FISH Testing from Urine Samples May Predict Risk of Cancer Progression in Patients with Superficial Bladder Cancer
According to a recent article published in the Journal of Urology , laboratory testing (referred to as fluorescence in situ hybridization (FISH)) from a urine sample in patients with superficial bladder cancer may help predict a patient’s response to therapy, as well as their risk of developing more advanced disease. Patients who are at an increased risk of progressive cancer may wish to undergo more aggressive therapy than their counterparts.
Bladder cancer is a common cancer, with approximately 55,000 new cases diagnosed in the United States each year. Superficial bladder cancer refers to cancer that remains localized within the outermost (most superficial) layers of the bladder and has not spread to deeper layers of the bladder. Patients with superficial bladder cancer are routinely treated with surgical removal of the cancer followed by additional (adjuvant) therapy to decrease the risk of recurrent cancer or progression to more invasive disease. Despite standard treatment, many patients with superficial bladder cancer experience a recurrence of their cancer. Following the removal of the cancer, patients with superficial bladder cancer are usually treated with adjuvant intravesicle chemotherapy (placement of the drug directly into the bladder), which often consists of mitomycin C or Bacille Calmette-Guérin (BCG). While this therapy is beneficial, recurrences are common, and a substantial portion of patients will ultimately develop more advanced disease. Therefore, patients undergo routine and sometime frequent monitoring, often in the form of a cystoscopy, a procedure in which a lighted tube is inserted into the bladder. Due to the invasiveness of this procedure, as well as the time and financial commitments for patients to undergo cystoscopies, researchers are evaluating other ways in which to monitor recurrences or predict patients who are at a high risk of developing more advanced disease. These patients may wish to undergo more aggressive therapies to reduce their risks and improve their long-term outcomes.
Researchers from the Mayo Clinic recently conducted a clinical trial to evaluate the accuracy of FISH testing of urine samples in patients with superficial bladder cancer. FISH testing includes laboratory measures to determine if specific abnormal cells are present in the urine. This trial included 37 patients with superficial bladder cancer who were undergoing intravesicle therapies with BCG or other therapies. Urine samples and FISH testing were performed prior to therapy, as well as following therapy, and were compared to results of standard testing procedures. Post-therapy FISH results included 25 patients with normal (negative) results and 12 patients with detection of abnormal cells (positive results). All patients with positive post-therapy FISH results experienced a cancer recurrence, while only 13 of the 21 patients with negative post-therapy FISH results experienced a cancer recurrence. Importantly, patients with a positive post-therapy result were at a 9.4-fold increased risk for developing more advanced (muscle-invasive) bladder cancer and 75% of patients with positive FISH results both pre- and post-therapy eventually developed muscle-invasive bladder cancer.
The researchers concluded that FISH testing of urine samples in patients with superficial bladder cancer undergoing intravesicle therapy can help predict the risk of a cancer recurrence or the risk of developing a more advanced form of cancer. Patients at a high risk of developing more advanced cancer may wish to undergo more aggressive therapy in the hopes of improving long-term outcomes. Patients with superficial bladder cancer may wish to speak with their physician about the risks and benefits of participating in a clinical trial further evaluating urinary FISH testing or other non-invasive screening methods. Sources of information regarding ongoing clinical trials include the National Cancer Institute (cancer.gov).
Reference: Kipp B, Karnes J, Brankley S, et al. Monitoring Intravesicle Therapy for Superficial Bladder Cancer Using Fluorescence in situ Hybridization. Journal of Urology. 2005;173:401-404.