The appearance of any abnormal growth in the bladder, commonly referred to as a “bladder polyp,” understandably causes concern about cancer. These growths are masses or tumors projecting from the bladder lining, requiring immediate medical evaluation. While the term “polyp” suggests a benign growth like those found in the colon, the reality in the bladder is more complex and often points toward malignancy.
Understanding Bladder Growths and Malignancy Rates
The lay term “bladder polyp” is generally used by medical professionals to describe any visible tumor or mass originating from the urothelium, the lining of the bladder. True, isolated, non-cancerous growths, such as fibroepithelial polyps or inverted urothelial papillomas, are rare findings in the adult population. The vast majority of growths discovered are Urothelial Carcinomas (UC), which are cancers arising from the cells that line the urinary tract.
These cancerous growths are broadly categorized based on how deeply they have invaded the bladder wall. Non-Muscle Invasive Bladder Cancer (NMIBC) accounts for approximately 70% to 75% of all new bladder cancer diagnoses and is confined to the inner lining or the connective tissue just beneath it. NMIBC is highly treatable and has a favorable five-year survival rate, but it is characterized by a high rate of recurrence, meaning new growths often appear later.
The remaining cases are classified as Muscle-Invasive Bladder Cancer (MIBC), which is a more aggressive form that has spread into the deep muscle layer of the bladder wall. The distinction between NMIBC and MIBC is a significant factor in determining the necessary treatment and long-term prognosis for the patient.
Key Factors That Increase Risk
Bladder growths form when carcinogens cause DNA damage to the urothelial cells, leading to abnormal, uncontrolled cell growth. Smoking is recognized as the single most significant risk factor for developing urothelial cancer, causing about half of all bladder cancer cases. The toxic chemicals from tobacco are absorbed into the bloodstream, filtered by the kidneys, and then accumulate in the urine where they directly contact the bladder lining.
Beyond tobacco use, long-term occupational exposure to certain industrial chemicals also raises the risk of developing these growths. Workers in industries such as those involving dyes, rubber, leather, and petroleum products may be exposed to aromatic amines, which are known carcinogens that can accumulate in the bladder. The risk is especially high for individuals who both smoke and have these workplace exposures, as the two factors can act synergistically.
Chronic inflammation and irritation of the bladder lining are additional contributing factors to the formation of abnormal cells. Conditions such as recurrent urinary tract infections, the long-term use of indwelling urinary catheters, or chronic irritation from bladder stones have been linked to an increased risk. In specific regions of the world, infection with the parasitic worm Schistosoma haematobium is also a known cause of bladder cancer, particularly the less common squamous cell type.
Diagnosis and The Importance of Surveillance
When a bladder growth is suspected due to symptoms like blood in the urine, the diagnostic process begins with non-invasive tests such as urine cytology. The gold standard for initial detection is cystoscopy, a procedure where a thin scope with a camera is inserted through the urethra into the bladder to visually inspect the lining.
If a growth is detected during cystoscopy, a procedure called Transurethral Resection of Bladder Tumor (TURBT) is necessary to confirm the diagnosis and provide initial treatment. This procedure involves surgically removing the entire visible tumor, or a sample of it, for pathological analysis to determine the exact type, grade, and stage of the growth. Only through this tissue biopsy can the physician definitively classify the mass as non-cancerous, low-grade NMIBC, or the more aggressive MIBC.
Following initial treatment for NMIBC, ongoing monitoring is mandatory because of the high likelihood of recurrence. Patients are placed on a regular surveillance schedule involving repeated cystoscopies to check for new growths. This is crucial for early detection and successful long-term management, catching any new or recurring tumors before they can progress to a more advanced stage.