Overstaging of transitional cell carcinoma: clinical significance of lamina propria fat within the urinary bladder

Incidence and Pitfalls of Adipose Tissue Encountered in Urinary Bladder Biopsy/Transurethral Resection Specimens

Despite the College of American Pathologists' recommendation against diagnosing "fat invasion" in urinary bladder biopsies and transurethral resection of bladder tumor specimens (TURBT), some pathologists still consider this scenario as pathologic stage T3. However, a formal evaluation of fat in biopsies/TURBT has not been performed. Material obtained from TURBT is considered as clinical staging (cT) and that obtained from cystectomy is true pathologic staging (pT). Herein, we analyze adipose tissue incidence/distribution, cancer involving fat, staging ramifications, and clinical outcomes in a large series of biopsies/TURBT. Among 366 biopsies/TURBT specimens, data on adipose tissue presence, location, and quantity were analyzed. An initial analysis of 200 consecutive biopsies/TURBT specimens (including benign/cancer), adipose tissue was identified in 37% of 200 specimens (22% biopsies, 78% TURBT), primarily in the lamina propria (57%) or both lamina propria/muscularis propria (32%). A subsequent analysis of 183 invasive cancer (cT1/cT2) biopsies/TURBT revealed adipose tissue in 40% of specimens, predominantly within both the lamina propria and muscularis propria. Among all cT1/cT2 specimens, 26% (23/88) had cancer involving fat. Clinical follow-up on these putative "cT3" specimens revealed 10 patients who underwent radical cystectomy of which only 1 of 10 remained pT3/pT4 (although 8 patients had neoadjuvant chemotherapy). Adipose tissue is commonly found in biopsies/TURBT, predominantly localized in the lamina propria and sometimes extending into the muscularis propria. Importantly, the presence of tumor "invading" fat on biopsies/TURBT does not necessarily indicate pT3 disease. This underscores the need for standardized reporting practices, emphasizing the importance of reserving pathologic staging for cystectomy specimens.

Influence of histologic criteria and confounding factors in staging equivocal cases for microscopic perivesical tissue invasion (pT3a): an interobserver study among genitourinary pathologists

Current oncology guidelines and clinical trials consider giving adjuvant chemotherapy to bladder cancer patients with at least microscopic perivesical tissue invasion (MPVTI) (≥pT3a) on cystectomy. The boundary of muscularis propria (MP) and perivesical tissue is commonly ill defined, and hence, when the tumor involves the interface, interpretation of MPVTI is likely to be subjective. In this study, 20 sets of static images that included 1 nontumoral bladder wall for defining MP-perivesical tissue boundary and 19 bladder cancer cases equivocal for MPVTI with confounding factors were sent to 17 expert genitourinary pathologists for review. The confounding factors were "histoanatomic," as defined by the irregular MP-perivesical tissue boundary, and "tumor related," such as fibrosis, dense inflammation, tumor cells at the edge of the outermost MP muscle bundle, and lymphovascular invasion. These equivocal cases were divided into 3 categories according to the following factors: (1) histoanatomic only (7/19), (2) histoanatomic+tumor related (7/19), and (3) tumor related only (5/19). Participating genitourinary pathologists used different criteria to assess MPVTI: (A) drawing a straight horizontal line using the outermost MP muscle bundle edge as the MP-perivesical tissue boundary reference (3/17); (B) drawing multiple straight lines interconnecting the outermost MP muscle bundle edges (9/17); (C) following the curves of every outermost MP muscle bundle edge (4/17). In category 1 cases, most pathologists who used the A criterion called for absence (6/7), whereas those who used the C criterion called for presence (5/7) of MPVTI, which resulted in disparity in 4/7 cases. There was no circumstance in which criteria A and C agreed on the presence or absence of MPVTI but was opposed by the B criterion in category 1 cases. Median pairwise agreement among all pathologists (regardless of criteria) for all cases (regardless of category) was only "fair" (κ=0.281). However, when only the B criterion was assessed for category 1 cases, median agreement was "substantial" (κ=0.696), and pairwise rater comparisons included 6/36 (17%) "near perfect," 13/36 (36%) "substantial," and 11/36 (31%) "moderate" agreements. When all cases with histoanatomic factors (categories 1 and 2) were combined, median pairwise agreements were: (A) κ=0.588, (B) κ=0.423, and (C) κ=0.512, and the B criterion rater comparisons included 0/36 (0%) "near perfect," 6/36 (17%) "substantial," and 16/36 (44%) "moderate" agreements, which showed the confounding effect of tumor-related factors. For category 3 cases, median pairwise agreement for all pathologists was "fair" (κ=0.286), with consensus agreement in only 2/5 of these equivocal cases. Lymphovascular invasion only at the MP-perivesical tissue boundary was not staged as MPVTI by 87.5% of pathologists. In conclusion, this study showed that interpretation of equivocal cases for MPVTI can be made difficult by factors intrinsic to bladder histoanatomy, defined by an irregular MP-perivesical tissue boundary, and factors related to tumor spread. There are at least 3 different approaches to demarcating an irregular outer MP boundary, and agreement is improved on equivocal cases when a common histoanatomic criterion is used. However, inconsistent agreement of anatomic criteria may cause systematic discrepancy in assessing MPVTI. Tumor-related factors such as dense fibrosis or desmoplasia, obscuring inflammation, tumor cells at the edge of the outermost MP muscle bundle, and admixed lymphovascular invasion can also negatively influence the agreement on interpretation of MPVTI. This study highlights the need to adopt common criteria in defining the outer MP boundary. Future studies may identify the most clinically relevant histoanatomic criteria for MPVTI.

Hydronephrosis as a prognostic marker in bladder cancer in a cystectomy-only series

OBJECTIVES

Hydronephrosis in patients with bladder cancer is caused by tumour at the ureteral orifice, secondary ureteral tumours, intramural or extravesical tumour infiltration, or compression of the ureter. This study investigated the prognostic impact of hydronephrosis in bladder cancer.

METHODS

A series of 788 patients were treated with radical cystectomy with curative intent for transitional cell carcinoma of the bladder without neoadjuvant/adjuvant radiotherapy/chemotherapy between January 1986 and September 2003. All patients had a complete follow-up until death or until the study's end date. Survival rates were calculated using the Kaplan-Meier method. A multivariate analysis with a Cox regression model was performed with respect to potential influencing factors.

RESULTS

A total of 108 patients (13.7%) had unilateral and 25 patients (3.2%) had bilateral hydronephrosis. The rate of organ-confined tumours was significantly higher in patients without hydronephrosis (67.9% vs. 37.6%; p<0.001). Forty-three (32.3%) of the 133 hydronephrotic patients had a tumour involving the ureteral orifice. In this group the rate of organ-confined tumours was significantly higher than in the other patients with hydronephrosis (53.5% vs. 30.0%; p=0.009). In the multivariate analysis, preoperative hydronephrosis was determined as an independent prognostic marker for recurrence-free survival besides the pT classification and lymph node status (p=0.0015). The etiology of hydronephrosis did not affect the tumour-specific survival.

CONCLUSIONS

Hydronephrosis at the time of diagnosis of bladder cancer is associated with a high probability of advanced tumours. It is an independent prognostic factor for recurrence-free survival.

Intravesical adipose tissue: a quantitative study of its presence and location with implications for therapy and prognosis

Accurate pathologic staging of carcinomas of the urinary bladder involves assessment of invasion by the tumor into the bladder wall and beyond into perivesical soft tissue. The presence of tumor within perivesical soft tissue implies pathologic stage pT3 (AJCC/UICC system, 1997). In traditional textbooks of histology, anatomy, pathology, and in the literature, other than a single case report and a brief reference in another paper, there is no information on the presence of adipose tissue in the lamina propria or muscularis propria of the urinary bladder. Nine hundred forty-three sections from 139 cystectomy specimens were evaluated for the presence, location, and quantity of adipose tissue within the lamina propria and muscularis propria. The histology of the perivesical soft tissues and the nature of its delineation from muscularis propria were also analyzed. Adipose tissue was seen within the lamina propria in 53% (74 of 139) of cystectomies and in 17.6% (166 of 943) of the examined sections. It was located predominantly in the deep lamina propria (at or below the muscularis mucosae) in 81.1% (60 of 74) of the cystectomies and in 91% (151 of 166) of the sections. Within the lamina propria it was predominantly seen as small localized aggregates in 92% (153 of 166) of sections. All cases showed adipose tissue within the muscularis propria. Adipose tissue was identified within the superficial (inner) muscularis propria in 54% (512 of 943) of sections and was predominantly in small aggregates in 80.5% (412 of 512) of sections. It was in moderate to abundant quantities within the deep (outer) muscularis propria in 60.7% (572 of 943) of sections. The perivesical soft tissue was almost exclusively composed of adipose tissue with variable vascularity. Delineation of the perivesical adipose tissue from the deep (outer) muscularis propria was typically indistinct because muscle bundles of the latter haphazardly merged with the perivesical adipose tissue. Based on these findings, we conclude that adipose tissue is frequently present in the lamina propria and muscularis propria of the urinary bladder wall, and is usually scant in the former location and frequently abundant in the latter. Awareness of the high frequency of adipose tissue within the urinary bladder wall has prognostic and therapeutic implications. In transurethral resection of bladder tumor (TURBT) specimens, misinterpretation of tumor infiltrating adipose tissue within lamina propria (pT1) as perivesical soft tissue involvement (pT3) may potentially result in unwarranted aggressive management. Substaging of muscle invasive tumors should be performed in cystectomy specimens only, because the junction of muscularis propria and the perivesical adipose tissue is typically ill-defined. Muscularis propria adipose tissue in TURBT specimens may be erroneously assumed to be perivesical adipose tissue, potentially leading to overstaging of the primary tumor.

Predicting extravesical extension of bladder carcinoma: a novel method based on micrometer measurement of the depth of invasion in transurethral resection specimens

OBJECTIVES

Patients with bladder cancer and extravesical extension (Stage T3 or greater) have worse survival than those with organ-confined cancer. We sought to determine whether the depth of invasion in transurethral resection of the bladder (TURB) specimens will predict extravesical extension in patients treated by radical cystectomy.

METHODS

We studied 90 patients diagnosed with invasive bladder carcinoma between 1979 and 1984. The 1997 TNM (tumor, lymph node, metastasis) system was used for pathologic staging. The mean patient age was 65 years (range 44 to 78). The male/female ratio was 5:1. All patients had invasive bladder cancer at TURB. Muscle invasion was identified in 35 patients (39%) and lamina propria invasion was present in 55 patients (61%) in the TURB specimens. The depth of invasion in the TURB specimens was measured by an ocular micrometer. All patients were treated by radical cystectomy. The median interval from TURB to cystectomy was 44 days (range 2 to 159). Extravesical extension (Stage T3 or greater) at cystectomy was present in 39 patients (43%).

RESULTS

The depth of invasion was associated with final pathologic stage (Spearman correlation r = 0. 58, P <0.001). The overall accuracy of the depth of invasion for the prediction of extravesical extension, measured by the area under the receiver operating characteristic curve, was 0.81 (standard error 0. 045). The mean depth of invasion among patients with extravesical extension at cystectomy was 4.0 mm compared with 2.2 mm for those without extravesical extension. On the basis of a 4.0-mm cutoff point, the sensitivity, specificity, positive predictive value, and negative predictive value for extravesical extension were 54%, 90%, 81%, and 72%, respectively.

CONCLUSIONS

Patients with a bladder cancer depth of invasion greater than 4 mm in the TURB specimens, as measured by micrometer, are likely to have extravesical extension, and more aggressive treatment should be considered.

Predicting cancer progression in patients with stage T1 bladder carcinoma

PURPOSE

A significant number of patients with stage T1 bladder carcinoma are at risk for cancer progression. We sought to identify factors associated with cancer progression in a series of patients with stage T1 bladder carcinoma treated with a contemporary therapeutic approach.

PATIENTS AND METHODS

The study population consisted of 83 consecutive patients in whom stage T1 bladder carcinoma was diagnosed at the Mayo Clinic between 1987 and 1992. All patients underwent transurethral resection of the bladder (TURB) and had histologic confirmation of the diagnosis. The mean age was 71 years (range, 47 to 94 years). The male-to-female ratio was 3.9:1. The mean length of follow-up was 5.2 years (range, 1 day to 10.4 years). The depth of lamina propria invasion in the TURB specimens was measured with an ocular micrometer. Cancer progression was defined as the development of muscle-invasive or more advanced stage carcinoma, distant metastasis, or death from bladder cancer.

RESULTS

The overall 5- and 7-year progression-free survival rates were 82% and 80%, respectively. The depth of invasion in the TURB specimens was associated with cancer progression (hazards ratio, 1.6 for doubling of depth of invasion; 95% confidence interval, 1.03 to 2.4; P =.037). The 5-year progression-free survival rate for patients with depth of invasion of >/= 1.5 mm was 67%, compared with 93% for those with depth of invasion of less than 1.5 mm (P =.009). No other variable, including age, sex, tobacco use, alcohol use, the presence of carcinoma-in-situ, histologic grade, lymphocytic infiltration, or muscularis mucosae invasion, was associated with cancer progression.

CONCLUSION

The depth of invasion in the TURB specimens, measured with a micrometer, is predictive of cancer progression in patients with stage T1 bladder carcinoma.

Substaging of T1 bladder carcinoma based on the depth of invasion as measured by micrometer: A new proposal

BACKGROUND

A significant number of T1 bladder carcinoma patients are understaged by transurethral resection of the bladder (TURB), indicating a substantial need for more accurate staging.

METHODS

The authors studied 55 patients with T1 bladder carcinoma detected by TURB at the Mayo Clinic between December 1979 and July 1984. The mean age of the patients was 66 years (range, 50-78 years). All patients were treated by cystectomy. The median interval from TURB to cystectomy was 10 days. Grading was performed according to the 1998 World Health Organization/International Society of Urologic Pathology grading system. The 1997 TNM classification was used for pathologic staging. In addition, the depth of invasion was measured from the mucosal basement membrane by micrometer. Receiver operating characteristic (ROC) analysis was used to evaluate the usefulness of depth of invasion as a marker for advanced stage bladder carcinoma (>/= T2).

RESULTS

The final pathologic stages were Ta (2 patients), T1 (10 patients), T2a (9 patients), T2b (13 patients), T3 (11 patients), and T4 (10 patients) at cystectomy. There was a significant correlation between the depth of invasion at TURB and the final pathologic stage (Spearman correlation coefficient = 0.63; P < 0.001). The overall accuracy for the prediction of advanced stage (>/= T2) bladder carcinoma as measured by the area under the ROC curve was 0.89 (standard error, 0.05). Using 1.5 mm as a threshold (with >1.5 mm indicating advanced stage disease), the sensitivity, specificity, and positive and negative predictive values were 81%, 83%, 95%, and 56%, respectively. Histologic grade at the time of TURB also was associated significantly with final pathologic stage at cystectomy (P = 0.03) whereas stratification of patients according to invasion above or below the muscularis mucosae at TURB was not a significant predictor of final pathologic stage.

CONCLUSIONS

The results of the current study show that substaging of T1 bladder carcinoma according to the depth of invasion (as measured by micrometer) provides significant prognostic information. Therefore the authors recommend that it be reported in specimens obtained by TURB.