Urothelial Carcinoma with Uncertain Muscularis Propria Invasion - Expert Commentary

Detecting muscle-invasion is a critical step that dictates treatment recommendations. A definitive assessment of muscularis propria (MP) invasion cannot be made in a small number of transurethral resections of bladder tumor (TURBTs). Understanding the clinical course of these patients is critical for defining the optimal management strategies.

A new paper published by Hassan et al. in the World Journal of Urology examined the pathology results and the survival outcomes in patients diagnosed during the initial TURBT with urothelial carcinoma ambiguous for muscularis propria invasion (AMP). They included 428 invasive urothelial carcinoma patients who were treated with radical cystectomy between 1999 to 2017. Patients diagnosed with small cell carcinoma or received prior chemotherapy were excluded. The investigators divided the cohort according to the degree of the tumor invasion into three groups: invasion lamina propria (INLP), invasion of muscularis propria (INMP) and AMP.

The investigators found that 69% (296) of patients were in the INMP with an average age of 67 years, 24% (102) of patients with an average age of 66 years were in the INLP group and 7% (30) of patients in the AMP group with an average age of 65 years. After assessing the RC results, they found that invasive carcinoma stage (pT2 or higher) was found in 49% (50/102) of INLP compared to 83.33% (25/30) of AMP (P = 0.002) and 86% (255/296) INMP (P ≤ 001). Metastatic carcinoma in the lymph nodes was seen in 18.36% (18/98) of INLP vs. 35.29% (96/272) of INMP (P = 0.003) vs. 24% (6/25) of AMP (P = 0.729). There was no statistical significance between the AMP and the other two groups in lymph node involvement. Survival of AMP patients was similar to INLP, and both were significantly better than INMP.

The investigators concluded that the majority of AMP patients have muscle-invasive disease. Because neoadjuvant chemotherapy is a standard of care for platinum-eligible muscle-invasive bladder cancer, a repeat TURBT is indicated to make a definitive diagnosis and formulate the appropriate treatment plan.

Written by: Bishoy M. Faltas, MD, Director of Bladder Cancer Research, Englander Institute for Precision Medicine, Weill Cornell Medicine

Read the Abstract

1. Hassan O, Murati Amador B, Lombardo KA, Salles D, Cuello F, Marwaha AS, Daniels MJ, Kates M, Bivalacqua TJ, Matoso A. Clinical significance of urothelial carcinoma ambiguous for muscularis propria invasion on initial transurethral resection of bladder tumor. World J Urol. 2019 Apr 27. doi: 10.1007/s00345-019-02782-y.
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