Bladder polyps are abnormal tissue growths that develop on the inner lining of the bladder, the organ responsible for storing urine. While the term “polyp” often suggests a benign condition, growths in the bladder require immediate and thorough evaluation due to the potential for malignancy. The decision to remove a bladder growth depends entirely on a careful assessment of its appearance, cellular structure, and potential to cause harm.
Defining Bladder Growths
The term “bladder polyp” is frequently used to describe any abnormal tissue mass protruding into the bladder cavity. Clinicians, however, classify these growths more accurately as urothelial neoplasms or tumors, as they arise from the urothelium, the specialized cell layer lining the urinary tract. Because these growths have the potential to be malignant, the majority must be removed to determine their exact nature.
These tumors are described based on their physical shape inside the bladder, primarily as either pedunculated or sessile. A pedunculated growth is connected to the bladder wall by a narrow stalk, often giving it a mushroom-like or papillary appearance. Conversely, a sessile growth is broad-based and flat, adhering closely to the bladder wall without a stalk.
The physical description provides initial clues about the growth’s behavior, but definitive diagnosis requires microscopic analysis of the cells. While true benign polyps, such as fibroepithelial polyps, are rare, the vast majority of growths are recognized as urothelial tumors with varying degrees of malignant potential. Removal is therefore a necessary step to distinguish a harmless anomaly from a potentially serious condition.
Assessing the Risk of Malignancy
The primary purpose of removing any bladder growth is to determine the risk of it being or becoming Urothelial Carcinoma (UC), the most common form of bladder cancer. Without a tissue sample, it is impossible to definitively determine if the growth is benign, low-risk, or high-risk cancer. The pathologist assesses two main characteristics: the grade, which describes how abnormal the cells look, and the stage, which describes how far the growth has penetrated the bladder wall.
Grading classifies the tumor cells as either low-grade or high-grade. Low-grade tumors generally have cells that look similar to normal bladder cells, tend to grow slowly, and are less likely to spread. High-grade tumors consist of cells that look very different from normal cells, are more aggressive, and carry a higher risk of recurrence and progression deeper into the bladder wall.
Staging uses the Tumour, Node, Metastasis (TNM) system to determine the extent of invasion. Growths are categorized as non-muscle-invasive bladder cancer (NMIBC) if they are confined to the inner lining (Ta), or have grown only into the layer beneath the lining (T1). A particularly aggressive, non-papillary, high-grade form called Carcinoma in Situ (CIS) is also classified as NMIBC (Tis), but it carries a high progression risk.
Muscle-invasive bladder cancer (MIBC) is a more serious classification, occurring when the tumor has grown into the detrusor muscle layer of the bladder wall (T2) or beyond. Sessile tumors, which are flat and broad-based, are statistically more likely to be high-grade and muscle-invasive compared to the typically low-grade, stalk-like papillary tumors. The tissue analysis from the removal procedure provides these precise details, which are necessary to guide subsequent treatment decisions and predict the outlook for the patient.
Treatment and Removal Procedures
For nearly all suspected bladder tumors, the initial and most important step is a surgical procedure called Transurethral Resection of Bladder Tumor (TURBT). This procedure is minimally invasive and is performed by inserting a specialized instrument, called a resectoscope, through the urethra and into the bladder. The resectoscope has a lighted camera and a wire loop that uses electricity to cut away the abnormal tissue from the bladder wall.
The TURBT procedure removes the visible growth and provides the tissue sample necessary for pathology to determine the precise grade and stage of the tumor. During the removal, the surgeon also uses fulguration, a technique that uses heat to cauterize the base where the tumor was attached. This helps control bleeding and destroy any remaining microscopic tumor cells.
If the pathology report confirms a non-muscle-invasive tumor, secondary treatments are often initiated directly into the bladder using a catheter, known as intravesical therapy. Patients with a high risk of recurrence or progression, typically those with high-grade or T1 tumors, often receive Bacillus Calmette-Guérin (BCG). This immunotherapy prompts the body’s immune system to attack the cancer cells. For low-risk tumors, or when BCG is not suitable, intravesical chemotherapy agents like Mitomycin C may be instilled into the bladder to reduce the chance of recurrence.
Post-Treatment Monitoring and Surveillance
Following the removal and any subsequent intravesical therapy, a rigorous schedule of post-treatment monitoring is necessary. Urothelial tumors have a high tendency to return, with recurrence rates for non-muscle-invasive bladder cancer reaching 70 to 80% within five years, even after successful initial treatment. The objective of surveillance is to detect any recurrence or progression to a more serious stage at the earliest possible time.
The cornerstone of this long-term management is the cystoscopy, which involves inserting a flexible camera into the bladder to visually inspect the lining. The timing of these follow-up procedures is based on the patient’s individual risk stratification determined by the initial TURBT pathology. The first follow-up cystoscopy is typically scheduled within three to four months of the initial resection, as the highest risk of recurrence occurs early.
Patients with low-risk tumors may have cystoscopies less frequently after the first year, potentially moving to yearly checks for several years if the initial checks are negative. Conversely, individuals with high-risk disease, such as high-grade or T1 tumors, require a much more intensive schedule, often undergoing cystoscopy every three to six months for the first few years.