Types Of Bladder Cancer
There are several different types of bladder cancer and treatment will depend on the type, grade and stage of the cancer.
Transitional cell bladder cancer
When people in the UK talk about bladder cancer they are usually referring to transitional cell bladder cancer (also known as urothelial carcinoma or sometimes TCC). This type of bladder cancer develops from the cells of the bladder lining (urothelium) - these are called transitional cells. This is by far the most common form of bladder cancer in the UK accounting for more than 90% of all new bladder cancers diagnosed.
The information on treatment options and prognosis of bladder cancer elsewhere on this website, and indeed in most books or other sources, refers to treatment and prognosis of transitional cell cancer of the bladder. There is information about some of the rarer types of bladder cancer further down this page.
Transitional cell bladder cancers are not all the same.
Non-Muscle Invasive Bladder Cancer (NMIBC) sometimes referred to as superficial bladder cancer
This is where the cancer is smaller and confined to the bladder lining layers and has not spread into the muscle wall of the bladder. About 75-80% of patients newly diagnosed with bladder cancer have non-muscle invasive tumours.
These early stage bladder cancers are divided into 3 risk groups - low risk, intermediate (medium) risk and high risk - which indicate how likely it is that the cancer might spread further (known as progression) or come back after treatment (known as recurrence). The risk group depends on several things including the stage, grade and type of bladder cancer. As the name implies, High Risk NMIBC is a serious version of bladder cancer and can become life threatening if not treated successfully. It certainly isn't just a cancer that is 'superficial' or trivial in any way.
Muscle-Invasive Bladder Cancer (MIBC)
Muscle Invasive bladder cancer tumours are larger, aggressive and ,again as the name implies, have already invaded into the muscle of the bladder or beyond. The diagnosis of muscle-invasive bladder cancer is likely to be based upon the microscopic examination of the bladder wall specimens that have been resected from your bladder (the histology) at the time of your TURBT.
The grading and staging section tells you how bladder cancer tumours are assessed.
Muscle Invasive bladder cancers are always high risk and are a serious version of cancer; they require radical treatment. There is more information on both non-muscle invasive and muscle-invasive bladder cancer in the Diagnosis and the Treatments section.
Other variants of bladder cancer types
Sometimes other cancer types and variants may develop within the bladder. These different variants and forms of bladder cancer, mostly rare, are briefly outlined below with specific reference to their implications for prognosis and treatment.
Variants of transitional cell / urothelial bladder cancer
1 Squamous differentiation
Squamous differentiation is the most common variant of urothelial cancer. It is present to some degree in about 20% of all transitional cell cancers. The presence of squamous differentiation within a urothelial cancer may indicate:
- a worse prognosis
- higher risk of recurrence
- poorer response to chemotherapy and radiotherapy
2 Glandular differentiation
Glandular differentiation is a variant of urothelial cancer occurring in about 10% of cases. Due to minimal research and literature on this variant, the issue of outcomes has not been clarified and these tumours tend to be treated along the same lines as other urothelial cancers.
3 Nested variant
This is an aggressive variant of urothelial cancer. It is rare but the literature available does suggest a poorer outcome compared to simple urothelial cancer.
4 Micropapillary carcinoma
This variant of urothelial cancer has an incidence of about 5%. It tends to respond poorly to intravesical therapy. If this variant is present within a urothelial cancer a urologist may recommend primary cystectomy as the most appropriate treatment option.
5 Lymphepithelioma-like carcinoma
This variant is rare but generally carries a favourable prognosis if lymphepithelioma-like carcinoma forms the predominant pattern. Intravesical chemotherapy seems to produce high response rates.
Plasmacytoid urothelial carcinoma is a very rare and tends to displays aggressive behaviour.
7 Sarcomatoid carcinoma
This variant of urothelial carcinoma has only been described in small case series and carries a poor outcome for patients. Where possible radical cystectomy is the preferred treatment option for T1 urothelial cancer with sarcomatoid change.
Non-transitional cell bladder cancer
These cancer types include:
- squamous carcinoma
- small cell carcinoma
- malignant melanoma
It is important to distinguish these cancers from transitional cell carcinoma, since their treatment and prognosis are different.
1 Squamous Cell Carcinoma (SCC)
Squamous cell cancer affects the flat, scale-like cells on the surface of the skin called squamous cells. It has historically been associated with the parasite schistosoma hematoebium in parts of the world where schistosomiasis is common (eg Egypt). This is rarely the underlying cause in the UK where it accounts for about 3% of all newly diagnosed bladder cancers. The common causes in the UK include long term indwelling catheters and chronic urinary infections.
SCC, stage for stage, is a more aggressive disease than urothelial cancer and usually presents at quite an advanced stage. There is no role for intravesical therapy, or for neoadjuvant systemic chemotherapy and the tumour responds poorly to radiotherapy making primary radical surgery (cystectomy) the main treatment option if appropriate.
Adenocarcinoma constitutes 2% of all bladder cancers. There are 3 type of adenocarcinoma that affect the bladder:
- primary bladder adenocarcinoma
- adenocarcinoma arising from the urachus (an embrologic remnant that drains the foetal bladder before closing)
- metastatic adenocarcinoma. The most common primary sites for metastatic adenocarcinomas come from prostate, ovary and colon cancer.
Adenocarcinoma is often more aggressive than urothelial cancer and often advanced at presentation. There is no role for intravesical agents. As this is a rare tumour, there is currently no data as to how adjuvant therapy may alter the disease course.
Research suggests that radiotherapy is not very effective against adenocarcinomas, and radical cystectomy is the treatment of choice. The prognosis after radical surgery is often favorable for primary adenocarcinoma of the bladder and unlike in urothelial cancer a partial cystectomy may be a treatment option in selected cases
3 Small-cell carcinoma
Small cell carcinoma is more commonly a malignancy of the lungs, but may affect the bladder accounting for about 1% of primary bladder cancers in UK.
Small cell cancer of the bladder behaves aggressively but may respond well to multimodal therapy with systemic chemotherapy and radiotherapy which remains the treatment of choice in most units. Radical surgery to remove the bladder may be offered in selected cases.
Sarcomas of the bladder are rare and tend to be aggressive.
- Rhabdomyosarcoma is the most common tumour of the lower genitourinary tract in children (mean appearance at five years of age), and rarely, is found in adults The treatment involves multimodal therapy, including chemotherapy, radiotherapy and organ sparing surgery with bladder preservation.
- Carcinosarcoma is rare and usually not diagnosed until tumour growth is already far advanced. Radical cystectomy is the treatment of choice.
- Leiomyosarcomais a malignancy of smooth muscle origin and is extremely rare in the bladder (less than 0.5% of cases). Historically, patient survival has been poor. Because the efficacy of chemotherapy and radiotherapy remains unclear, the treatment of choice is by radical cystectomy or partial cystectomy when tumour location and size permit.
Lymphoma is a systemic disease of the blood lymphoid cells. Whilst it may affect the bladder it is invariably a systemic disease and as such is managed by chemotherapy through the haematologists.
6 Malignant Melanoma
This is a skin cancer that very occasionally affects the bladder.
Tumours of this type are extremely rare (0.06% of primary bladder cancer) in the bladder. Bladder pheochromocytomas as for elsewhere in the body may be hormonally active with elevated catecholamines and metabolites.