UROLOGICAL SURVEY
Miyamoto H, Brimo F, Schultz L, Ye H, Miller JS, Fajardo DA, Lee TK, Epstein JI, Netto GJ
Department of Pathology, Johns Hopkins University, Baltimore, Maryland, USA
Arch Pathol Lab Med. 2010; 134: 1160-3
CONTEXT: Few large cohort studies have addressed outcome in patients with noninvasive low-grade papillary urothelial carcinoma (LG-UrCa) following implementation of the 2004 World Health Organization/International Society of Urological Pathology (WHO/ISUP) consensus classification.
OBJECTIVE: To evaluate our cohort of LG-UrCa cases classified according to 2004 WHO/ISUP to reassess outcome and interobserver agreement.
Design: Files were searched for all patients diagnosed with LG-UrCa between 1998 and 2008. All sections were reevaluated for accuracy of classification.
RESULTS: A total of 112 cases initially diagnosed as LG-UrCa were identified. Of those, 8 of 55 cases (15%) initially diagnosed by nonurologic pathologists were reclassified as high-grade papillary urothelial carcinoma and were excluded. The mean length of follow-up was 40.1 months (range, 2-113 months). Tumor recurrence was encountered in 56 of 104 patients (53.8%), including 37 (35.6%) with LG-UrCa or lower-grade tumors and 19 (18.3%) with high-grade papillary urothelial carcinoma. Of the 19 patients demonstrating grade progression, 7 (37%) also developed stage progression (invasive carcinoma, n = 5; metastatic carcinoma, n = 2). Seven patients eventually underwent radical cystectomy. None of the 104 patients died of bladder cancer. The mean number of recurrence episodes was 3.11. The mean durations of time to first recurrence and time to grade progression were 13.9 months and 25.1 months, respectively. The mean size of initial tumors was 1.73 cm. There was no significant correlation between tumor size, patient age, sex, or smoking history and the likelihood for recurrence or grade progression. A significantly higher rate of recurrence was seen in patients with multiple tumors at initial diagnosis (P = .04).
CONCLUSIONS: A tendency to underdiagnose high-grade papillary urothelial carcinoma continues to exist. More than half (53.8%) of patients with LG-UrCa developed recurrence, with an 18.3% incidence of grade progression and a 6.7% incidence of stage progression. Patients with multiple initial tumors had significantly higher risk of developing recurrence.
Editorial Comment
This is a large cohort study of outcome of patients with noninvasive low-grade urothelial carcinoma using the World Health Organization/International Society of Urological Pathology (WHO/SIPU) consensus classification. From a total of 104 patients, 53.8% developed recurrence, with an 18.3% incidence of grade progression and a 6.7% incidence of stage progression. Patients with multiple initial tumors had significantly higher risk of developing recurrence.
The World Health Organization/International Society of Urological Pathology (WHO/SIPU) consensus classification was held in Boston in 1998 during the United States and Canadian Academy of Pathology (USCAP) meeting. The results were published in the American Journal of Surgical Pathology (1). The most important recommendations of the meeting were:
1. It was recommended not to use the traditional term “dysplasia”. For the term moderate dysplasia was recommended to use low-grade intra-urothelial neoplasia and for severe dysplasia or flat carcinoma in situ the term high-grade intra-urothelial neoplasia. Cases with slight dysplasia should be reported by the pathologists.
2. The 1, 2 and 3 grading by the World Health Organization was replaced by low-grade or refer to grade 1, and high-grade to refer to grades 2 or 3.
3. “Urothelial papilloma” without qualifiers refers to the exophytic variant of papilloma, defined as a discrete papillary growth with a central fibrovascular core lined by urothelium of normal thickness and cytology. It is a rare benign condition typically occurring as a small, isolated growth commonly, but not exclusively, in younger patients.
4. It was introduced the term “papillary urothelial neoplasm of low malignant potential”. This is a papillary urothelial lesion with an orderly arrangement of cells within papillae with minimal architectural abnormalities and minimal nuclear atypia irrespective of cell thickness. Patients with these tumors are at risk of developing new bladder tumors of a similar histology. However, occasionally these subsequent lesions manifest as urothelial carcinoma, such that follow-up of the patient is warranted. In the standard classification this tumor corresponds to the “papillary urothelial carcinoma, grade 1 (low-grade), pTa”. This new category avoid labeling a patient as having cancer, which has psychosocial and financial (e.g. insurance) implications, but neither is a benign lesion (e.g., papilloma) diagnosed, so the patient might be adequately followed (2).
References
1. Epstein JI, Amin MB, Reuter VR, Mostofi FK: The World Health Organization/International Society of Urological Pathology consensus classification of urothelial (transitional cell) neoplasms of the urinary bladder. Bladder Consensus Conference Committee. Am J Surg Pathol. 1998; 22: 1435-48.
2. Epstein JI, Reuter VE, Amin MB: Biopsy Interpretation of the Bladder, 2nd ed. Philadelphia, Lippincott Williams & Wilkins. 2010.
Dr. Athanase Billis
Full-Professor of Pathology
State University of Campinas, Unicamp
Campinas, São Paulo, Brazil
E-mail: athanase@fcm.unicamp.br
Patology
Publication Dates
-
Publication in this collection
21 Oct 2010 -
Date of issue
Aug 2010
