Urine cytology is useful in the diagnosis of bladder cancer for several reasons. The discussion below is one application. Another way I use cytology is in the patient with blood in their urine but they don’t want to commit to cystoscopy. If the cytology is wnl, it is unlikely that the patient has a bladder cancer. One caveat: Low grade TCC of the bladder may be missed with cytology alone, but some make the case that this “non aggressive” form of bladder cancer will do little harm anyway. This is where the “art of medicine” comes in!
Most unnecessary biopsies of erythematous bladder lesions can be avoided by guidance of urine cytology.
Background: Bacillus Calmette-Guérin (BCG) is recommended for non–muscle-invasive bladder cancer (NMIBC). However, treatment often causes bladder irritation and may result in erythematous lesions on cystoscopy. Distinguishing benign from malignant lesions is challenging. Urine cytology may provide a way to differentiate lesions that should be biopsied compared to those that can be observed.
Objective: To evaluate the benefit of urine cytology in patients with erythematous bladder lesions after BCG therapy.
Participants: NMIBC patients treated with ≥1 BCG instillations between 2009 and 2015 from 2 Finnish hospitals.
Methods: The biopsy histology was evaluated according to the cystoscopic appearance of tumor growth or erythematous lesions. Urine cytology results were also evaluated. Based on biopsy pathology, cytology was evaluated to determine sensitivity, specificity, and positive predictive values (PPVs) and negative predictive values (NPVs).
Results: BCG treatment was provided to 206 patients, of whom 159 (76%) underwent a biopsy or resection. A total of 367 lesions were evaluated, of which 209 were erythematous lesions. Benign pathology was found in 187 (89.5%) erythematous lesions. As compared to papillary or flat lesions, cytology was most accurate for erythematous lesions with a sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of 59%, 76%, 94%, and 23%, respectively.
Conclusions: In patients undergoing BCG therapy, a negative cytology might provide reassurance when considering biopsy of an erythematous lesion.
Reviewer’s Comments: BCG therapy is a proven treatment for patients with intermediate- and high-risk NMIBC. However, treatment often results in bladder irritation and discomfort. On follow-up evaluation, erythematous lesions are often present. Many are benign, but some represent residual malignancy. Understanding the benefit of urine cytology may prevent biopsy in patients who are otherwise responding to therapy. This study was a 2-center Finnish study of patients undergoing biopsy following treatment with BCG. Urine cytology results were compared to biopsy pathology depending on biopsy of either tumors (papillary or flat) or erythematous lesions. Accuracy of cytology was evaluated using sensitivity, specificity, NPV, and PPV. The study comprised 206 patients undergoing BCG treatment; 159 had a biopsy of 367 total lesions. Erythematous lesions represented the majority of biopsies; 10% proved to be malignant on pathologic examination. As compared to biopsies of papillary or flat tumors, urine cytology was most consistent with biopsy result for erythematous lesions. For patients undergoing BCG for NMIBC, biopsy or resection is warranted for all patients with papillary or flat tumors. For those with erythematous lesions, cytology may be used to determine the benefit of biopsy. Patients with a negative urine cytology might be eligible for monitoring without biopsy.(Reviewer–Kelly Stratton, MD).
Article Reviewed: Urine Cytology Is a Feasible Tool in Assessing Erythematous Bladder Lesions After BCG Treatment. Pertti N, Otto E, et al: BJU Int; 2018; (June 29): epub ahead of print.