Urologic Oncology: Seminars and Original Investigations
Original articleClinical — bladderImpact of micropapillary urothelial carcinoma variant histology on survival after radical cystectomy1
Introduction
Bladder cancer is a major public health problem in the USA [1]. In 2011, an estimated 69,250 Americans will be diagnosed with bladder cancer and 14,990 Americans will die of bladder cancer [1]. Bladder cancer can be categorized based on histologic type as pure urothelial carcinoma (UC), urothelial carcinoma with aberrant differentiation, and pure nonurothelial carcinoma [2]. The most common aberrant differentiation patterns are squamous and/or glandular, small-cell carcinoma, sarcomatoid, and micropapillary carcinoma [2], [3], [4]. Pure forms of nonurothelial carcinomas include squamous cell carcinoma, adenocarcinoma, and small-cell carcinoma [2], [3], [4].
Micropapillary urothelial carcinoma (MUC) is a rare histologic variant that closely resembles papillary serous carcinoma of the ovary [5]. It is estimated to account for approximately 0.7%–2.2% of all urothelial tumors and less than 200 cases of bladder MUC have been reported in the medical literature [6], [7], [8], [9], [10], [11], [12]. Current evidence from case series suggests that MUC is an aggressive histologic variant associated with poorer prognosis [10], [12]. However, the role of MUC variant histology as an independent prognostic factor for survival outcomes after radical cystectomy has not been studied [13]. Here we examined the impact of MUC on survival after radical cystectomy. We hypothesized that MUC would be independently associated with poorer prognosis.
Section snippets
Study cohort
Fig. 1 presents the study cohort selection process. We identified 1,681 patients who underwent open radical cystectomy and extended pelvic lymph node dissection for primary urothelial carcinoma of the urinary bladder at the University of Southern California (USC) in a prospectively maintained Institutional Review Board-approved database. Three hundred one patients were excluded, and the final study cohort included 1,347 patients with pure UC and 33 patients with MUC treated between January 1,
Results
A total of 1,347 patients with pure UC and 33 patients with MUC were included in the current analyses; 27 out of 33 patients (82%) with MUC had an incidental diagnosis based on pathologic analysis of the radical cystectomy specimen. The median follow-up duration for the overall cohort was 10 years (range, 0–25 years). The median follow-up duration for patients with UC and MUC was 10 and 4 years, respectively (P = 0.28).
Discussion
Numerous variants of UC of the urinary bladder have been described [13]. Micropapillary urothelial carcinoma is a rare histologic variant of UC with an aggressive biological phenotype [16], [17]. Although the prognostic implications of tumors with MUC variant histology are poorly defined, current thinking is that this type of aberrant differentiation portends poorer prognosis [13]. In this study from the University of Southern California, we evaluated the impact of MUC variant histology on
Conclusions
In summary, outcomes of radical cystectomy for patients with MUC are similar to those with UC when controlling for other clinical and pathologic factors. Further prospective, multi-institutional evaluation of MUC variant histology is needed.
References (18)
- et al.
Micropapillary bladder carcinoma: A clinicopathologic study of 20 cases
J Urol
(1999) - et al.
Micropapillary carcinoma of the urothelial tract: A clinicopathologic study of 38 cases
Ann Diagn Pathol
(2005) - et al.
The impact of variant histology on the outcome of bladder cancer treated with curative intent
Urol Oncol
(2009) - et al.
Lymph node dissection technique is more important than lymph node count in identifying nodal metastases in radical cystectomy patients: A comparative mapping study
Eur Urol
(2011) - et al.
Neoadjuvant systemic therapy or early cystectomy?Single-center analysis of outcomes after therapy for patients with clinically localized micropapillary urothelial carcinoma of the bladder
Urology
(2011) - et al.
Cancer statistics
CA Cancer J Clin
(2011) - et al.
Pathology and genetic of tumours of the urinary system and male genital organs
(2004) - et al.
The World Health Organization/international society of Urological pathology consensus classification of urothelial (transitional cell) neoplasms of the urinary bladderBladder Consensus Conference committee
Am J Surg Pathol
(1998)
Cited by (52)
Clinicopathologic Analysis of Micropapillary Urothelial Carcinoma of the Upper Urinary Tract: Implications for HER2-Targeted Therapy
2023, Clinical Genitourinary CancerUrothelial Carcinoma: Divergent Differentiation and Morphologic Subtypes
2022, Surgical Pathology ClinicsWhat Is the Significance of Variant Histology in Urothelial Carcinoma?
2020, European Urology FocusThe impact of variant histological differentiation on extranodal extension and survival in node positive bladder cancer treated with radical cystectomy
2019, Surgical OncologyCitation Excerpt :Overall, the impact of variant UCB histology on pathological features and survival metrics remains controversial. While a number of previous reports have found an association of variant UCB histology with adverse pathological features including lymph node status [3,7,18], this association did not indiscriminately translate into inferior survival in adjusted outcome analyses of contemporary series [6,7,19]. Our findings merit several clinical implications.
The authors declare no conflict of interest.
- 1
Presented at the Annual Meeting of the Society of Urologic Oncology, Bethesda, Rockville, MD, November 30–December 2, 2011 and at the Genitourinary Cancer Symposium, San Francisco, CA, 2012, February 2–4, 2012.