The prognostic significance of selective nuclear morphometry in urinary bladder carcinoma

Clinical applications of graph neural networks in computational histopathology: A review

Pathological examination is the optimal approach for diagnosing cancer, and with the advancement of digital imaging technologies, it has spurred the emergence of computational histopathology. The objective of computational histopathology is to assist in clinical tasks through image processing and analysis techniques. In the early stages, the technique involved analyzing histopathology images by extracting mathematical features, but the performance of these models was unsatisfactory. With the development of artificial intelligence (AI) technologies, traditional machine learning methods were applied in this field. Although the performance of the models improved, there were issues such as poor model generalization and tedious manual feature extraction. Subsequently, the introduction of deep learning techniques effectively addressed these problems. However, models based on traditional convolutional architectures could not adequately capture the contextual information and deep biological features in histopathology images. Due to the special structure of graphs, they are highly suitable for feature extraction in tissue histopathology images and have achieved promising performance in numerous studies. In this article, we review existing graph-based methods in computational histopathology and propose a novel and more comprehensive graph construction approach. Additionally, we categorize the methods and techniques in computational histopathology according to different learning paradigms. We summarize the common clinical applications of graph-based methods in computational histopathology. Furthermore, we discuss the core concepts in this field and highlight the current challenges and future research directions.

Image and statistical analysis of melanocytic histology

AIMS

We applied digital image analysis techniques to study selected types of melanocytic lesions.

METHODS AND RESULTS

We used advanced digital image analysis to compare melanocytic lesions as follows: (i) melanoma to nevi, (ii) melanoma subtypes to nevi, (iii) severely dysplastic nevi to other nevi and (iv) melanoma to severely dysplastic nevi. We were successful in differentiating melanoma from nevi [receiver operating characteristic area (ROC) 0.95] using image-derived features, among which those related to nuclear size and shape and distance between nuclei were most important. Dividing melanoma into subtypes, even greater separation was obtained (ROC area 0.98 for superficial spreading melanoma; 0.95 for lentigo maligna melanoma; and 0.99 for unclassified). Severely dysplastic nevi were best differentiated from conventional and mildly dysplastic nevi by differences in cellular staining qualities (ROC area 0.84). We found that melanomas were separated from severely dysplastic nevi by features related to shape and staining qualities (ROC area 0.95). All comparisons were statistically significant (P < 0.0001).

CONCLUSIONS

We offer a unique perspective into the evaluation of melanocytic lesions and demonstrate a technological application with increasing prevalence, and with potential use as an adjunct to traditional diagnosis in the future.

Absence of prognostic value of nuclear shape factor analysis in colorectal carcinoma: relevance of interobserver and intraobserver variability

PURPOSE

Several retrospective studies, including our previous investigation, have shown a prognostic value of nuclear shape factor in colorectal carcinomas. This prospective study was designed to assess the reliability of nuclear shape factor determined by nuclear morphometry and to confirm its prognostic value.

METHODS

Ninety-eight patients who underwent colorectal carcinoma resection were prospectively enrolled. Measurement of nuclear shape factor was performed by using a computer-based image analysis system. Nuclear shape factor was defined as the degree of circularity of the nucleus (1.0 for a perfect circle and <1.0 for any other elliptical shape). The prognostic impact of nuclear shape factor on ten-year survival and the intraobserver and interobserver agreement were assessed.

RESULTS

The nuclear shape factor mean values by American Joint Committee on Cancer stage were: 0.73 (0.07) in Stage I, 0.74 (0.06) in Stage II, and 0.75 (0.05) in Stage III carcinomas (P = 0.78, ANOVA). The intraobserver agreement was poor for observer A (r = 0.28) and practically nonexistent for observer B (r = -0.004, Pearson correlation). The intraclass coefficient for interobserver agreement was practically nonexistent. No significant association between nuclear shape factor and ten-year survival was found.

CONCLUSIONS

Our prospective results, as opposed to our previous retrospective results, suggest that the reliability for nuclear shape factor morphometric analysis is very poor. We failed to confirm a prognostic value for nuclear shape factor in colorectal carcinoma.

Prediction of radiosensitivity in human bladder cell lines using nuclear chromatin phenotype

BACKGROUND

Nuclear texture analysis measures phenotypic changes in chromatin distribution within a cell nucleus, while the alkaline Comet assay is a sensitive method for measuring the extent of DNA breakage in individual cells. The authors aim to use both methods to provide information about the sensitivity of cells to ionizing radiation.

METHODS

The alkaline Comet assay was performed on six human bladder carcinoma cell lines and one human urothelial cell line exposed to gamma-radiation doses from 0 to 10 Gy. Nuclear chromatin texture analysis of 40 features was then performed in the same cell lines exposed to 0, 2, and 6 Gy to explore if nuclear phenotype was related to radiation sensitivity.

RESULTS

Comet assay results demonstrated that the cell lines exhibited different levels of radiosensitivity and could be divided into a radiosensitive and a radioresistant group at >6 Gy. Using stepwise discriminant analysis, a subset of important nuclear texture features that best discriminated between sensitive and resistant cell lines were identified A classification function, defined using these features, correctly classified 81.75% of all cells into their radiosensitive or radioresistant groups based on their pretreatment chromatin phenotype. Posttreatment chromatin changes also varied between cell lines, with sensitive cell lines showing a relaxed chromatin conformation following radiation, whereas resistant cell lines exhibited chromatin condensation.

CONCLUSIONS

The authors conclude that the alkaline Comet assay and nuclear texture methodologies may prove to be valuable aids in predicting the response of tumor cells to radiotherapy.

Comparison of DNA ploidy and nuclear morphometric parameters with the conventional prognostic factors in transitional cell carcinomas

Carcinomas of the bladder cause important problems of mortality and morbidity despite diagnostic and therapeutic improvements. A variety of grading systems has been developed to reflect the different biologic behavior and malignant potential of this heterogeneous neoplasm. However, these histologic grading systems are subjective and reproducibility is low. In this study, the nuclear morphometric features and DNA ploidy status of 86 cases of transitional cell bladder carcinomas have been studied using image analysis methods with different data selection methods in nucleus suspension to evaluate the relationship of these parameters with the conventional prognostic factors. The relationship between these parameters and likelihood of relapse has also been investigated. In conclusion, the mean nuclear area of the 10 largest nuclei and DNA ploidy status have been shown to be significantly correlated with conventional prognostic factors. Cytomorphometrically, a binary grading system seems more suitable for transitional cell carcinoma of the bladder. For superficial carcinomas, morphometric parameters and DNA ploidy analysis can be helpful in the separation of the patients into prognostically different groups.

Prognostic value of proliferative activity and nuclear morphometry for progression in TaT1 urothelial cell carcinomas of the urinary bladder

OBJECTIVES

To analyze the predictive power of Ki67 area% (Ki67), mitotic activity index (MAI), p53 area% (p53), and the mean area of the 10 largest nuclei (MNA10) for progression of stage in 195 primary consecutive TaT1 urothelial cell carcinomas of the urinary bladder.

METHODS

Ki67- and p53-positive versus negative nuclei, MAI, and MNA10 using motorized systematic random sampling morphometry were determined. Kaplan-Meier curves and multivariate survival analysis (Cox model) were used to assess the prognostic value of the quantitative and classic clinicopathologic risk factors (age, sex, stage, grade, carcinoma in situ, multicentricity).

RESULTS

Thirteen (6.7%) of the 195 patients had progression (0 [0%] of 36 low-risk, 1 [1.1%] of 85 intermediate-risk, and 12 [16.2%] of 74 high-risk patients). In univariate analysis (all variables), the strongest predictors with the highest hazard ratios were Ki67 (threshold 25.0%), MAI (threshold 30), and MNA10 (threshold 170 microm2). In multivariate analysis, the strongest independent combinations for progression--MNA10 (170 microm2) plus MAI (threshold 30) and MNA10 (threshold 170 microm2) plus Ki67 (threshold 25.0%)--overshadowed all other features. p53 was weaker but, combined with Ki67, still predicted progression fairly well. In the total group, the sensitivity, specificity, and positive and negative predictive values of MNA10-MAI and MNA10-Ki67 at the thresholds mentioned were 100%, 89%, 38%, and 100%, respectively. These feature combinations were also strongest prognostically in the high-risk treatment group.

CONCLUSIONS

The combined biomarkers MNA10-MAI or MNA10-Ki67 are accurate, well reproducible, and easy to assess progression predictors in all patients with TaT1 urothelial cell carcinomas, as well as in high-risk (bacille Calmette-Guérin-treated) patients.

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.

Grading the invasive component of urothelial carcinoma of the bladder and its relationship with progression-free survival

Although grading is valuable prognostically in pTa and pT1 papillary urothelial carcinoma, it is unclear whether it provides any prognostic information when applied to the invasive component in muscle-invasive carcinoma. The authors analyzed 93 cases of muscle-invasive urothelial carcinoma of the bladder treated with radical cystectomy for which follow-up information was available. Each case was graded using the Malmström grading system for urothelial carcinoma, applied to the invasive component. Pathologic stage, lymph node status, and histologic invasion pattern were also recorded and correlated with progression-free survival. Thirty-four cases (37%) were pT2, 40 (43%) were pT3, and 19 (20%) were pT4. Of the 77 patients who had a lymph node dissection at the time of cystectomy, 34 (44%) had metastatic carcinoma to one or more lymph nodes. The median survival for pT2, pT3, and pT4 stages was 85, 24, and 29 months, respectively (p = 0.0001). Lymph node-negative and lymph node-positive patients had a median survival of 63 and 23 months, respectively (p = 0.0001). Fifteen patients (16%) were graded as 2b and 78 patients (84%) were graded as 3. Median survival of patients graded as 2b was 34 months compared with 31 months for patients graded as 3 (p value not significant). Three invasive patterns were recognized: nodular (n = 13, 14%), trabecular (n = 39, 42%), and infiltrative (n = 41, 44%). The presence of any infiltrative pattern in the tumor was associated with a median survival of 29 months, compared with 85 months in tumors without an infiltrative pattern (p = 0.06). Pathologic T stage and lymph node status remain the most powerful predictors of progression in muscle-invasive urothelial carcinoma. In this group of patients histologic grade, as defined by the Malmström system and as applied to the invasive component, provided no additional prognostic information. An infiltrative growth pattern may be associated with a more dismal prognosis.

Stereological estimates of nuclear star volume and vessels as predictors of chemotherapy response in small cell carcinoma of the lung: a preliminary report

AIMS

This study was designed to evaluate the role of morphometric and clinical parameters in predicting chemotherapy responder patients with small cell carcinoma of the lung.

METHODS AND RESULTS

Morphometric studies were performed by means of point counting techniques. Forty-six patients were included in this study. Group 1 patients (n = 19) were those without response to chemotherapy; Group 2 (n = 27) was composed by patients with partial or complete response to chemotherapy. Logistic regression analysis was used to attain the best separation of non-responder from responder patients. Star volume of the nuclei and vessel were selected during the backward procedure as relevant variables to characterize the two groups of patients. The overall sensitivity of the model was 80.43%.

CONCLUSIONS

Our results indicate that histopathological data may help to predict the chemotherapy response in patients with small cell lung carcinoma, and encourage the use of morphometric procedures in histopathological analysis of this type of lung tumours.

Morphometric applications in anatomic pathology

The components of the cell and tissue changes in many diseases are variable and can therefore be quantified. Characterization of these quantitative changes provides data that is useful not only for making a definitive, cell- and tissue-based diagnosis of disease, but also for predicting the course of disease. The spectrum of changes found in malignant tumors, ie, cell grade, architecture, cellularity, extent of invasion, nature and extent of inflammatory reaction, exemplify this range of quantifiable features. The diagnosis and prognosis of nonneoplastic diseases, ie, myopathy and metabolic bone disease, can also be determined by quantitating tissue changes. Morphometry is the quantification of changes in the "objects" of tissues, ie, cells and organelles, and their organization, using quantitative evaluation tools. The principles of morphometry have been known for a century. With the increasing availability of affordable, powerful computer systems and increasingly flexible and user-friendly software has come easier ability to measure these changes. This article discusses the principles of morphometry with illustrations of types of analysis (ie, area fraction, object counting, shape and size analyses, and mutliparametric analyses) using examples of these applications with discussions of error sources and limitations of morphometry.

Nuclear morphometry for improved prediction of the prognosis of human bladder carcinoma

BACKGROUND

Histologic grade and clinical stage generally are used for estimating the prognosis of bladder carcinoma. However, both methods have been reported to have a rather low reproducibility and to be unsatisfactory for predicting the recurrence and progression of superficial bladder carcinoma. Recently, nuclear morphometry was used to quantitate the malignant potential of cancer cells in a more objective and reproducible manner. The authors quantitatively analyzed the malignant potential of bladder carcinoma at initial presentation using a combination of several nuclear morphometric variables.

METHODS

The subjects were 156 patients with previously untreated bladder carcinoma. Three morphometric variables were measured in each subject: the mean nuclear volume (MNV), the nuclear roundness factor (NRF), and the variation of nuclear area (VNA).

RESULTS

Univariate analysis showed that MNV and NRF were significant prognostic indicators for survival (MNV, P < 0.0001; NRF, P = 0.008). In addition, MNV was a prognostic indicator for tumor recurrence (P = 0.001), whereas MNV and NRF were prognostic indicators for invasive progression (MNV, P = 0.02; NRF, P = 0.009). For accurate prediction of the prognosis of patients with bladder carcinoma, a prognostic score, a recurrence score, and a progression score were designed using the coefficients of MNV and NRF in a proportional hazards model. The prognostic score clearly divided the patients into two different groups with 5-year survival rates of 88% and 64% (P = 0.0002). In addition, patients with superficial bladder carcinoma and a low recurrence score had a significantly higher 5-year recurrence free rate than those with a high recurrence score (40% vs. 23%, P = 0.0004), and the 5-year progression free rate of patients with a low progression score was significantly higher than that of those with a high progression score (98% vs. 73%, P = 0.0006).

CONCLUSIONS

These findings suggest that nuclear morphometry is a reliable technique with which to identify prognostic indicators for human bladder carcinoma. A combination of several nuclear morphometric variables provides a more accurate indication of prognosis than any single parameter.

The role of nuclear morphometry for predicting disease outcome in patients with localized renal cell carcinoma

BACKGROUND

More than one-third of patients with localized renal cell carcinoma (RCC) will have disease progression after nephrectomy. Present histopathologic variables cannot accurately predict the outcome of individual patients.

METHODS

Nuclear morphometry was performed by an image analyzer on histologic sections from 39 specimens of pathologic T1 and T2 classification RCC. All patients underwent radical nephrectomy and were followed for a mean of 7.6 years. A univariate analysis and then a multivariate stepwise regression method were used to correlate results with patients' outcome.

RESULTS

The best predictors of disease free interval were mean nuclear elongation factor (MNEF) (P = 0.023), mean nuclear regularity factor (MNRF) (P = 0.034), and mean nuclear area (MNA) (N = 0.038). Univariate analysis identified a significant correlation between patient survival and MNEF (P = 0.009), MNRF (P = 0.020) and MNA (P = 0.023). Combination of MNEF and MNA was even more strongly associated with survival (P = 0.0013). Multivariate analysis revealed that MNA (P = 0.044) and MNEF (P = 0.045) correlated independently with survival.

CONCLUSION

These results suggest that nuclear morphometry provides objective independent prognostic information for patients with localized RCC.

Il carcinoma uroteliale della vescica pT1G3. Studio clinico-patologico e morfometrico di 26 casi trattati con BCG: Urothelial bladder carcinoma pT1G3. Clinico-pathological and morphometric study of 26 cases treated with BCG

From 1987 to 1993, 26 patients with superficial urothelial bladder carcinoma pT1G3 were observed consecutively at the Dept. of Urology of Pordenone City Hospital and the Division of Pathology of the Centro di Riferimento Oncologico di Aviano (Italy). All patients were treated with TUR and then with a course of BCG-intravesical instillations. The complete immunoprophylaxis treatment consisted of a weekly instillation of BCG for 6 weeks; then cystoscopy and urinary cytologies or random biopsies were performed. An additional 1-monthly BCG treatment for 3 months was administered to 10 disease-free patients. In 6 cases of pT1G3 recurrences, a new complete cycle of BCG was performed whereas in 10 patients with local progression, defined as muscular infiltration, a cystoprostatectomy or RT therapy was advised. Follow-up examinations, planned every 3 months for 2 years and then every 6 months for 3 years, included cystoscopy and urinary cytologies in 19 patients and cystoscopy with randomized biopsies and washing in the remaining 7 patients. Ten patients were disease-free at a mean of 34 months follow-up (range 13-65 months); 6 patients experienced recurrence at a mean of 7 months follow-up (range 3-40 months) and 10 patients local progression at a mean of 13 months follow-up (range 3-44 months). The morphometric study demonstrated that cases with average nuclear area, in the deepest part of the histological section, more or equal to 40 μm2 have a threefold progression rate, compared to cases with average nuclear area less than 40 μm2 (p = 0.10). Our results would indicate the possible role of morphometric evaluation of prognostically important parameters, in the clinical management of patients with pT1G3 tumours.

Correlation of morphometry, nucleolar organizer regions, proliferating cell nuclear antigen and Ki67 antigen expression with grading and staging in urinary bladder carcinomas

OBJECTIVE

To investigate the correlation of four different indicators of proliferation--mean nuclear area (MNA) morphometry, nucleolar organizer region (NOR) count, proliferating cell nuclear antigen (PCNA) and Ki67 antigen expression--in specimens of invasive and non-invasive urinary bladder carcinomas with the grading and staging of the tumour and to determine which indicator is most suitable for discriminating between non-invasive and invasive carcinomas.

MATERIALS AND METHODS

Biopsies of 58 urinary bladder carcinomas of different grade and stage (38 invasive, 20 non-invasive) and 11 carcinomata in situ were included in the study. Ten specimens of normal bladder mucosa served as controls. Analysis of indicators was performed on sequential serial paraffin sections of the same tissue, applying each test once to one of four serial sections.

RESULTS

In comparison to normal bladder mucosa the values of the four indicators were significantly greater (P < 0.001) in all carcinomata in situ and in carcinomas. Values also increased from grade 1 to grade 3 carcinomas, but indicator values were similar for carcinomata in situ and grade 2 carcinomas. All indicators correlated with each other and allowed a significant discrimination between grade 1 and 2 or grade 2 and 3 carcinomas. Non-invasive carcinomas (Ta) showed a significantly lower proliferative activity (P < 0.001) than invasive carcinomas but there were overlapping values within the invasive carcinomas (T1,T2 and T3/4).

CONCLUSIONS

MNA, NOR count, PCNA index and Ki67 index could be correlated with tumour grade, but not with stage, of transitional bladder carcinoma. Of the indicators studied the Ki67 antigen was the most useful in differentiating between invasive and non-invasive carcinomas. This could be of prognostic relevance, especially for the heterogeneous group of grade 2 carcinomas.

The use of digital image analysis of chromatin texture in Feulgen-stained nuclei to predict recurrence of low grade superficial transitional cell carcinoma of the bladder

BACKGROUND

Identifying a marker enabling prediction of recurrence in the group of superficial transitional cell carcinomas (sTCCs) of the bladder remains an important challenge today. This report quantitatively describes chromatin patterns with respect to such sTCC recurrence.

MATERIALS AND METHODS

Twenty-nine patients with sTCCs who did not exhibit tumor recurrence within a minimum of 24 months were compared with 21 patients with sTCCs who exhibited tumor recurrence two or three times in a 24-month period, for a total of 74 sTCCs. Quantitative chromatin pattern description was performed by the digital cell image analyses of Feulgen-stained nuclei. Six morphonuclear parameters were thus described and subsequently used to determine a score, allowing biological behavior of sTCCs to be described, i.e., recurrence versus non-recurrence in one calculation step. DNA ploidy level was also determined in each sTCC by assessing its DNA histogram type.

RESULTS

Of 32 patients with Grade 1 pathologically classified pTa/pT1 tumors, DNA ploidy level determination permitted correct prediction of tumor nonrecurrence or recurrence of 13 (41%), whereas determination of the score values enabled prediction of nonrecurrence or recurrence of 25 (78%). Combining DNA ploidy level data and the score values enabled recurrence or nonrecurrence to be predicted for 29/32 of the patients (91%).

CONCLUSIONS

The quantitative description of chromatin patterns by digital cell image analysis of Feulgen-stained nuclei can provide helpful information, in addition to DNA ploidy level determination, in predicting tumor recurrence of low grade superficial transitional cell carcinomas of the bladder.

Nucleolar and argyrophilic nucleolar organizer region counts in urothelial carcinomas with special emphasis on grade II tumors

Prognostic assessment of bladder carcinomas of intermediate differentiation is difficult. This study therefore investigated the prognostic values of nucleolar status and silver staining of argyrophilic nucleolar organizer regions (AgNORs) in grade II bladder carcinomas. In biopsies from 34 grade II transitional cell carcinomas of the urinary bladder the number of nuclei with nucleoli, the location of nucleoli within the nucleus and the number of AgNORs were determined in 1000 or 200 nuclei per section respectively. Ten biopsies showing normal urothelium, 18 cases with mild to severe atypia, 27 grade I, 34 grade II and 12 grade III transitional cell carcinomas were also studied. Significantly differing nucleolar and AgNOR values were found comparing normal urothelium/grade I carcinomas with severe urothelial atypia/grade III carcinomas. Grade II carcinomas, however, were inhomogeneous. One subgroup had nucleolar and AgNOR values resembling grade I carcinomas while the second group had values similar to those of grade III carcinomas. This subdivision of grade II carcinomas correlates with results reported for DNA-cytometry. The results suggest a subdivision of patients with grade II transitional cell carcinomas into a low risk and high risk group.

Computerized nuclear morphometry and survival in renal cell carcinoma: comparison with other prognostic indicators

Morphometric nuclear parameters were compared with patient survival for a series of 174 renal cell carcinomas (RCC) collected over a 30 yr period. Stepdown regression showed long diameter, average feret diameter, form factor and the ratio of average feret diameter to equivalent diameter to be significantly associated with survival. Nuclear area, nuclear perimeter, equivalent diameter, ratio of long diameter to average feret diameter and coefficients of variation of nuclear area and nuclear perimeter were not significantly correlated with survival. All parameters were correlated with a 3 division nuclear grading classification using analysis of variance. Multivariate analysis showed nuclear form factor, tumor stage, silver staining nucleolar organizer region numbers and proliferating cell nuclear antigen expression to be independently associated with survival. The results of this study indicate that form factor is the most discriminate morphometric parameter for RCC, providing survival data additional to that derived from tumor staging and from markers of tumor proliferation.

Computer-assisted chromatin texture characterization of Feulgen-stained nuclei in a series of 331 transitional bladder cell carcinomas

The chromatin patterns of Feulgen-stained nuclei in a series of six specimens of normal mucosa and 331 transitional bladder carcinomas, including 293 superficial (Ta and T1) and 38 invasive (T2-T4) cases, were quantitatively described by means of eight parameters relating to densitometric, run-length distribution, and co-occurrence matrix features. The results show that the chromatin texture of the superficial lesions was markedly different from that of the invasive tumours, which exhibited a distinctly more dense and heterogeneous chromatin pattern. The data also show that the increasing level of malignancy, as revealed by the increasing clinical stage, was accompanied by an increase in the overall chromatin condensation level. Only some areas of the nucleus actually increased in density; other pale areas appeared concomitantly with these increasingly denser chromatin areas. This chromatin density increase corresponded to a marked increase in the frequency of small dense chromatin clumps; these joined together into very large dense chromatin clumps, which were distributed more and more heterogeneously in the nucleus as the clinical stage of the tumour increased.

Cell proliferation indices, morphometry and DNA flow cytometry provide objective criteria for distinguishing low and high grade bladder carcinomas

Argyrophilic nucleolar organizer region (Ag-NOR) analysis, proliferating cell nuclear antigen (PC-NA/PC10) and MIB-1 immunohistochemistry, nuclear morphometry and DNA flow cytometry have been performed on formalin-fixed, paraffin-embedded biopsies from 50 patients with transitional cell carcinoma of the urinary bladder. The mean AgNOR count was 6.01 for the 17 grade 1 (G1), 7.59 for the 21 G2 and 13.33 for the 12 G3 carcinomas (p < 0.001). The mean PCNA score was 15.03% for G1, 24.04% for G2 and 40.01% for G3 cases (p < 0.001). The mean MIB-1 score was 11.31% for G1, 17.09% for G2 and 34.47% for G3 carcinomas (p < 0.001). The mean nuclear area was 35.53 microns2 for G1, 38.65 microns2 for G2 and 83.62 microns2 for G3 cases (p < 0.001). Aneuploidy rates were significantly higher (91.7%) in G3 than in G2 (42.9%, p < 0.01) or G1 cases (47.1%, p < 0.05) but not different for G1 versus G2 cases (p = 0.94). While many overlaps of values were seen between G1 and G2 tumours, no overlaps were found between G3 and G1/G2 tumours. Significant differences of values were also found between pTa and invasive tumours (p < 0.0001 for AgNOR count and PCNA score; p < 0.001 for MIB-1 score and mean nuclear area; p < 0.01 for DNA ploidy); however many overlaps were seen. Our findings indicate that the quantitative parameters obtained with different methods are associated with histological grade of bladder urotheliomas and may improve the grading reproducibility. In addition, the absence of overlaps between G3 and G2/G1 carcinomas supports the tendency to classify bladder urotheliomas in only two categories of malignancy.

Quantitative histopathology in the prognostic evaluation of patients with transitional cell carcinoma of the urinary bladder

BACKGROUND

Morphologic grading of malignancy is considered to be of prognostic value in patients with transitional cell carcinomas of the urinary bladder (TCC). This qualitative approach is, however, associated with low reproducibility. Grading of malignancy can be carried out on a reproducible, quantitative scale.

METHODS

A retrospective, prognostic study of 110 patients treated for TCC in clinical Stages Ta-T4 (median follow-up time, 6 years) was performed, evaluating various grading techniques. Unbiased estimates of the volume-weighted mean nuclear volume (nuclear vV), nuclear volume fraction, estimates of nuclear mean profile area (aH(nuc)), nuclear profile density index (NI), and mitotic profile density index (MI) were obtained by stereologic and morphometric techniques.

RESULTS

The T-stage and morphologic grade of malignancy were closely cross-correlated (+0.63 < Kendall tau < +0.71, 2P < 6.7 x 10(-16)). The estimation of nuclear vV was highly efficient, with more than 85% of the associated variation attributable to differences between tumors. A positive significant correlation between estimates of nuclear vV and aH(nuc) was detected (r = +0.79), whereas an inverse correlation was documented between nuclear vV and NI (r = -0.63). Estimates of nuclear volume fraction showed no correlation with nuclear vV. Comparisons between categorical and quantitative data revealed the following: a decrease in averaged estimates of NI for tumors in advanced T-stage and malignancy grade (2P < 0.0008); and nuclear vV and aH(nuc) increased on average, in tumors of high T-stage and malignancy grade. Estimates of MI were also positively correlated with the T-stage and the malignancy grade (+0.42 < Kendall tau < +0.49). Single-factor analyses showed prognostic effect of T-stage, grade of malignancy, and, apart from nuclear volume fraction, all quantitative histopathologic variables with regard to overall survival (2P < 0.03). None of the morphometric and stereologic parameters were of prognostic values with regard to recurrence-free survival (2P > 0.26). Multiple hazards regression analysis (Cox models) revealed that clinical stage of disease was the sole independent prognostic variable. Only estimates of nuclear vV added significant independent prognostic prediction with regard to recurrence-free survival in the 48 patients with Ta tumors (2P = 0.03).

CONCLUSIONS

The results suggested that estimates of nuclear vV are prognostically superior to morphologic grading of malignancy in noninvasive TCC, whereas both morphologically and quantitatively based malignancy grading are without prognostic value in invasive TCC.

The use of nuclear morphometry in predicting recurrence of transitional cell carcinoma

Despite apparently adequate surgical resection, metastases develop in about 50% of the patients who undergo radical cystectomy for invasive bladder cancer and they die of disease within 2 years of surgery. Recent reports have shown that combination chemotherapy with regimens including cisplatin results in significant improvement in time to progression and overall survival for patients with transitional cell carcinoma. We have used quantitative nuclear morphometry in an effort to predict which individual patients with muscle invasive transitional cell carcinoma are at increased risk for recurrence and in need of adjuvant therapy. A total of 14 patients with deeply invasive tumors without known metastases (tumors, nodes and metastasis stage P3A-B, N-, M0) who had not received perioperative radiation or systemic chemotherapy was studied. Of the patients 7 (group 1) had no evidence of disease with a mean followup of 41 months and 7 (group 2) had recurrent transitional cell carcinoma at a mean followup of 17 months. Both groups were similar with respect to age and could not be distinguished by standard pathological analysis of stage (p = 0.66) or grade (p = 0.99). A total of 150 tumor nuclei from each patient was digitized and analyzed by a high resolution quantitative morphometric imaging system, developed in this laboratory, to determine if nuclear shape descriptors could separate these 2 clinically distinct groups. A multivariate analysis combining 3 independent nuclear shape descriptors (average nuclear area, minimum feret-diameter ratio and kurtosis of feret-diameter ratio) was highly significant (p = 0.003) and separated patients in group 1 from group 2 without overlap. These encouraging results suggest that nuclear morphometry may be valuable in determining which patients are at increased risk of disease recurrence following radical cystectomy and, therefore, who should receive adjuvant chemotherapy.

The value of nuclear area as a prognostic factor in T1 papillary transitional cell carcinoma of the bladder

In a series of 131 T1 papillary transitional cell carcinomas of the bladder, the nuclear areas of 100 nuclei (50 from the external papillary zone and 50 from the internal papillary zone) were measured. An attempt was made to correlate retrospectively the value of the mean nuclear area with histological grade and with survival. A higher value was obtained for the mean nuclear area of the internal papillary zone than for that of the external papillary zone. A better survival rate was found after 10 years' follow-up for those tumours whose mean nuclear area in the internal papillary zone was < or = 28 microns2, which suggests that it is in this zone that the nuclear area should be measured. A correlation was observed between the increase in the mean nuclear area value and higher histological grade.

Nuclear grading of renal cell carcinomas--is morphometry necessary?

Comparative investigations of subjective with objective nuclear grading methods of renal cell carcinomas are almost completely lacking. Therefore, we graded 94 cases of this carcinomas by a simple, subjective microscopical estimation as well as by a morphogenetic measurement of nuclear area. Both procedures proved prognostically useful, but the best results were achieved by morphometry. By this method three prognostic groups of renal cell carcinoma were found, provided that the borderlines were drawn at 28 microns 2 and 60 microns 2, respectively. Particularly favourable and unfavourable cases could be separated from average ones, if the means and standard deviations of both the nuclear areas and the diameters were evaluated. Overall, morphometric nuclear analyses are highly desirable, if, for example, morphological data are to be used in the context of prognostic or therapeutic studies on renal cell carcinoma. However, there is a broad distribution of the values for individual cases so that, tumour-biologically, no exact demarcation of prognostically different groups can be expected.