Muscle-invasive Bladder Cancer
What is muscle-invasive bladder cancer?
About a quarter of patients diagnosed with bladder cancer have a muscle-invasive form that has grown into the muscular part of the bladder wall (stages T2–T4). This type of cancer has a higher chance of spreading to other parts of the body (metastatic) and needs a different and more radical form of treatment. Muscle-invasive bladder cancer will be fatal if untreated.
Computed tomography (CT scan) is particularly important for further work-up in muscle-invasive bladder cancer. With a whole-body CT scan, done in less than 10 minutes, the physician can tell if the cancer has already grown out of the bladder and into the surrounding fat tissue or adjacent organs and if there are signs of spreading to other organs (metastatic disease). By adding intravenous contrast agent, which is excreted into the urine by the kidneys, the urinary tract above the bladder can be visualized and tumour growth identified.
Prior to treatment, it is essential to evaluate whether the cancer is metastatic. If the CT scan indicates that the cancer has spread to your soft (visceral) organs, your bones or lymph nodes. This will possibly change the treatment decisions.
Additional magnetic resonance imaging (MRI scans) or bone scans may be performed, although this is not routinely done. Bone and brain metastases are rare at the time that muscle-invasive bladder cancer is diagnosed. Therefore, your doctor would only consider a bone scan or additional brain imaging if you have specific symptoms that suggest bone or brain metastases.
Unclear findings might also be probed with a needle biopsy to confirm metastatic disease.
A combination of positron emission tomography (PET scan; uses a radioactive tracer) and CT scan (PET/CT) is increasingly being used in European centres, although it is not generally available in all countries. PET/CT may improve the ability to detect distant metastases. It is not recommended for staging bladder tumours because urinary excretion of the radioactive tracer makes tumour staging very difficult (see Diagnosis and Classification).
FAQ – What is a urothelial carcinoma?
This term refers to cancer that typically occurs in the urinary tract (kidney, bladder, ureters, urethra) and indicates the type of cancer, which affects urothelial cells as opposed to other types of cells in the urinary tract. Most bladder cancers are urothelial carcinoma (also called transitional cell carcinoma).
Prognosis and risk stratification
The long-term prognosis for patients with muscle-invasive bladder cancer is determined by the extent of tumour growth (stage). As opposed to non-muscle-invasive bladder cancer aggressiveness (grade) which is determined by the pathologist is less important, since virtually all invasive tumours are high grade. Staging and grading are described in detail in the Diagnosis chapter.
Terms your doctor may use:
- High grade: Tissue is greatly altered in appearance, indicating aggressive tumour growth.
- Low grade: Tissue is mildly altered in appearance, indicating less aggressive tumour growth.