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Less Common Histologies

Published: April 2008

1. Squamous Cell Carcinomas

The most common cause of squamous cell carcinoma worldwide is schistosomal infections (bilharziasis). In Western countries where this infection is rare, squamous cell carcinoma is rare although an increased risk is associated with spinal cord injuries, especially those with indwelling catheters for ≥ 10 years.(24) Pure squamous cell carcinoma must be distinguished from transitional cell carcinoma with squamous differentiation. Most patients are diagnosed with advanced disease and have a poor prognosis.(25) Five-year survival rates are reported as 5% to 35% depending on the stage at diagnosis.

Radical cystectomy provides a survival rate, which to date has not been improved upon by any other treatment.(26) Patients tend to die of local recurrence but pre-operative radiotherapy seems to have little effect.(27)No effective chemotherapy has been found.

2. Adenocarcinoma

Adenocarcinoma of the bladder is classified by its site of origin: primary, urachal or metastatic from local extension of a primary colon, prostate or ovarian cancer. As such, other primary cancers must be ruled out. Various histologic subtypes have been described for primary adenocarcinoma but their impact on prognosis is unknown.(28)

Primary adenocarcinoma of the bladder has a poor prognosis with five-year survival rates reported in various series as 0% to 31%. Radical cystectomy is a reasonable management option as no other treatment option appears as successful to date. Patients with urachal adenocarcinoma should have an en bloc excision of the urachus and umbilicus with partial cystectomy. Radiotherapy is generally ineffective and there is limited experience with chemotherapy. Combination 5-fluorouracil-based chemotherapy as used for gastrointestinal adenocarcinoma has been tried with low response rates.(29)

3. Small Cell Carcinoma

Small cell carcinomas are tumours of neuroendocrine origin that occur most commonly in the lungs. However, small cell carcinoma can occur in many other organs, including the urinary bladder. The best data for management of small cell carcinoma comes from experience with pulmonary small cell carcinomas.

Small cell carcinomas of the bladder usually present at an advanced stage and tend to be aggressive in their course. Two-thirds of patients present with metastatic disease which most commonly occurs in lymph nodes, liver, bones, lungs, and brain. Once a pathologic diagnosis of small cell carcinoma is made, patients should undergo a full metastatic work-up which includes CT scan of the abdomen and pelvis, chest x-ray, bone scan, and neurologic examination.(30) Chemotherapy is the mainstay of treatment. Patients who are well enough are treated with Cisplatin and Etoposide (see GUSCPERT protocol​). Patients with localized disease can be treated with a combination of chemotherapy and radiotherapy (31) or chemotherapy followed by radical surgery.(32) For more frail patients, they can be treated palliatively with radiotherapy for local problems, or systemically with cyclophosphamide, doxorubicin and vincristine (as per LUCAV) or oral etoposide (as per LUPOE).

SOURCE: Less Common Histologies ( )
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