Challenges in Pathologic Staging of Bladder Cancer: Proposals for Fresh Approaches of Assessing Pathologic Stage in Light of Recent Studies and Observations Pertaining to Bladder Histoanatomic Variances

The paradigm of pathologic stage (pT) categorization in bladder cancer remains the depth of invasion into the different histologic layers of the bladder wall. However, the approaches to assigning pT stage category toward an enhanced outcome stratification have been marked by challenges and innovations, due in part to our growing appreciation of the surprisingly perplexing bladder histoanatomy. Upstaging of pT1 tumors after radical cystectomy is substantial and underscores the potential value of pT1 substaging in transurethral resection (TUR) specimens. The 2017 American Joint Committee on Cancer tumor-node-metastasis system recommends pT1 substaging but recognizes the need to optimize the approach. Over the years, the cut-off for microinvasion has been significantly lowered to 0.5 mm and is now a promising scheme for pT1 (micrometric) substaging. Unlike the micrometric approach, histoanatomic substaging using muscularis mucosae (MM) and vascular plexus as landmarks is less feasible in TUR specimens and inconsistent in stratifying the outcome of pT1 tumors. The lamina propria possesses inherent variations in depth, MM, and vascular plexus dispositions that should be factored in future pT1 substaging proposals. Histoanatomic variations among the bladder regions also occur, and studies suggest that trigone and bladder neck cancers may have more adverse outcomes. The muscularis propria (MP), besides being the essential histologic landmark for assigning pT2 stage category, is also...
Source: Advances in Anatomic Pathology - Category: Pathology Tags: Review Articles Source Type: research