Urine cytology is a very sensitive examination of urine for cellular components of urine – possibly to detect inflammatory cell changes, dysplasia (“cell changes”) or tumor cells.It is very suitable as an extended measure for early cancer detection of the urinary bladder, urinary tract and renal caliceal system. Due to its sensitivity (percentage of patients in whom the disease is detected by the use of the test, i.e. a positive test result occurs), it is possible to diagnose a possible malignant (malignant) disease at a preliminary or early stage and thus significantly increase the chances of cure (see also “Assessment of cytological findings in urine”). The following are the risk factors for the development of urothelial carcinoma* :
- Smoking (threefold increased risk of disease) – because of the aromatic amines contained in tobacco smoke.
- Truck drivers
- Gas station attendants
- Hairdressers
- Painters
- Workers in the rubber, dye or leather industry
- Aromatic amines in drugs – for example, cyclophosphamide-based cytostatics.
- Other chemical substances in workers in the textile, leather or paint industries.
Between exposure to the carcinogenic (cancer-causing) substances and the development of cancer, up to forty years pass, that is, the latency period is very long. Cofactors for the development of urothelial carcinoma* are;
- Weakened immune system
- Immunosuppressants – for example, after organ transplantation.
- Chronic urinary tract infections
* In addition to urothelial carcinomas, there are other types of carcinoma that are also detected by urine cytology.
The procedure
This examination is neither costly for you nor associated with side effects. Only a urine sample (spontaneous urine or flush cytology) is needed from you. Collection requirements: Discard morning urine, then drink approximately 1,000 ml of fluid and collect urine in tubes, then send it in as fresh as possible. Using a special staining method, the sample is examined in the laboratory for various constituents, such as protein or blood cells (e.g. erythrocytes, leukocytes), which can indicate various diseases. In particular, a search is also made for any pathologically altered cells or cancer cells that may be present as part of the early detection of cancer. Due to the low cost, this examination can be repeated at any time and as often as required. Indications (areas of application)
- Patients with risk factors (see above).
- Painless hematuria (blood in the urine)
- Carcinoma of the urinary bladder – suspected diagnosis or follow-up.
- Cancer of the urinary tract
- Renal calyceal carcinoma
Assessment of cytological findings of urine
Progressive malignant changes in urinary sediment cells are easier to detect than minimal tumor changes in well-differentiated urinary bladder tumors. This results in the weakness of detection in well-differentiated urinary bladder tumors. Notice:
- Sensitivity (percentage of diseased patients in whom the disease is detected by use of the test, i.e., a positive test result occurs) is poor in low-grade NMIBC (non-muscle-invasive bladder cancer; non-muscle-invasive carcinoma of the urinary bladder) and moderate in high-grade tumors (undifferentiated or anaplastic malignant tissue). Therefore, it cannot be recommended in the early detection or screening of carcinoma of the urinary bladder because of the excessively high rate of false-negative findings.
- For the follow-up of high-grade tumors, cytology is particularly suitable due to the high specificity (probability that actually healthy people who do not suffer from the disease in question, are also detected as healthy in the test).
- The procedure is highly examiner-dependent.
About 40-50% of all diagnosed bladder carcinomas can be attributed to the well-differentiated manifestations (G1 tumors). In this tumor group, urine cytology has a detection sensitivity of only 40-50%. However, this means that urine cytology cannot detect about 25-30 % of all tumor patients.On the other hand, this method has a very high specificity (> 90 %) with a detection rate of > 80 % for undifferentiated tumors (G3 tumors).In a meta-analysis, cytology was reported to have a sensitivity (percentage of diseased patients in whom the disease is detected by use of the test, i.e., a positive test result occurs) of 40% and a specificity (probability that actually healthy individuals who do not have the disease in question are also detected as healthy by the test) of >90%, with a positive predictive value of >90%.
