Urothelial carcinoma in situ is an early-stage cancer that originates in the lining of the urinary tract. This condition involves abnormal cell growth that remains confined to its original location. This article clarifies what urothelial carcinoma in situ means, how it is identified, and its treatment and subsequent care.
Understanding Urothelial Carcinoma In Situ
Urothelial carcinoma in situ (CIS) involves abnormal cell growth within the urothelium, the specialized tissue lining the urinary tract. Urothelial cells, also known as transitional cells, form a protective barrier that prevents urine from penetrating deeper tissues and can stretch as the bladder fills. The term “in situ” is Latin for “in its place,” signifying that the abnormal cells are found only in the innermost layer of the urinary tract lining and have not spread beyond this initial site.
This non-invasive characteristic distinguishes CIS from invasive cancer, where cells have penetrated deeper layers or spread to other parts of the body. Urothelial CIS is considered a high-grade, non-invasive malignancy, meaning the cells appear significantly abnormal under a microscope. While localized, urothelial carcinoma in situ has the potential to progress to invasive urothelial carcinoma if left untreated. This condition most commonly occurs in the bladder but can also be found in other parts of the urinary tract, including the renal pelvis, ureters, and urethra.
How Urothelial Carcinoma In Situ Is Diagnosed
Detecting urothelial carcinoma in situ often begins with the presence of symptoms, though some individuals may not experience any noticeable signs. Common symptoms that might prompt investigation include blood in the urine, which can appear pink, red, or brown, as well as changes in urinary habits such as increased frequency, urgency, or a burning sensation during urination. Because these symptoms can resemble those of less serious conditions like urinary tract infections, a thorough evaluation is essential.
A cystoscopy involves inserting a thin tube with a camera into the bladder through the urethra, allowing the doctor to visually examine the bladder lining for any abnormalities. Urine cytology is another key diagnostic tool, where a urine sample is examined under a microscope to detect the presence of cancer cells shed from the urinary tract lining. While urine cytology is sensitive for high-grade cells, it cannot definitively distinguish between in situ and invasive cancer.
A biopsy is the conclusive step for confirming urothelial carcinoma in situ and its non-invasive status. During a cystoscopy, small tissue samples are often removed from suspicious areas for microscopic examination. Pathologists examine these samples to identify atypical cells confined to the urothelium without invasion into deeper layers.
Treatment Options for Urothelial Carcinoma In Situ
Treatment for urothelial carcinoma in situ primarily focuses on eliminating abnormal cells and preventing progression to invasive cancer. A common initial step is transurethral resection of bladder tumor (TURBT), a surgical procedure performed through the urethra to remove visible abnormal tissue. Following TURBT, intravesical therapy is typically recommended, which involves delivering medications directly into the bladder using a catheter. This direct application minimizes systemic side effects compared to oral or injected medications.
Bacillus Calmette-Guérin (BCG) immunotherapy is the most frequently used and effective first-line intravesical treatment for urothelial carcinoma in situ. BCG is a weakened strain of bacteria that stimulates the body’s immune system to attack and destroy cancer cells within the bladder. Treatment typically begins with an induction course, involving weekly instillations for six weeks. For many patients, maintenance therapy, consisting of additional BCG instillations at regular intervals for up to three years, is recommended to reduce the risk of recurrence and progression.
If BCG is not suitable or effective, other intravesical chemotherapy agents may be used, such as mitomycin C or gemcitabine. These drugs work by directly killing cancer cells. Mitomycin C is often administered weekly for several weeks, similar to BCG.
Life After Diagnosis: Prognosis and Follow-up Care
While urothelial carcinoma in situ is initially non-invasive, it carries a significant risk of recurrence and progression to invasive bladder cancer if not carefully managed. Up to 40-60% of patients with urothelial CIS may develop invasive disease within five years of diagnosis.
Regular, lifelong follow-up care is a fundamental part of managing urothelial carcinoma in situ. This surveillance typically includes repeat cystoscopies to visually inspect the bladder lining for new or returning lesions. Urine cytology tests are also performed periodically to check for abnormal cells. These regular examinations are essential for detecting any recurrence or progression early, when treatment is most likely to be effective.