Biologic differences between noninvasive papillary urothelial neoplasms of low malignant potential and low-grade (grade 1) papillary carcinomas of the bladder

Combining two grading systems: the clinical validity and inter-observer variability of the 1973 and 2004 WHO bladder cancer classification systems assessed in a UK cohort with 15 years of prospective follow-up

Purpose

Paucity of reliable long-term data on the prognostic implications of the 2004 WHO bladder cancer classification system necessitates utilisation of both this and the 1973 grading systems. This study evaluated, in noninvasive (pTa) bladder tumours, the prognostic value of the 2004 system independently and in combination with the 1973 system while establishing concordance between tertiary centre uropathologists.

Methods

We used a cohort of non-muscle invasive bladder cancer (NMIBC) patients diagnosed between 1991 and 93 where tumour features were gathered prospectively with detailed cystoscopic follow-up data recorded over 15 years. Initial grading was by one senior expert uropathologist (UP1) using the 1973 WHO classification alone. Subsequently, two other expert uropathologists (UP2 and UP3), blinded to the previous grading, re-evaluated the pathology slides and graded the tumours using both the 1973 and 2004 systems. Association between grade and recurrence/progression was analysed and the Cohen Kappa test assessed concordance between pathologists.

Results

Of 370 new NMIBC, 229 were staged noninvasive (pTa). Recurrence rates were 46.2% and 50.0% for LGPUC (low-grade papillary urothelial carcinoma) and HGPUC (high-grade papillary urothelial carcinoma), respectively, while progression was seen in 3.9% and 10.0% of LGPUC and HGPUC, respectively. Concordance between uropathologists UP2 and UP3 for the 2004 and 1973 systems was good (Kappa = 0.69) and fair (Kappa = 0.25), respectively.

Conclusions

With good inter-observer concordance, the 2004 WHO classification system of noninvasive bladder tumours appears to accurately predict recurrence and progression risks. The combination of both grading systems to low-grade tumours allows further refinement of the natural history.

Bladder Urothelial Carcinoma in a Child: Case Report and Review of Literature

Bladder urothelial carcinoma (UC) it is the fifth most prevalent carcinoma in humans, nevertheless in children and young adults it's very rare. It usually occurs in older adults. Literature on UC in pediatric population is limited and important information (risk factors, follow-up protocols, etc.) are poorly defined. We present an 11-year-old boy with a painful macroscopic hematuria. Ultrasound revealed a heterogeneous intravesical mass without extravesical extension, which was confirmed by computed tomography (CT) and magnetic resonance imaging (MRI). The first biopsy was compatible with urothelial papilloma. After 1 year, he returned with a bigger mass. Transurethral resection of the bladder (TURB) was performed and immunohistochemistry showed low-grade papillary UC with a high-grade component, with tumor free margin. Tumor had mutations in the BRAF and KRAS genes. Two and a half years after the resection the patient has no recurrence. Less than 1% of bladder UC occur in the first two decades of life. Gross hematuria is a common symptom. Ultrasound is generally the first diagnostic tool. MRI is also helpful, but cystoscopy allows definitive diagnosis. Transurethral resection of the bladder (TURB) is the standard treatment, with good results and low recurrence rate, and it was the treatment of choice for our patient, that remains free of disease. The BRAF and KRAS gene mutations were never described before in pediatric UC. There are only few cases in literature of pediatric UC that present a tumor genetic profile; therefore, our case report adds more information to this very rare disease in children.

Papillary Urothelial Neoplasm of Low Malignant Potential (PUNLMP) After Initial TUR-BT: Comparative Analyses with Noninvasive Low-Grade Papillary Urothelial Carcinoma (LGPUC)

Purpose: To verify if the distinction between papillary urothelial neoplasm of low malignant potential (PUNLMP) and noninvasive low-grade papillary urothelial carcinoma (LGPUC) reflects a different biologic activity. Materials and Methods: We reviewed and analyzed the clinical data from 678 patients who had a diagnosis of PUNLMP (n=53) or noninvasive LGPUC (n=625) after initial TUR-BT for bladder neoplasm between 2000 and 2012. Results: The noninvasive LGPUC group showed a higher frequency of recurrence in comparison with the PUNLMP group (46.7% vs. 30.2%, p=0.022). In contrast, there were no significant differences in progression (15.2% vs. 18.9%, p=0.295) between the two groups. Grade progression was reported in 10 patients (LG: n=5; high grade: n=2; carcinoma in situ: n=3) and stage progression was reported in 2 patients (all: T1) in PUNLMP group. The Kaplan-Meier survival analysis showed significantly decreased 5-year recurrence-free survival (RFS) (50.3% vs. 74.6%, log-rank test, p=0.014) in the noninvasive LGPUC group compared to the PUNLMP group. However, there were no significant differences in progression-free survival (PFS) between the two groups. Multivariate analysis revealed that tumor grades according to 2004 WHO/ISUP classification system (PUNLMP vs. LG) were identified as significant predictors of RFS. However, it was not a significant predictor of both PFS and overall survival. Conclusions: PUNLMP had a substantial number of recurrences (30.2%), although RFS was better than noninvasive LGPUC. In addition, PUNLMP had a similar risk of progression compared with noninvasive LGPUC. Consequently, PUNLMP should be treated in a manner similar to noninvasive LGPUC, and long-term clinical follow-up should be recommended for patients with PUNLMP.

A Review of Outcomes for Stage Ta Bladder Tumors

OBJECTIVES

Using data from former reports, this study reviews and analyzes the outcomes of tumor recurrence, tumor progression, and tumor-specific survival of patients with stage Ta bladder tumors.

METHODS

Data were collected from 19 longitudinal studies of outcomes after the first diagnosis of tumor and collected as individual patient results, that is, as failure times from the first tumor to any of the three outcomes. Altogether, there were 14,252 patients, including 4,050 for the outcome of tumor recurrence, 2,937 for the outcome of tumor progression, and 11,595 for the outcome of disease-specific survival (some patients were available for more than one outcome).

RESULTS

In these data, the mean time to additional tumors was 7.8 years, the mean time to an invasive tumor was 19.5 years, and the mean tumor-specific survival time was 27.2 years. All three outcomes were significantly related to the 2004 World Health Organization (WHO) tumor grades.

CONCLUSIONS

Although greater than 50% of those with stage Ta bladder tumors have additional bladder tumors, approximately 80% appear to follow a benign course without developing invasive tumors or dying of bladder cancer. The 2004 WHO grading scheme accounts for some but not all of the prognostic information.

Immunohistochemical Differentiation between Urothelial Papillomas and Papillary Neoplasms of Low Malignant Potential of the Urinary Bladder

BACKGROUND

Urothelial papilloma and non-invasive papillary carcinoma are common neoplasms of the urinary bladder. Distinguishing papillomas and papillary carcinomas, especially the low grade type, is often debatable on the basis of histological features alone.

MATERIALS AND METHODS

We investigated immunohistochemical expression of cytokeratin 20 (CK20), p53, and Ki-67 in a group of 20 urothelial papilloma cases and 30 noninvasive papillary neoplasms of low malignant potential (PNLMP) of the urinary bladder. Whole tissue sections were examined.

RESULTS

Among the 30 carcinoma cases, 12 (40%) showed strong reactivity for the whole panel, 16 (53%) reacted positively for two markers, and 2 (7%) reacted just to one of them. Ki-67 was considered positive in 27 cases (90%) and p53 in 24 (80%), CK20 showed positive reactivity in 21 cases (70%). Only small percentages of papillomas were positive, and then only weakly.

CONCLUSIONS

We concluded that the intense positivity of suspicious cells for at least one of these markers would confirm the presence of malignant changes and favours the diagnosis of carcinoma.

Differences in Expression of Uroplakin III, Cytokeratin 7, and Cyclooxygenase-2 in Canine Proliferative Urothelial Lesions of the Urinary Bladder

The expression of immunohistochemical markers that have been used in diagnosis and/or prognostication of urothelial tumors in humans (uroplakin III [UPIII], cytokeratin 7 [CK7], cyclooxygenase-2 [COX-2], and activated caspase 3) was evaluated in a series of 99 canine proliferative urothelial lesions of the urinary bladder and compared to the lesion classification and grade as defined by the World Health Organization / International Society of Urologic Pathology consensus system. There were significant associations between tumor classification and overall UPIII pattern ( P = 1.49 × 10–18), loss of UPIII ( P = 1.27 × 10–4), overall CK7 pattern ( P = 4.34 × 10–18), and COX-2 pattern ( P = 8.12 × 10–25). In addition, there were significant associations between depth of neoplastic cell infiltration into the urinary bladder wall and overall UPIII pattern ( P = 1.54 × 10–14), loss of UPIII ( P = 2.07 × 10–4), overall CK7 pattern ( P = 1.17 × 10–13), loss of CK7 expression ( P = .0485), and COX-2 pattern ( P = 8.23 × 10–21). There were no significant associations between tumor classification or infiltration and caspase 3 expression pattern.

Biomarkers in bladder cancer: translational and clinical implications

Bladder cancer is associated with high recurrence and mortality rates. These tumors show vast heterogeneity reflected by diverse morphologic manifestations and various molecular alterations associated with these disease phenotypes. Biomarkers that prospectively evaluate disease aggressiveness, progression risk, probability of recurrence and overall prognosis would improve patient care. Integration of molecular markers with conventional pathologic staging of bladder cancers may refine clinical decision making for the selection of adjuvant and salvage therapy. In the past decade, numerous bladder cancer biomarkers have been identified, including various tumor suppressor genes, oncogenes, growth factors, growth factor receptors, hormone receptors, proliferation and apoptosis markers, cell adhesion molecules, stromal factors, and oncoproteins. Recognition of two distinct pathways for urothelial carcinogenesis represents a major advance in the understanding and management of this disease. Nomograms for combining results from multiple biomarkers have been proposed to increase the accuracy of clinical predictions. The scope of this review is to summarize the major biomarker findings that may have translational and clinical implications.

Prognostic significance of the 2004 WHO/ISUP classification for prediction of recurrence, progression, and cancer-specific mortality of non-muscle-invasive urothelial tumors of the urinary bladder: a clinicopathologic study of 1,515 cases

To verify prognostic significance of the 2004 World Health Organization (WHO)/International Society of Urological Pathology (ISUP) grading systems, we retrospectively studied the tumors of 1,515 patients who underwent transurethral resection of primary non-muscle-invasive urothelial tumors (pTa, 1,006 patients; pT1, 509 patients) confined to the bladder. Cases were classified according to the 2004 WHO/ISUP systems as 212 cases of papillary urothelial neoplasm of low malignant potential (PUNLMP), 706 low-grade papillary urothelial carcinomas (LPUCs), and 597 high-grade papillary urothelial carcinomas (HPUCs). PUNLMP showed the statistically significantly lowest recurrence cumulative incidence compared with the other tumor types. There were significant differences and trends for higher progression and cancer-specific mortality cumulative incidence in the following order: PUNLMP, LPUC, pTa HPUC, and pT1 HPUC. No differences of progression and cancer-specific mortality cumulative incidence were found between pTa and pT1 LPUC. Our study validates the usefulness of the 2004 WHO/ISUP system to classify urothelial tumors into prognostically distinct categories that would contribute to the design of therapeutic and monitoring strategies for patients with non-muscle-invasive bladder urothelial tumors.

Non-invasive papillary urothelial neoplasms: the 2004 WHO/ISUP classification system

The classification and grading of papillary urothelial neoplasms has been a long-standing subject of controversy. Previously, numerous diverse grading schemes for bladder tumor, including the 1973 World Health Organization (WHO) classification, existed whereby one of the major limitations was poor inter-observer reproducibility among pathologists. The WHO/International Society of Urological Pathology (ISUP) consensus classification system of urothelial neoplasms of the urinary bladder was developed in 1998 and was revised most recently in 2003 (published in 2004). Importantly, the current classification system provides detailed histological criteria for papillary urothelial lesions and allows for designation of a lesion (papillary urothelial neoplasm of low malignant potential) with a negligible risk of progression. Thus, the latest system is designed to be a universally acceptable one for bladder tumors that not only could be effectively used by pathologists, urologists, and oncologists, but also stratifies the tumors into prognostically significant categories. This article outlines the 2004 WHO/ISUP classification system regarding the specific histological criteria for non-invasive papillary urothelial neoplasms and the clinical significance of each category.

Phase I trial of oblimersen (Genasense®) and gemcitabine in refractory and advanced malignancies

BACKGROUND

Overexpression of Bcl-2 is associated with worse prognosis for a number of cancer types. The present study was designed to determine the maximum tolerated dose (MTD) of oblimersen (antisense Bcl-2) and gemcitabine when administered to patients with refractory malignancies.

MATERIALS AND METHODS

Sixteen patients with advanced solid tumors refractory to standard therapies were treated with escalating doses of oblimersen continuous, 120-h intravenous infusion given every 14 days, with a fixed-dose-rate intravenous infusion of gemcitabine administered on day 5 of each cycle. Serial plasma samples were collected to calculate the pharmacokinetics of oblimersen and gemcitabine, and also to measure the effect of oblimersen on Bcl-2 expression.

RESULTS

7 women and 9 men, median age 55 years (range 35-74 years), received a 5-day infusion of oblimersen at dose levels of 5 mg/kg/day (n = 4) or 7 mg/kg/day (n = 12). On the 5th day of the infusion, gemcitabine was given at 10 mg/m(2)/h for a total dose of 1,000 mg/m(2) (n = 7; cohorts I and II), 1,200 mg/m(2) (n = 3; cohort III), or 1,500 mg/m(2) (n = 6; cohort IV). Edema was the dose-limiting toxicity (DLT), necessitating expansion of cohort IV. No subsequent DLTs were noted. Thus, the maximum planned doses were well tolerated, and a formal MTD was not determined. Most hematologic toxicities were grade 1 or 2. There was low-grade fatigue, nausea/vomiting, and myalgias/arthralgias. Oblimersen C(ss) and AUC increased in relation to the dose escalation, but gemcitabine triphosphate levels did not correlate well with dose. There were no objective responses, though 5 patients had stable disease. A >75% reduction in Bcl-2 expression in peripheral blood mononuclear leucocytes was seen more frequently in patients who achieved stable disease than in progressing patients.

CONCLUSIONS

The maximal planned dose levels of oblimersen and gemcitabine in combination were well tolerated. Only one DLT (edema) occurred. There was a correlation between Bcl-2 reduction and stable disease. The recommended doses of the drugs for future studies are 7 mg/kg/day of oblimersen on days 1-5, and gemcitabine 1,500 mg/m(2) on day 5, every two weeks.

New Italian guidelines on bladder cancer, based on the World Health Organization 2004 classification

OBJECTIVE To provide evidence-based recommendations on bladder cancer management METHODS A multidisciplinary guideline panel composed of urologists, medical oncologists, radiotherapists, general practitioners, radiologists, epidemiologists and methodologists conducted a structured review of previous reports, searching the Medline database from 1 January 2004 to 31 December 2008. The milestone papers published before January 2004 were accepted for analysis. The level of evidence and the grade of the recommendations were established using the GRADE system. RESULTS In all, 15 806 references were identified, 1940 retrieved, 1712 eliminated (specifying the reason for their elimination) and 971 included in the analysis, as well as 241 milestone reports. A consensus conference held to discuss the discrepancies between the scientific evidence and the clinical practice was then attended by 122 delegates of various specialities. CONCLUSION Recommendations on bladder cancer management are provided.

Utility of a dual immunostain cocktail comprising of p53 and CK20 to aid in the diagnosis of non-neoplastic and neoplastic bladder biopsies

Background

Distinction between non-neoplastic and neoplastic bladder lesions is therapeutically and prognostically important. Our objective is to describe the use of double immunohistochemistry (DIHC) for p53+CK20 as a tool for diagnosing neoplasia in bladder biopsies.

Methods

p53+CK20 DIHC were examined in 38 reactive atypia, 10 dysplasia, 9 carcinoma in situ (CIS) and 7 invasive carcinoma (IC) cases. CK20 was evaluated according to distribution extent and degree of intensity whereas percentage of positive cells together with staining intensity was taken into account in the evaluation of p53.

Results

92% of reactive cases were either CK20(-) or (+) only in the upper 1/3 urothelium. In dysplastic cases CK20 staining distribution was as follows: 60% in 2/3 of the urothelium, 30% full thickness, 10% in the upper 1/3 urothelium. Among CIS cases, 89% had full thickness CK20 positivity, of which 62% were p53(+). 71% of IC cases exhibited strong and full thickness dual staining.

Conclusion

This is the first study in the literature to use DIHC of p53+CK20 in distinction of non-neoplastic and neoplastic bladder lesions. Dual staining by p53+CK20 cocktail allows for histologic correlation and diminishes the risk of losing the area of interest in limited biopsy specimens.

The current classification of urothelial neoplasms

The classification of urothelial neoplasms has been a subject of significant controversy and debate over the last decade. Only recently has a general level of agreement developed on the utility of the classification first proposed by the World Health Organization and the International Society of Urologic Pathology in 1998. Recent adoption of this scheme in therapeutic guidelines indicates the clinical utility of the system. In this review a brief historical perspective is presented, followed by a review of the classification system, the histological criteria for the specific categories and the clinical significance of these diagnoses.

[The 2004 WHO classification of bladder tumors: a summary and commentary]

The Key points of the latest World Health Organization (WHO) classification of non-invasive urothelial tumors are the following: the description of the categories has been expanded to improve their recognition: a tumor with particularly good prognosis (papillary urothelial neoplasm of low malignant potential) no longer carries the label of "cancer"; it avoids the use of ambiguous grading as grade 1/2 o 2/3 (as done in the 1973 WHO classification); the group of non-invasive high-grade carcinoma is large enough to virtually contain all those tumors having biological properties similar to those seen in invasive urothelial carcinoma, and a similarly high level of genetic instability. This scheme is meant to replace the 1973 WHO classification, but the use of both the 1973 and the latest WHO classification is recommended until the latter is sufficiently validated.

Strong immunohistochemical expression of fibroblast growth factor receptor 3, superficial staining pattern of cytokeratin 20, and low proliferative activity define those papillary urothelial neoplasms of low malignant potential that do not recur

BACKGROUND

Papillary urothelial neoplasm of low malignant potential (PUNLMP) is a clinically significant lesion because recurrence occurs in approximately 35% of patients. To date, it is not possible to identify those cases that will recur based on conventional histopathologic assessment. The objective of the current study was to evaluate immunohistochemically tissue expression of fibroblast growth factor receptor 3 (FGFR3), cytokeratin 20 (CK20), and MIB-1 in nonrecurrent and recurrent PUNLMP.

METHODS

FGFR3, CK20, and MIB-1 were investigated by immunohistochemistry (IHC) in 80 PUNLMP cases (41 nonrecurrent and 39 recurrent), in 4 cases of normal urothelium (NU), and in 5 cases of muscle invasive pT2 urothelial carcinoma (UC). Statistics included discriminant analysis.

RESULTS

NU demonstrated a weak to moderate FRFG3 staining intensity, a superficial pattern of CK20 staining, and low proliferative activity. UC was found to have FGFR3 staining similar to NU, an abnormal CK20 expression, and high proliferative activity. The nonrecurrent PUNLMP group demonstrated strong FGFR3 intensity in 80.5% of the cases (vs 56.4% of the recurrent cases), a superficial CK20 staining pattern in 53.7% of the cases (vs 28.2% of the recurrent cases), and a percentage of MIB-1-positive nuclei below the median value of all the PUNLMP cases in 61% of the cases (35.9% in the recurrent cases). The differences were statistically significant. Discriminant analysis based on these 3 features demonstrated that 67.5% of cross-validated grouped PUNLMP cases were correctly allocated, with 73.2% of the nonrecurrent and 61.5% of the nonrecurrent cases being correctly classified. The specificity and sensitivity were 73.1% and 61.5%, respectively.

CONCLUSIONS

Strong immunohistochemical expression of FGFR3, a superficial staining pattern of CK20, and a low proliferative activity define those papillary urothelial neoplasms of low malignant potential that do not recur.

Diagnostic algorithm for papillary urothelial tumors in the urinary bladder

Papillary urothelial neoplasms with deceptively bland cytology cannot be easily classified. We aimed to design a new algorithm that could differentiate between these neoplasms based on a scoring system. We proposed a new scoring system that enables to reproducibly diagnose non-invasive papillary urothelial tumors. In this system, each lesion was given individual scores from 0 to 3 for mitosis and cellular thickness, from 0 to 2 for cellular atypia, and an additional score for papillary fusion. These scores were combined to form a summed score allowing the tumors to be ranked as follows: 0–1 = UP, 2–4 = low malignant potential (LMP), 5–7 = low-grade transitional cell carcinoma (TCC), and 8–9 = high-grade TCC. In addition to the scoring system, ancillary studies of MIB and p53 indexes with CK20 expression pattern analyses were compared together with clinical parameters. The MIB index was strongly correlated with disease progression. Four of the 22 LMP patients (18.2%) had late recurrences, two of these four (9.1%) had progression to low-grade carcinoma. The MIB index for LMP patients was strongly associated with recurrence (recurrence vs. non-recurrence, 16.5 vs. 8.1, p < 0.001). The proposed scoring system could enhance the reproducibility to distinguish papillary urothelial neoplasms.

Survival Following the Diagnosis of Noninvasive Bladder Cancer: WHO/International Society of Urological Pathology Versus WHO Classification Systems

PURPOSE

The WHO/International Society of Urological Pathology classification of bladder cancer, introduced in 1998, differs from the traditional 1973 WHO classification. Few studies have reported survival data based on the WHO/International Society of Urological Pathology classification and none has demonstrated clear superiority compared to the 1973 WHO system. In a large, nonselected population of patients with bladder cancer we rated all incident tumors using each system and compared long-term patient survival.

MATERIALS AND METHODS

New Hampshire residents with bladder cancer diagnosed between 1994 and 2000 were identified through the State Cancer Registry. Slides were retrieved from more than 90% of cases and reviewed by a single pathologist. Tumors were classified according to WHO and WHO/International Society of Urological Pathology criteria. Overall patient survival was determined for the cohort of 504 patients after an average of 7 years using a national mortality database.

RESULTS

For both grading systems there was a gradient of progressively lower survival times from the lowest grade to the highest grade tumors. Hazard ratios and 95% confidence intervals for the WHO/International Society of Urological Pathology system were 1.9 (1.0-3.4) for low grade papillary urothelial carcinoma and 3.0 (1.5-6.0) for high grade papillary urothelial carcinoma, compared to papillary urothelial neoplasms of low malignant potential. For the WHO (1973) system compared to grade 1 tumors the hazard ratio for grade 2 tumors was 1.8 (1.1-3.1) and for grade 3 was 2.4 (1.2-4.7).

CONCLUSIONS

Advantages of the WHO/International Society of Urological Pathology bladder tumor classification include more detailed diagnostic criteria, the ability to define a lesion with minimal malignant potential and the ability to identify a larger group of patients needing closer surveillance. However, we found that the WHO/International Society of Urological Pathology tumor categories did not detect a clear overall survival advantage compared to the WHO (1973) classification system.

Comparison of 1998 WHO/ISUP and 1973 WHO classifications for interobserver variability in grading of papillary urothelial neoplasms of the bladder. Pathological evaluation of 258 cases

AIM

Our aim was to compare the interobserver variability between the 1998 WHO/ISUP and 1973 WHO classifications.

METHODS

258 consecutive papillary urothelial carcinomas were reviewed by two pathologists and assigned a tumor grade according to the 1973 WHO and 1998 WHO/ISUP without the knowledge of primary diagnosis and clinical follow-up. All cases were also histologically staged by the two pathologists separately as follows: pTa (noninvasive), pT1 (lamina propria invasion only), pT2 (muscularis propria invasion). Findings of both pathologists and degree of agreement were compared statistically by using Pearson's chi(2) test and kappa statistics respectively. A kappa value of 0.21-0.40 is accepted as fair, 0.41-0.60 moderate and 0.61-0.80 substantial agreement.

RESULTS

Regardless of the pathologist, tumor grades of two classifications correlated to each other and the pathological stage (p < 0.05). Overall degree of agreement between pathologists was higher in the 1998 WHO/ISUP (kappa 0.59) than the 1973 WHO (kappa 0.41), but both were still moderate. Papillary urothelial neoplasia with low malignant potential was the group of 1998 WHO/ISUP that showed the lowest degree of agreement and if excluded, interobserver variability of the 1998 WHO/ISUP decreased significantly (kappa 0.84).

CONCLUSION

The diagnosis of papillary urothelial neoplasia with low malignant potential and the criteria that differentiates it from low-grade carcinomas needs improvement in order to compare the different studies and therapies and to provide more accurate information for management.

Histologic Grading of Noninvasive Papillary Urothelial Neoplasms

OBJECTIVES

In 1998, a revised system of classifying noninvasive papillary urothelial neoplasms of the urinary bladder was proposed and subsequently formally adopted by the World Health Organization (WHO). The introduction of this new system was justified as being potentially superior on a number of levels to the 1973 WHO classification system that it replaced. Specifically, a new category of neoplasms, designated papillary urothelial neoplasm of low malignant potential (PUNLMP), was considered advantageous for several reasons. The new system was expected to gain widespread acceptance, improve reproducibility of diagnoses among pathologists, and enhance the correlation between urine cytology and tumor histology. We examine the history of the changes in terminology for these lesions, the relative merits of PUNLMP terminology, the extent to which the expectations accompanying the new grading system have been met, and the extent to which the new system has enhanced the management of patients with noninvasive papillary urothelial neoplasms of the bladder.

METHODS

A PubMed literature search after the introduction of this new classification was performed and relevant papers reviewed.

RESULTS AND CONCLUSIONS

The 2004 WHO classification is a positive initiative in attempting to standardize urothelial tumor grading by expanding and clearly defining the morphologic characteristics of noninvasive papillary urothelial neoplasms. The new terminology used in this system is of questionable validity and utility. Full-genome searches for prognostic and predictive molecular gene expression signatures, GeneChip technology and proteomics techniques, and several new biomarkers and molecular tests may be useful in future grading schemes after their clinical utility is better established.

Papillary Urothelial Neoplasm of Low Malignant Potential: Evolving Terminology and Concepts

PURPOSE

The most controversial aspect of the new WHO 2004/ISUP classification system is the creation of the PUNLMP diagnostic category. We discuss PUNLMP tumors and the WHO 2004/ISUP classification system with an emphasis on tumor morphology and heterogeneity, recurrence and progression rates, tumor genetics, interobserver variability and the usefulness of biomarkers and molecular diagnostic techniques for grading bladder tumors.

MATERIALS AND METHODS

A literature search using PubMed was performed. All relevant literature concerning PUNLMP and the WHO 2004/ISUP grading system for urothelial neoplasms was reviewed.

RESULTS

The new WHO 2004/ISUP classification reflects work in progress. Low malignant potential terminology may not reflect the true biological behavior of these tumors. Additionally, interobserver variability in making a diagnosis of PUNLMP is high despite detailed histological criteria. Urine cytopathology in the context of the WHO 2004/ISUP classification does not appear to effectively discriminate PUNLMP from low grade carcinoma.

CONCLUSIONS

For practical purposes patients with PUNLMP should be treated similarly to patients with low grade, noninvasive urothelial carcinoma. It is our hope that recent advances in the molecular grading of these tumors may eventually supplant traditional morphological classification, allowing a more precise and objective assessment of the biological potential of these tumors.

Bladder cancer: Epidemiology, staging and grading, and diagnosis

Bladder cancer is a heterogeneous disease with a variable natural history. At one end of the spectrum, low-grade Ta tumors have a low progression rate and require initial endoscopic treatment and surveillance but rarely present a threat to the patient. At the other extreme, high-grade tumors have a high malignant potential associated with significant progression and cancer death rates. In the Western world, bladder cancer is the fourth most common malignancy in men and the eighth most common in women. In Europe and the United States, bladder cancer accounts for 5% to 10% of all malignancies in men. The risk of developing bladder cancer at <75 years of age is 2% to 4% for men and 0.5% to 1% in women compared with the risk of lung cancer, for example, which is 8% in men and 2% in women. For the geographic and temporal comparison of bladder cancer incidence, it is crucial to separate the low-grade from the high-grade tumors. In epidemiologic studies on risk factors for bladder cancer, it is important to distinguish the low-grade Ta tumors from high-grade carcinoma in situ (CIS) and tumors >T1. Current studies do not support the routine screening for bladder cancer. However, prospective long-term studies are required to evaluate the benefits of bladder cancer screening, particularly in those at high risk. After assessing all available evidence, the Epidemiology and Diagnosis Committee has made recommendations on various diagnostic issues, including pathologic evaluation, urinary cytology, and imaging studies. Optimal resection techniques, role of repeat transurethral resection in high-grade T1 tumors, random bladder biopsy, and prostatic urethral biopsy are discussed, and appropriate recommendations are made according to the strength of available evidence.

The 2004 WHO classification of bladder tumors: a summary and commentary

The key points of the latest World Health Organization (WHO) classification of non-invasive urothelial tumors are the following: the description of the categories has been expanded to improve their recognition; a tumor with particularly good prognosis (papillary urothelial neoplasm of low malignant potential) no longer carries the label of 'cancer'; it avoids the use of ambiguous grading such as grade 1/2 or 2/3 (as done in the 1973 WHO classification); the group of noninvasive high-grade carcinoma is large enough to virtually contain all those tumors having biological properties similar to those seen in invasive urothelial carcinoma, and a similarly high level of genetic instability. This scheme is meant to replace the 1973 WHO classification, but the use of both the 1973 and the latest WHO classifications is recommended until the latter is sufficiently validated.

Karyometry detects subvisual differences in chromatin organisation state between non-recurrent and recurrent papillary urothelial neoplasms of low malignant potential

AIM

To analyse nuclear chromatin texture in non-recurrent and recurrent papillary urothelial neoplasms of low malignant potential (PUNLMPs).

MATERIALS

Ninety three karyometric features were analysed on haematoxylin and eosin stained sections from 20 PUNLMP cases: 10 from patients with a solitary PUNLMP lesion, who were disease free during at least eight years' follow up, and 10 from patients with unifocal PUNLMP, one or more recurrences being seen during follow up.

RESULTS

Kruskal-Wallis analysis was used to search for features showing significant differences between recurrent and non-recurrent cases. Significance was better than p<0.005 for more than 20 features. Based on significance, six texture features were selected for discriminant analysis. Stepwise linear discriminant analysis reduced Wilk's lambda to 0.87, indicating a highly significant difference between the two multivariate data sets, but only modest ability to discriminate (70% correct case classification). A box sequential classifier was used based on data derived from discriminant analysis. The classifier took three classification steps and classified 19 of the 20 cases correctly (95% correct case classification). To determine whether significant case grouping could also be obtained based on an objective criterion, the merged data sets of non-recurrent and recurrent cases were submitted to the unsupervised learning algorithm P-index. Two clusters were formed with significant differences. The subsequent application of a Cooley/Lohnes classifier resulted in an overall correct case classification rate of 85%.

CONCLUSIONS

Karyometry and multivariate analyses detect subvisual differences in chromatin organisation state between non-recurrent and recurrent PUNLMPs, thus allowing identification of lesions that do or do not recur.

Papillary urothelial neoplasm of low malignant potential: reliability of diagnosis and outcome

OBJECTIVE

To determine the ability of pathologists to reproducibly diagnose a newly defined lesion, i.e. the papillary urothelial neoplasm of low malignant potential (PUNLMP) using the published criteria, defined by the 1998 World Health Organisation/International Society of Urological Pathology (WHO/ISUP) classification system; in addition, debate remains about the clinical behaviour of these lesions, thus the rates of recurrence and progression of PUNLMP lesions were assessed and compared with low-grade papillary urothelial carcinomas (LG-PUC) and high-grade (HG-PUC) over a 10-year follow-up.

PATIENTS AND METHODS

Forty-nine cases of superficial bladder cancer (G1-3 pTa) representing an initial diagnosis of transitional cell carcinoma made in 1990 were identified and re-graded using the 1998 WHO/ISUP classification by two pathologists. Inter-observer agreement was assessed using Cohen weighted kappa statistics. After re-classification the clinical follow-up was reviewed retrospectively, and episodes of recurrence and progression recorded.

RESULTS

The inter-observer agreement was moderate, regardless of whether one (kappa 0.45) or two (kappa 0.60) pathologists were used to grade these lesions. Re-classification identified 12 PUNLMP, 28 LG-PUC and nine HG-PUC. PUNLMP lesions recurred in 25% (3/12) of cases; no progression was documented. Recurrence rates were 75% (21/28) and 67% (6/9) for LG- and HG-PUC, respectively, and progression rates were 4% (1/28) and 22% (2/9).

CONCLUSION

The 1998 WHO/ISUP classification of urothelial neoplasms can be reproducibly applied by pathologists, with a moderate level of agreement. There is evidence that PUNLMP lesions have a more indolent clinical behaviour than urothelial carcinomas. However, the risk of recurrence and progression remains, and clinical monitoring of these patients is important.

Ki67 expression in bronchial preneoplastic lesions and carcinoma in situ defined according to the new 1999 WHO/IASLC criteria: a preliminary study

AIMS

The World Health Organization classification of bronchial intraepithelial neoplastic lesions has been shown to be reproducible. However little is known about its biological value. The aim of this study was to assess the proliferative activity of mild (MiD), moderate (MoD), severe (SD) dysplasia and carcinoma in situ (CIS) by the expression of Ki67 on biopsy specimens obtained during fluorescence bronchoscopy.

METHODS AND RESULTS

The percentage of Ki67+ lesional nuclei was calculated in each lesion. In addition, the presence of Ki67 clusters (defined as a group of at least two strongly Ki67+ nuclei located in the upper third of the epithelium) and a Ki67 score were evaluated. The Ki67 score depended on the proportion of the stained nuclei and on the intensity of staining. MiD, MoD, SD and CIS showed increased Ki67 staining (respectively, 10%, 20%, 30% and 40% median values of positive cells). Thirty-one percent MiD, 77% MoD, 91% SD and 100% CIS showed one or more positive clusters. When only multiple clusters were considered the difference between high- and low-grade lesions was accentuated. Ki67+ clusters were more frequent in SD (91%) and CIS (94%) compared with MiD (15%) and MoD (22%). This difference was statistically significant (P < 0.01). Evaluation of the Ki67 score was in line with the above results: high grade lesions (SD and CIS) more often showed scores >4 (P = 0.05 between MiD plus MoD versus SD plus CIS).

CONCLUSIONS

Ki67 expression increases from MiD to CIS with a statistically significant difference between MiD plus MoD and SD plus CIS. These results suggest that, in terms of Ki67 positivity, SD behaves like CIS rather than like MiD or MoD.

The new World Health Organization/International Society of Urological Pathology (WHO/ISUP) classification for TA, T1 bladder tumors: is it an improvement?

The World Health Organization/International Society of Urological Pathology (WHO/ISUP) consensus classification of urothelial neoplasms of the urinary bladder was developed in an attempt to both improve upon prior classification systems as well as to adopt a classification system that would have widespread acceptance. Prior to this classification system, numerous diverse grading schemes for bladder cancer existed whereby the same lesion seen by different pathologists would result in very different diagnoses solely based on definitional differences of lesions. Another strength of the consensus classification system is that it provides detailed histological criteria for papillary urothelial lesions. In contrast, prior grading systems for bladder tumors were vague and subjective. The current classification system allows for designation of a lesion (papillary urothelial neoplasm of low malignant potential), which biologically has a very low risk of progression, yet is not entirely benign. In the past, these lesions were a source of controversy, as some experts in the field required very restrictive criteria for the diagnosis of papilloma and would label such lesions as malignant. Other experts in the field, not wanting to label a patient with such a low-grade papillary lesion as having carcinoma, would diagnose these lesions as papilloma. This intermediate category allows both schools of thought to diagnose a lesion as not fully malignant, yet still documents need for additional follow-up. Since its inception, several studies have been published documenting the relationship of tumors classified using the WHO/ISUP system to prognosis. These articles are summarized within this review.

Reproducibility and prognostic variability of grade and lamina propria invasion in stages Ta, T1 urothelial carcinoma of the bladder

PURPOSE

We assessed the reproducibility and prognostic variability of grade and lamina propria invasion in stages Ta, T1 urothelial carcinoma of the bladder.

MATERIALS AND METHODS

A total of 130 consecutive stages Ta, T1 urothelial carcinomas routinely diagnosed by 15 pathologists (original diagnosis) were reviewed by 3 independent experienced pathologists using 1999 WHO criteria (diagnoses 1 to 3 and reviewer consensus diagnosis). Interreviewer disagreement cases were blindly reviewed again. Each remaining disagreement case was discussed in a multihead microscope session to attempt to solve remaining disagreements. In cases of continuing disagreement the majority diagnosis on stage and grade was considered the consensus diagnosis. Stage progression at followup was the dependent variable. Stage progression-free Kaplan-Meier survival curves and hazard ratios of each stage and grade diagnosis were calculated and prognostic variability was determined.

RESULTS

There was complete interobserver agreement on stage and grade among reviewers in 80% and 59% of cases, while it was 87.7% and 75.4%, respectively, after the second review. More than 1 grade difference occurred in 1.5% of cases (0% after the second review). The consensus and original diagnoses agreed on stage and grade in 68.5% and 62.3% of cases, respectively. Assignment of individual cases to 1 category of the 1999 WHO classification per reviewer varied considerably. The incidence of cases classified as stage T1 grade 3 by the reviewers was between 12.3% and 18.9% (average 14.1%). Consensus diagnosis grade had the strongest prognostic value (HR 68.8, range 8.9 to 528.0). Of the 63 original diagnoses of stage T1 tumors the consensus diagnosis down staged 35 (55.6%) to Ta and up staged 8 (12.7%) to T2-3. Progression was more common in the 20 consensus diagnosis stage T1 cases (5 or 25%) than in the 55 original diagnosis stage T1 cases (11 or 20%). Original diagnosis stage T1 tumors that were down staged by the consensus diagnosis showed less progression than consensus diagnosis confirmed stage T1 tumors (17% versus 25%). The prognostically worst subgroup (T1 grade 3) also showed considerable prognostic variation among reviewers (28% to 76% at 5 years of followup), in that the consensus diagnosis again had the highest prognostic significance (HR 3.5, range 1.2 to 10.2). At the end of the study all pathologists expressed that they were regularly uncertain about stage and grade assessment in an individual case in a considerable percent of all cases.

CONCLUSIONS

Observer prognostic variability in staging and grading is considerable with potentially strong implications for patients. Interobserver variation did not decrease using the new 1999 WHO grading classification.

Proliferative activity is the most significant predictor of recurrence in noninvasive papillary urothelial neoplasms of low malignant potential and grade 1 papillary carcinomas of the bladder

BACKGROUND

Recurrence of transitional cell carcinoma of the bladder cannot be predicted accurately by traditional criteria alone. This study examined the value of cell proliferative activity, morphometry, and expression of p53, c-erbB-2, and bcl-2 oncogenes in predicting recurrence of superficial papillary urothelial neoplasms of low malignant potential (LMP) and Grade 1 (G1) papillary carcinomas of the bladder.

METHODS

Sixty-two patients (mean age, 62 years) with newly diagnosed superficial pTa bladder tumors (19 LMP, and 43 G1) were analyzed retrospectively. All patients underwent transurethral resection (TUR). Median follow-up was 69 months. Serial sections from formalin-fixed, paraffin-embedded material at initial TUR were stained with monoclonal antibodies (MoAbs) DO7, CB11, and bcl-2-124. Cell proliferation was assessed by MIB-1 MoAb, the quantity of argyrophilic nucleolar organizer region-associated proteins (AgNORs), and mitotic count.

RESULTS

Of the 62 patients, 42 (67.7%) had one or more recurrences. Recurrence rates were higher in MIB-1 (P < 0.0001) and p53 immunopositive cases (P = 0.02), when the mitotic count was greater than 5 (P = 0.004), and in G1 carcinomas (P = 0.04). In univariate analysis, the disease-free period was shorter for MIB-1 (P < 0.0001) and p53 immunopositive (P = 0.0001) cases, for cases with high AgNOR quantity (P = 0.04), mitotic count greater than 5 (P = 0.01), and in G1 carcinomas (P = 0.002). In multivariate analysis, only MIB-1 immunoreactivity retained independent prognostic significance.

CONCLUSIONS

Despite the small cohort, the results confirm the prognostic value of cell proliferation and p53 expression in patients with bladder neoplasms. The results also indicate that MIB-1 immunopositivity is the most significant predictor of recurrence and disease-free survival in superficial LMP and G1 papillary bladder carcinomas.