Cytology and cystoscopy
These two diagnostic approaches are considered the gold standard in the diagnosis of bladder cancer .
Cytology is the examination of a urine sample under a microscope, which is performed in a laboratory to detect the presence of cancer or pre-cancer cells.
During a cystoscopy, a thin tube with a camera is inserted through the urethra (the duct that that lets urine out of the bladder during urination) into the bladder. This procedure, performed at an outpatient clinic in the hospital or in the urologist’s office, enables the urologist to examine the inner layer of the bladder. Cytology is invasive and usually associated with discomfort or pain during or after the procedure.
When an abnormality is observed, a transurethral resection of bladder tumor (TURBT) is performed under general anesthesia in the operation room. The abnormal-looking tissue is removed and sent for microscopic investigation for the presence of cancerous cells.
Imaging studies of the urinary tract are useful to investigate whether the cancer has spread outside the bladder into nearby tissues or lymph nodes. However, tumors in the bladder itself may be missed by imaging, so, bladder cystoscopy is always required for a proper diagnosis.
- CT urogram is a radiological exam in which a contrast dye is injected into the veins to outline the urinary tract. Multiple X-ray images are taken and sent to a computer to reconstruct detailed 2D images. This imaging technique can also identify kidney stones and swelling of the kidney due to downstream blockage.
- MR urogram uses a magnetic field and radio waves to produce detailed pictures. This technology does not use radiation or contrast dyes and it is useful to detect disease spread.
- Renal ultrasound applies sound waves for the shaping, sizing and localization of the kidneys. Although it is safe because it does not use radiation or a contrast dye, small kidney stones and tumors may be missed.
Grading and staging a bladder cancer tumor
Grade (ranging from 1 to 3): describes what the cancer cells look like and how many cells are multiplying. Grading is important to predict how fast the cancer will grow and spread. The higher the grade, the more the cells differ from normal bladder cells and the faster they spread.
Stage (ranging from 0 to 4): the extent to which the disease has progressed. Staging is used to plan the best treatment strategy for the cancer. The higher the stage the more the disease has grown into the layers of the bladder.
Three different parameters are often used in the staging system of bladder cancer: T, N and M:
- T categories describe how deep the tumor has grown into the bladder wall and if the tumor has invaded nearby tissues
- N categories describe whether the tumor has spread to lymph nodes
- M categories describe whether the tumor has spread to distant organs
The T categories define the bladder tumor itself:
- Ta: a papillary tumor with a long, thin finger-like structure growing in the inner urothelium layer
- CIS (carcinoma in situ), TIS: a superficial flat tumor on the inner layer
- T1: a tumor invaded in the connective tissue lining, but not into the muscle
- T2: a tumor invaded the muscle layer of the bladder wall
- T3: a tumor penetrated through the bladder wall and invaded the fat layer surrounding the bladder
- T4: a tumor invaded other nearby organs such as the uterus, prostate, vagina or pelvic wall
Ta, CIS and T1 are NMIBC and account for approximately 70-80% of all newly diagnosed bladder cancers, and T2, T3 and T4 are muscle invasive and more difficult to treat.