Flow and image cytometry for DNA analysis in bladder washings: improved concordance by using internal reference for flow

Diagnostic performance of the urinary bladder carcinoma antigen ELISA test and multiparametric DNA/cytokeratin flow cytometry in urine voided samples from patients with bladder carcinoma

BACKGROUND

The objective of the current study was to comparatively analyze the sensitivity and specificity of flow cytometric DNA/cytokeratin 8/18 measurements and the urinary bladder carcinoma antigen (UBC) enzyme linked immunoabsorbent assay (ELISA) test for the detection of bladder carcinoma in voided urine samples.

METHODS

Eighty-one fresh urine voided samples, preserved frozen for a maximum period of 3 months, belonging to patients with an active bladder carcinoma (n = 37), patients who were free of disease as confirmed by cystoscopy (n = 19), patients receiving intravesical therapy (n = 17), and individuals with other benign and malignant conditions (n = 8), were collected. Flow cytometry measurements of thawed samples were based on the detection of cytokeratin (CK) 8+ and CK18+ cells using the 3F3 and 6D7 monoclonal antibodies alone or in combination with the measurement of cell DNA contents, after propidium iodide staining. Urinary bladder carcinoma antigen test was measured by ELISA.

RESULTS

Patients were grouped according to the presence (n = 44) or absence (n = 29) of bladder carcinoma as confirmed by cystoscopy, and taking cutoffs of 9.7 microg/L for UBC-ELISA, 75% for the percentage of 3F3 (+) and 6D7 (+) cells, and 10.6% for the proportion of hyperdiplod cells that suggested a specificity of 83%, the individual sensitivity obtained for each parameter was 77%, 5%, 9%, and 77%, respectively. The presence of DNA aneuploid populations showed a relatively low sensitivity (36%) although it was the most specific parameter (93%). Combining UBC antigen test with the proportion of cells showing DNA content higher than 2n increased to 89% the sensitivity of the UBC antigen alone. However, false-positive results for both techniques were found in individuals with urologic diseases other than bladder carcinoma and in patients receiving intravesical therapy.

CONCLUSIONS

The authors' results suggest that the combined use of the UBC antigen test and DNA/cytokeratin flow cytometry double stainings for the analysis of freshly obtained urine voided samples, cryopreserved to assure cellular integrity, is of great clinical utility for the detection of tumor recurrence in patients with bladder carcinoma.

Assessment of DNA flow cytometry as a surrogate end point biomarker in a bladder cancer chemoprevention trial

Although conventional cytology represents the most widely performed cytometric analysis of bladder cancer cells, DNA flow cytometry has, over the past decade, been increasingly used to evaluate cell proliferation and DNA ploidy in cells from bladder washings. We have investigated whether DNA flow cytometry and conventional cytology of epithelial cells obtained from bladder washings provide reliable surrogate endpoint biomarkers in clinical chemoprevention trials. We used cytometric and clinical data from a chemoprevention trial of the synthetic retinoid Fenretinide on 99 patients with superficial bladder cancer. A total of 642 bladder washing specimens obtained from the patients at 4 month intervals was analyzed. Intra-individual agreement and correlation of flow cytometric DNA ploidy (diploid vs. aneuploid), DNA Index, Hyper-Diploid-Fraction (proportion of cells with DNA content higher than 2C), and conventional cytologic examination, as assessed by kappa statistics and Spearman's correlation test, were poor from baseline through 24 months. Moreover, no correlation was found between DNA ploidy and cytology at each time point. The same results were obtained when the analyses were stratified by treatment group. In addition, the association between the results of bladder washing (by either DNA flow cytometry or cytology) and concomitant tumor recurrence was significant only for abnormal cytology, while neither biomarker was predictive of tumor recurrence at the subsequent visit. During the time of this study only four patients progressed to muscle-invasive bladder cancer, indicating the "low-risk" features of the patient population. We conclude that DNA flow cytometry and conventional cytology on epithelial cells obtained from bladder washings do not appear to provide suitable surrogate endpoint biomarkers during the early stages of bladder carcinogenesis.

Image analysis combined with visual cytology in the early detection of recurrent bladder carcinoma

BACKGROUND

Early detection of recurrent transitional cell carcinoma of the bladder (TCC) is important to permit early treatment, which produces maximal preservation of the bladder and maximum survival.

METHODS

This retrospective cohort study attempted to determine the period of time over which urinary DNA image analysis combined with visual cytology is useful in the early detection of recurrent TCC of the bladder. The authors believe this study is unique in that it measured the effectiveness of this test (image analysis plus visual cytology combined) at varying times before clinical diagnosis of recurrence was made. The cohort was comprised of 175 urologic patients from urologic practices across the U.S. Data, collected between January 1991 and February 1994, included cystoscopy, biopsy, DNA image analysis, and visual cytologic reports.

RESULTS

Sixty patients in the cohort were found to have active TCC whereas 115 patients had a history of, but no active, disease during the follow-up period. As expected, the sensitivity and specificity of DNA image analysis in combination with visual cytology, and DNA image analysis alone, were greatest when urinary samples were obtained close to the time of diagnosis. In general, the longer the interval from the combined tests to the time of diagnosis, the lower the sensitivity. The combined tests had predictive value up to 3 months prior to clinical diagnosis when any detectable cytologic abnormality was considered positive. At the optimal cutoff points as determined from receiver operating characteristic curves, sensitivity increased when DNA image analysis was supplemented with visual cytology.

CONCLUSIONS

The combination of DNA image analysis and visual cytology provides a better method for the early detection of recurrent TCC than DNA image analysis alone. This test potentially may be useful in providing information regarding bladder tumor recurrence up to 3 months prior to clinical evidence of disease.

Deoxyribonucleic acid ploidy enhances the cytological prediction of recurrent transitional cell carcinoma of the bladder

PURPOSE

We determined whether deoxyribonucleic acid (DNA) ploidy analysis by image analysis cytometry enhances the cytological diagnosis of recurrent transitional cell carcinoma of the bladder.

MATERIALS AND METHODS

A retrospective study was performed during a 5-year period to evaluate the cytological diagnosis and DNA ploidy analysis of 469 patients with previously diagnosed superficial transitional cell carcinoma. Cytological and DNA ploidy analysis was performed on 1,034 urine and bladder wash specimens, and the patients were monitored with cystoscopy and biopsies as clinically indicated. Cytology results were classified as normal, atypical, dysplastic or cancerous, and DNA ploidy was defined as normal if the diploid index was 1.2 or less, the S phase+G2M fraction was less than 21% or if there were 3% or less hyperploid cells, or abnormal if there was an increased S phase+G2M fraction, an aneuploid peak on the histogram or tetraploidy or hyperploidy was present.

RESULTS

The majority of patients (85 of 88, 97%) with a cytological diagnosis of cancer had an abnormal DNA ploidy, and in 60 of 85 of these patients (71%) recurrence was diagnosed within 6 months. Only 5 of 284 specimens (2%) with normal cytology had abnormal DNA ploidy and 1 of these 5 (20%) heralded transitional cell carcinoma recurrence. However, in 145 patients with atypical cytological findings 29 (20%) with abnormal DNA ploidy had a recurrence, compared to 20 of 391 (5%) with normal DNA ploidy (p < 0.0001). Similarly, in 101 patients with dysplastic cytological findings 39 (39%) with abnormal DNA ploidy had transitional cell carcinoma recurrence compared to 4 of 25 with normal ploidy (p = 0.033).

CONCLUSIONS

Abnormal DNA ploidy determined by image analysis significantly enhances the detection of bladder tumor recurrence in patients with atypical or dysplastic cytology but not in those with normal cytology or frank carcinoma on cytological findings.

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.