomy.

BACKGROUND AND OBJECTIVES: Age might influence the choice of surgical approach, type of urinary diversion (UD) and lymph node dissection (LND) in patients candidate to radical cystectomy (RC) for urothelial bladder cancer (UBC). Similarly, age may enhance surgical morbidity and worsen perioperative outcomes. We tested the impact of age (octogenarian vs. younger patients) on surgical decision making and peri- and postoperative outcomes of RC. METHODS: Non-metastatic muscle-invasive UBC patients treated with RC at 18 high-volume European institutions between 2006 and 2021 were identified and stratified according to age (≥80 vs. <80 years). Intraoperative Complications Assessment and Reporting with Universal Standards and European Association of Urology guidelines recommendations were accomplished in collection and reporting of, respectively, intraoperative and postoperative complications. Multivariable logistic regression models (MVA) tested the impact of age on outcomes of interest. Sensitivity analyses after 1:3 propensity score matching were performed. RESULTS: Of 1955 overall patients, 251 (13%) were ≥80-year-old. Minimally invasive RC was performed in 18% and 40% of octogenarian and younger patients, respectively (p < 0.001). UD without bowel manipulation (ureterocutaneostomy, UCS) was performed in 31% and 7% of octogenarian and younger patients (p < 0.001). LND was delivered to 81% and 93% of octogenarian and younger patients (p < 0.001). At MVA, age ≥80 years independently predicted open approach (odds ratio [OR]: 1.55), UCS (OR: 3.70), and omission of LND (OR: 0.41; all p ≤ 0.02). Compared to their younger counterparts, octogenarian patients experienced higher rates of intraoperative (8% vs. 4%, p = 0.04) but not of postoperative complications (64% vs. 61%, p = 0.07). At MVA, age ≥80 years was not an independent predictor of length of stay, intraoperative or postoperative transfusions and complications, and readmissions (all p values >0.1). These results were replicated in sensitivity analyses. CONCLUSIONS: Age ≥80 years does not independently portend worse surgical outcomes for RC. However, octogenarians are unreasonably more likely to receive open approach and UCS diversion, and less likely to undergo LND.

Reproducibility analysis of the computerized tomography angiography-derived left atrial wall thickness maps.

BACKGROUND: Adapting the ablation index (AI) to the left atrial wall thickness (LAWT) derived from computed tomography angiography (CTA) allows for a personalized approach that showed to improve PVI safety and outcomes. METHODS: Three observers with different degrees of experience performed complete LAWT analysis of CTA for 30 patients and repeated the analysis for 10 of these patients. Intra- and inter-observer reproducibility of these segmentations was assessed. RESULTS: Geometric congruence of repeated reconstruction of LA endocardial surface showed that 99.4% of points in the 3D reconstructed mesh were within < 1 mm distance for the intra-observer variability and 95.1% for the inter-observer. For the LA epicardial surface, an 82.4% of points were within < 1 mm for intra-observer and a 77.7% for inter-observer. A 1.99% of points were further than 2 mm for the intra-observer and a 4.1% for the inter-observer. Colour agreement between LAWT maps showed that a 95.5% and a 92.9% intra- and inter-observer respectively presented the same colour or a change to the colour immediately above or below. The ablation index (AI), which was adapted to this LAWT colour maps to perform a personalized pulmonary vein isolation (PVI), showed an average difference in the derived AI lower than 25 units in all cases. For all analyses, the concordance increased with user-experience. CONCLUSION: Geometric congruence of LA shape was high, for both endocardial and epicardial segmentations. LAWT measurements were reproducible, increasing with user experience. This translated into a negligible impact in the target AI.

Do perioperative blood transfusions impact oncological outcomes of robot-assisted radical cystectomy with intracorporeal urinary diversion? Results from a large multi-institutional registry.

BACKGROUND: Blood transfusions (BT) have been associated with adverse oncologic outcomes in multiple malignancies including open radical cystectomy (ORC) for urothelial carcinoma of the bladder (UCB). Robot-assisted radical cystectomy (RARC) with intracorporeal urinary diversion (ICUD) delivers similar oncologic outcomes compared to ORC, yet with lower blood loss and reduced transfusions. However, the impact of BT after robotic cystectomy is still unknown. METHODS: This is a multicenter study including patients treated for UCB with RARC and ICUD in 15 academic institutions, between January 2015 and January 2022. BT were administered during surgery (intraoperative blood transfusions, iBT) or during the first 30 days after surgery (post-operative blood transfusions, pBT). The association of iBT and pBT with recurrence-free survival (RFS), cancer-specific survival (CSS) and overall survival (OS) were evaluated by univariate and multivariate regression analysis. RESULTS: A total of 635 patients were included in the study. Overall, 35/635 patients (5.51%) received iBT while 70/635 (11.0%) received pBT. After a mean follow-up of 23±18 months, 116 patients (18.3%) had died, including 96 (15.1%) from bladder cancer. Recurrence occurred in 146 patients (23%). iBT were associated with decreased RFS, CSS and OS (P<0.001) on univariate Cox analysis. After adjusting for clinicopathologic covariates, iBT were associated only with the risk of recurrence (HR: 1.7; 95% CI, 1.0-2.8, P=0.04). pBT were not significantly associated to RFS, CSS or OS on univariate and multivariate Cox regression models (P>0.05). CONCLUSIONS: In the present study, patients treated by RARC with ICUD for UCB have a higher risk of recurrence after iBT, yet no significant association with CSS and OS was found. pBT are not associated with worse oncological prognosis.

Comparison of various late gadolinium enhancement magnetic resonance imaging methods with high-definition voltage and activation mapping for detection of atrial cardiomyopathy.

AIMS: Atrial cardiomyopathy (ACM) is associated with increased arrhythmia recurrence rates after pulmonary vein isolation (PVI). We compare the most common left atrial (LA) late gadolinium enhancement magnetic resonance imaging (LGE-MRI)-methods [Utah-method and image intensity ratio (IIR)-methods] and endocardial voltage mapping for ACM-detection and outcome prediction after PVI for atrial fibrillation (AF). METHODS AND RESULTS: In this prospective observational study, 37 ablation-naive patients (66 ± 9 years, 84% male) with persistent AF underwent LA-LGE-MRI and high-definition voltage and activation mapping (2129 ± 484 sites) in sinus rhythm prior to PVI. The MRI-post-processing-analyses were performed by two independent expert laboratories. Arrhythmia recurrence was recorded within 12 months following PVI. The global ACM-extent was highly variable: median LA low-voltage substrate (LA-LVS) was 12.9% at <1.0 mV and 2.7% at <0.5 mV; median LA-LGE-extent using the Utah-method was 18.3% and 0.03-93.1% using the IIR-methods. The LA activation time was significantly correlated with LA-LVS (r = 0.76 at <0.5 mV and r = 0.82 at <1.0 mV, both P < 0.0001), but not with LA-LGE-extent. The highest regional matching between LA-LVS <0.5 mV and LA-LGE was found for the anterior wall in 57% of patients using the Utah-method and in 59% using IIR 1.20. The corresponding values for the posterior wall were 19% and 38%, respectively. Arrhythmia recurrence occurred in 15(41%) patients. Freedom from arrhythmia was significantly lower in those with LA-LVS ≥2 cm2 at 0.5 mV but not in those with LGE ≥20% (Utah-stages III and IV): 43% vs. 81%, P = 0.009 and 50% vs. 67%, P = 0.338, respectively. CONCLUSION: Comparison of the most common LA-LGE-MRI methods and endocardial voltage mapping revealed large discrepancies in global and regional ACM-extent.

Variant histologies in bladder cancer: Does the centre have an impact in detection accuracy?

OBJECTIVE: To compare the accuracy in detecting variant histologies (VH) at transurethral resection of bladder (TURB) and radical cystectomy (RC) specimen among tertiary referral centres, in order to investigate potential reasons of discrepancies from the pathological point of view. PATIENTS AND METHODS: Clinical and histopathological data of TURB specimen and subsequent cystectomy specimen of 3,445 RC candidate patients have been retrospectively collected from 24 tertiary referral centres between 1980 and 2021. VH considered in the analysis were pure squamous cell carcinoma, urothelial carcinoma with squamous differentiation, pure adenocarcinoma, urothelial carcinoma with glandular differentiation, micropapillary bladder cancer (BCa), neuroendocrine BCa, and other variants. The degree of agreement between TURB and RC concerning the identification of VH was expressed as concordance, classified according to Cohen's kappa coefficient. RESULTS: A VH was reported in 17% of TURB specimens, 45% of which were not confirmed in RC. The lowest concordance rate was reported for micropapillary BCa with 11 out of 18 (61%) centres reporting no agreement, whereas neuroendocrine BCa achieved the highest concordance rate with only 3 centres (17%) reporting no agreement. Our results shows that even among centres with the advantage of a referent uropathologist the micropapillary variant is characterized by scarce accuracy between TURB and RC. Differences in TURB specimen acquisition by the urologist and in sampling methods among different centres are the main limitations of the study. CONCLUSIONS: Accuracy of TURB in detecting VH is poor for certain VH, in particular for micropapillary BCa, with evident variation among centres. Novel diagnostic tools are required to better identify these VH and drive patients toward a personalized treatment.

Defining the Morbidity of Robot-Assisted Radical Cystectomy with Intracorporeal Urinary Diversion: Adoption of the Comprehensive Complication Index.

Background and Objective: The Clavien-Dindo Classification (CDC) only reports the postoperative complication of highest grade. It is thus of limited value for radical cystectomy, after which patients usually experience multiple complications. The Comprehensive Complication Index (CCI) is a novel scoring system, which incorporates all postoperative events in one single value. The study aimed to adopt the CCI for the evaluation of complications in patients undergoing robot-assisted radical cystectomy (RARC) with intracorporeal urinary diversion (ICUD) and explore its advantages in the analysis of the morbidity of RARC with ICUD. Patients and Methods: A multicentric cohort of 959 patients undergoing RARC+ICUD between 2015 and 2020, whose complications are encoded in local prospective registries. Postoperative complications at 30 days were assessed using both the CDC and CCI. The CCI was calculated using an online tool (assessurgery.com). Risk factors for overall, major complications (CDC ≥III), and CCI were evaluated using uni- and multivariable logistic and linear regressions. To analyze the potential advantage of using the CCI in clinical trials, a sample size calculation of a hypothetic clinical trial was performed using as endpoint reduction of morbidity with either the CDC or CCI. Results: Overall, 885 postoperative complications were reported in 507 patients (53%). The CCI improved the definition of postoperative morbidity in 22.6% of patients. Male sex and neobladder were associated with major complications and to a significant increase in CCI on adjusted regressions. In a hypothetical clinical trial, 80 patients would be needed to demonstrate a ten-point reduction in CCI, compared with 186 needed to demonstrate an absolute risk reduction of 20% in overall morbidity using the CDC. Conclusion: CCI improves the evaluation of postoperative morbidity by considering the cumulative aspect of complications compared with the CDC. Implementing the CCI for radical cystectomy would help reducing sample sizes in clinical trials. Clinical Trial Registration number: NCT03049410.

Continuing acetylsalicylic acid during Robotic-Assisted Radical Cystectomy with intracorporeal urinary diversion does not increase hemorrhagic complications: results from a large multicentric cohort.

OBJECTIVES: To evaluate whether continuing the antiplatelet drug acetylsalicylic acid≤100mg (ASA) during Robotic-assisted radical cystectomy (RARC) with intracorporeal urinary diversion (ICUD) increases the risk of peri-and postoperative hemorrhagic complications and overall morbidity. Indeed, guidelines recommend interrupting antiplatelet therapy before radical cystectomy; however, RARC with ICUD is associated to reduced estimated blood loss and blood transfusions compared to its open counterpart. METHODS: Data from a multicentric European database were analyzed. All participating centers maintained a prospective database of patients undergoing RARC with ICUD. We identified patients receiving antiplatelet therapy by acetylsalicylic acid ≤100mg. Patients were divided into three groups: those not taking acetylsalicylic acid (no-ASA), those where ASA was continued perioperatively (c-ASA) and those where ASA was interrupted perioperatively (i-ASA). Estimated blood loss and peri-and post-operative transfusions were recorded. Hemorrhagic complications, ischemic, thrombotic and cardiac morbidity was recorded and classified using the Clavien-Dindo score by a senior urologist. RESULTS: 640 patients were analyzed. Patients on acetylsalicylic acid were significantly older and had more comorbidities. No significant difference was found for estimated blood loss between no-ASA, c-ASA and i-ASA (280 vs. 300 vs. 200ml respectively; P = 0.09). Similarly, no significant difference was found for intraoperative (5% vs. 9% vs. 11%; P = 0.07) and postoperative transfusion rate (11% vs. 13% vs. 18%; P = 0.17). Higher ischemic complications were noted in the i-ASA group compared to no-ASA and c-ASA (4% vs. 0.6% vs. 1.4%; P = 0.03). On uni and multivariate logistic regression, continuing acetylsalicylic acid was not significantly associated to either major complications or post-operative transfusions. CONCLUSIONS: Peri-operative acetylsalicylic acid continuation in RARC with ICUD does not increase hemorrhagic complications. Interrupting acetylsalicylic acid peri-operatively may expose patients to a higher risk of ischemic events.

Impact of the antibiotic-cargo from MSNs on Gram-positive and Gram-negative bacterial biofilms.

Mesoporous silica nanoparticles (MSNs) are promising drug nanocarriers for infection treatment. Many investigations have focused on evaluating the capacity of MSNs to encapsulate antibiotics and release them in a controlled fashion. However, little attention has been paid to determine the antibiotic doses released from these nanosystems that are effective against biofilm during the entire release time. Herein, we report a systematic and quantitative study of the direct effect of the antibiotic-cargo released from MSNs on Gram-positive and Gram-negative bacterial biofilms. Levofloxacin (LVX), gentamicin (GM) and rifampin (RIF) were separately loaded into pure-silica and amino-modified MSNs. This accounts for the versatility of these nanosystems since they were able to load and release different antibiotic molecules of diverse chemical nature. Biological activity curves of the released antibiotic were determined for both bacterial strains, which allowed to calculate the active doses that are effective against bacterial biofilms. Furthermore, in vitro biocompatibility assays on osteoblast-like cells were carried out at different periods of times. Albeit a slight decrease in cell viability was observed at the very initial stage, due to the initial burst antibiotic release, the biocompatibility of these nanosystems is evidenced since a recovery of cell viability was achieved after 72 h of assay. Biological activity curves for GM released from MSNs exhibited sustained patterns and antibiotic doses in the 2-6 µg/mL range up to 100 h, which were not enough to eradicate biofilm. In the case of LVX and RIF first-order kinetics featuring an initial burst effect followed by a sustained release above the MIC up to 96 h were observed. Such doses reduced by 99.9% bacterial biofilm and remained active up to 72 h with no emergence of bacterial resistance. This pioneering research opens up promising expectations in the design of personalized MSNs-based nanotherapies to treat chronic bone infection.

Antibacterial effect of antibiotic-loaded SBA-15 on biofilm formation by Staphylococcus aureus and Staphylococcus epidermidis.

Staphylococcus aureus and Staphylococcus epidermidis are human pathogens involved in implant-related infections. During those diseases, they are able to form biofilms showing resistance to the effect of many different antibiotics. Drug delivery systems allow a local and effective delivery of antibiotics at high concentrations in the infected tissue without causing the cytotoxic effects commonly linked to systemic administration. We report the use of a porous ceramic biomaterial, such as SBA-15 loaded with antibiotics, to deliver them directly to the infected tissue. SBA-15 discs were loaded with Vancomycin, Rifampin and a combination of both, introduced in a suspension of S. aureus 15981 and S. epidermidis ATCC 35984 and incubated during 6 and 24 h. A statistically significant decrease in the biofilm density and the number of viable bacteria was detected for all antibiotics at 6 h in both bacteria. Rifampin showed an increase in the biofilm density and the number of viable bacteria at 24 h. No differences were detected between Vancomycin and the combination of antibiotics. S. epidermidis was more sensitive to the effect of the antibiotics than S. aureus. Here we have demonstrated that SBA-15 is able to act as an effective drug delivery system not only from a pharmaceutical point of view, but also from a biological one.

Molecular profiling of peripheral blood is associated with circulating tumor cells content and poor survival in metastatic castration-resistant prostate cancer.

The enumeration of circulating tumor cells (CTCs) in peripheral blood correlates with clinical outcome in castration-resistant prostate cancer (CRPC). We analyzed the molecular profiling of peripheral blood from 43 metastatic CRPC patients with known CTC content in order to identify genes that may be related to prostate cancer progression. Global gene expression analysis identified the differential expression of 282 genes between samples with ≥5 CTCs vs <5 CTCs, 58.6% of which were previously described as over-expressed in prostate cancer (18.9% in primary tumors and 56.1% in metastasis). Those genes were involved in survival functions such as metabolism, signal transduction, gene expression, cell growth, death, and movement. The expression of selected genes was evaluated by quantitative RT-PCR. This analysis revealed a two-gene model (SELENBP1 and MMP9) with a high significant prognostic ability (HR 6; 95% CI 2.61 - 13.79; P<0.0001). The combination of the two-gene signature plus the CTCs count showed a higher prognostic ability than CTCs enumeration or gene expression alone (P<0.05). This study shows a gene expression profile in PBMNC associated with CTCs count and clinical outcome in metastatic CRPC, describing genes and pathways potentially associated with CRPC progression.

Laparoscopic treatment and staging of early ovarian cancer.

STUDY OBJECTIVE: To review the laparoscopic staging procedure in a series of patients with early ovarian cancer and compare results with the literature. DESIGN: A prospective single-center study (Canadian Task Force classification II-2). SETTING: A hospital in Spain. PATIENTS: A total of 20 patients with apparent early stage ovarian cancer from January 2003 through November 2007. The histologic tumor types were epithelial tumors (18 patients) and dysgerminoma (2 patients). Among the epithelial tumors, 11 were invasive and 7 were borderline (3 serous and 4 mucinous). INTERVENTIONS: Comprehensive laparoscopic staging was performed in all patients according to the International Federation of Gynecology and Obstetrics guidelines. MEASUREMENTS AND MAIN RESULTS: Seventeen patients had previous adnexal surgery and diagnosis and surgical staging were performed in only 3 patients during the same surgery. The patients' median age was 42.8 years (range 16-67). Eight (40%) patients desired to maintain fertility and a conservative approach was performed for this group. Laparoscopic staging was completed in 19 (95%) patients. In 1 case, a conversion to laparotomy was necessary as the para-aortic lymphadenectomy was completed because of a vessel lesion that was repaired without difficulty. The median operative time was 223 minutes (range 180-320) for radical surgery and 188 minutes (range 120-240) for the conservative approach. The mean hospital stay was 3 days. Of the 20 total patients, 4 (20%) were upstaged. The median follow-up was 24.7 months (range 1-61), with a disease-free survival of 95% and an overall survival of 100%. One recurrence was observed. CONCLUSION: A comprehensive surgical staging procedure is clearly indicated in cases of early ovarian cancer and oncologic guidelines should be respected. The laparoscopic approach could be a valid alternative to laparotomy.

An update of anatomical references in total laparoscopic radical hysterectomy: from surgical anatomy to anatomical surgery.

STUDY OBJECTIVE: To evaluate laparoscopic dissection methodology for exposing the anatomical references necessary to achieve total laparoscopic radical hysterectomy. DESIGN: Retrospective single-center study. Video records of total laparoscopic radical hysterectomy were reviewed. The classic works of surgical anatomy and the most recent works on pelvic anatomy were used to elaborate anatomical references. (Canadian Task Force classification II-1). SETTING: Son Llátzer General Hospital of Palma de Mallorca, Spain. INTERVENTIONS: Videorecords of 40 consecutive total laparoscopic radical hysterectomy for cervical cancer were reviewed. MEASUREMENTS AND MAIN RESULTS: The surgical maneuvers of total laparoscopic radical hysterectomy necessary for identification of the anatomical references are described. CONCLUSIONS: Abdominal radical hysterectomy entails a series of surgical maneuvers with potential risk of bleeding and/or damage to pelvic structures. Many of these risks can be prevented, because the laparoscope enables precise surgical maneuvers in zones of difficult abdominal access. It is necessary to renew the classic concepts of surgical anatomy to adapt them to the operative mechanics of laparoscopy, which are closer to the characteristics of microsurgery than abdominal surgery.

A novel logistic model based on clinicopathological features predicts microsatellite instability in colorectal carcinomas.

High-frequency microsatellite instability has been reported to be associated with good prognosis in colorectal adenocarcinoma. However, methods to assess microsatellite instability (MIN) are based on genetic assays and are not ideally suited to most histopathology laboratories. The aim of the present study was to develop a model for prediction of MIN status in colorectal cancer based on phenotypic characteristics. Clinicopathological features of a cohort of 204 patients with primary colon cancer were retrospectively reviewed following predetermined criteria. Genetic assessment of MIN status was performed on DNA extracted from sections of formalin-fixed, paraffin-embedded specimens by testing a panel of 11 microsatellite markers. Logistic regression analysis generated a mathematical tool capable of identifying colorectal tumors displaying MIN status with a sensitivity of 77.8% and a specificity of 96.8%. Features associated with instability included the proximal location of the lesions, occurrence of solid and/or mucinous differentiation, absence of cribriform structures, presence of peritumoral Crohn-like reaction, expansive growth pattern, high Ki67 proliferative index, and p53-negative phenotype. This approach predicts microsatellite instability in colorectal carcinoma with an overall assigned accuracy of 95.1% and a negative predictive value of 97.8%. Implementation of this tool to routine histopathological studies could improve the management of patients with colorectal cancer, especially those presenting with stage II and III of the disease. It will also assist in identifying a subset of patients likely to benefit from adjuvant chemotherapy.

A novel multiplexing, polymerase chain reaction-based assay for the analysis of chromosome 18q status in colorectal cancer.

Chromosome 18q allelic loss has been reported to have prognostic significance in stage II colorectal carcinoma. We have developed a fluorescent multiplex polymerase chain reaction assay to analyze five microsatellite markers (D18S55, D18S58, D18S61, D18S64, and D18S69) for allelic loss at the long arm of chromosome 18. Amplicon detection and evaluation was accomplished by capillary electrophoresis using an ABI 310 genetic analyzer. Robustness of the assay when performed on DNA extracted from formalin-fixed, paraffin-embedded tissue sections was confirmed by analyzing its repeatability and reproducibility. Allelic loss was assessed in 61 stage II colorectal tumors and was detected in 58% (31 of 53) of tumors not showing instability. As part of the study, results of 207 previous polymerase chain reaction/polyacrylamide-based assays were re-evaluated by two independent observers to determine the degree of concordance of visual evaluation. In the case of stage II colorectal tumors, when electropherogram results were compared with those obtained from visual evaluation of the same markers after polyacrylamide gel electrophoresis, discrepancies between observers were detected in 16.4% of determinations. In conclusion, we have developed a robust and reliable assay for multiplexed loss of heterozygosity determination that improves assessment of chromosome 18q allelic loss in colorectal tumors processed as routine formalin-fixed, paraffin-embedded specimens.

Genetic and immunophenotype analyses of TP53 in bladder cancer: TP53 alterations are associated with tumor progression.

Altered p53 status is a frequent event in bladder cancer and reported to have prognostic significance. We studied the TP53 gene and its product in 76 patients affected with urinary bladder carcinomas by immunohistochemistry (mAb DO-7), polymerase chain reaction single-strand conformational polymorphism (exons 4-8) followed by direct sequencing of shifted bands, and loss of heterozygosity in 17p (p53CA). H-RAS mutations were also studied. The receiver operating characteristic curve and the logistic-regression analysis were used to evaluate the validity of immunohistochemistry in predicting TP53 mutations. A p53-positive nuclear phenotype was defined by a cutoff of 20% tumor cells being immunoreactive and was found in 23 cases, while TP53 mutations were detected in 22 cases, four of them with a negative p53 phenotype. TP53 deletions were identified in 23 cases. No H-RAS gene mutations were observed. There was a significant association between phenotype and genotype results. Moreover, a significant association was observed between p53 status and tumor stage and grade, being alterations more common in high-stage and high-grade tumors (both chi2 test; P < .01). Deletion of 17p significantly correlated with tumor stage (P < .01) and grade (P = .01), allelic losses being more common in advanced disease. Data from these studies suggest that genetic assays are necessary for the optimal determination of TP53 alterations, mainly in tumors with a p53 negative phenotype, and especially in early stage tumors for which p53 status may assist in determining its progression to invasive disease. Since p53 alterations are significantly associated to clinicopathological features of poor prognosis, the inclusion of both p53 phenotype and TP53 mutation status into a predictive panel of tumor markers for bladder cancer is recommended.

Lack of p53 nuclear immunostaining is not indicative of absence of TP53 gene mutations in colorectal adenocarcinomas.

Multiple studies using primary tumors have reported that alterations in p53 expression and detection of TP53 mutations are associated with clinical aggressiveness and poor response to specific therapies. However, there is no general agreement regarding the optimal technical approach to the analysis of p53. We have studied a series of 100 primary colorectal adenocarcinomas by immunohistochemistry with the monoclonal antibody PAb1801, and single-stranded conformation polymorphism (PCR-SSCP, exons 4-8) followed by direct sequencing of shifted bands. p53 Nuclear staining was undetectable (score 0) in 29 of 100 cases. However, gene mutations were detected in 15 of these cases, with all of these mutations leading to abnormal proteins. p53 Nuclear staining was detectable and scored as less than 10% tumor cells positive in 15 of 100 cases but was still considered to be displaying a p53-negative phenotype because the cut-off value for positivity was 10% positive tumor cells. Nevertheless, TP53 gene mutations were detected in 2 of these cases. p53 Nuclear immunoreactivities were detectable and scored as more than 10% tumor cells positive in 56 cases, considered the p53-positive phenotype. TP53 gene mutations were identified in 51 of these 56 cases. These results reveal that immunohistochemical assessment does not predict TP53 mutation status in colorectal adenocarcinoma, mainly in cases displaying absence of nuclear staining. It is thus concluded that molecular profiling should be conducted in parallel with immunophenotyping when analyzing colorectal tumors for p53 status.