How do you determine if a lesion is at the Carcinoma In Situ (TIS) stage versus stage one or stage two in Urothelial Carcinoma (UTuC)?

From the Guidelines

To determine if a lesion is at the Carcinoma In Situ (TIS) stage versus stage one or stage two in Urothelial Carcinoma (UTuC), pathological examination of tissue samples obtained through transurethral resection of the bladder tumor (TURBT) with a bimanual examination under anesthesia (EUA) is essential, as it allows for the assessment of the depth of invasion and guides treatment recommendations 1.

Key Considerations

• The distinction between Tis, T1, and T2 requires adequate biopsy samples that include the basement membrane and underlying tissues.
• Tis represents flat, high-grade carcinoma confined to the urothelium without invasion through the basement membrane.
• T1 indicates tumor invasion into the subepithelial connective tissue (lamina propria) but not reaching the muscularis layer.
• T2 means the tumor has invaded the muscularis (muscle layer).

Diagnostic Approach

• Office cystoscopy is used to determine if a lesion is present.
• If a lesion is documented, TURBT with EUA is performed to resect the visible tumor and sample muscle within the area of the tumor to assess invasion.
• Additional diagnostic tests, such as CT scans or MRI of the abdomen and pelvis, may be recommended based on the cystoscopic appearance of the tumor.
• Urine cytology and evaluation of the upper tracts with imaging studies (e.g., CT urography) are also important components of the diagnostic workup.

Treatment Implications

• Accurate staging is crucial as depth of invasion correlates strongly with prognosis and guides appropriate treatment selection.
• Tis and T1 lesions may be managed conservatively in select cases, while T2 disease generally requires more aggressive intervention such as radical nephroureterectomy.
• The management of bladder cancer is based on the pathologic findings of the biopsy specimen, with attention to histology, grade, and depth of invasion 1.

From the Research

Determining the Stage of Urothelial Carcinoma

To determine if a lesion is at the Carcinoma In Situ (TIS) stage versus stage one or stage two in Urothelial Carcinoma (UTuC), several factors and diagnostic methods are considered.

• The diagnosis and staging of UTuC can be challenging due to the rarity of the disease and the limited availability of high-level evidence to guide treatment decisions 2.
• Carcinoma in situ (CIS) of the urinary bladder is defined as a flat lesion comprising cytologically malignant cells that may involve either full or partial thickness of the urothelium 3.
• Accurate diagnosis and staging of UTUC are crucial for further management, and various methods are used, including imaging, urine-based, and endoscopic techniques 4.

Diagnostic Methods

• Computed tomography urography (CTU) is considered the gold standard for imaging and is useful in diagnosing and staging UTUC 4, 5.
• Urine cytology, fluorescent in-situ hybridization, and other urine-based tests can be used to aid in diagnosis, but their accuracy may vary 4.
• Endoscopic methods, such as ureterorenoscopy, photodynamic diagnosis, and narrow-band imaging, can facilitate proper visualization of the tumor 4.
• Biopsy techniques, including the "form tackle" biopsy and cold-cup biopsy, can be used to obtain tissue samples for histopathological examination 4.

Staging and Grading

• The staging of UTUC is based on the extent of the tumor, and the grade is determined by the histopathological characteristics of the tumor cells 3, 6.
• Clinicopathological factors, such as the extent of disease, involvement of the prostatic urethra, and response to treatment, remain the main indicators of outcome 3, 6.
• New optical imaging modalities have improved the detection of CIS of the bladder, and bladder preservation using bacillus Calmette-Guérin immunotherapy remains the cornerstone of treatment for CIS 6.