Carcinoma in situ of the bladder: why is it underdetected?

PURPOSE OF REVIEW: The standard diagnosis of carcinoma in situ (CIS) of the bladder, based on white light cystoscopy and urine cytology, is limited because CIS can vary from normal-appearing mucosa to a lesion indistinguishable from an inflammatory process. Intravesical instillation of Bacillus Calmette-Guerin (BCG) remains first-line therapy; however, a significant proportion of cases persist or recur after BCG treatment. This review summarizes recent improvements in the detection and treatment of CIS.

RECENT FINDINGS: The new optical technologies improve CIS detection, with a potential positive impact on oncological outcomes. The usefulness of MRI-photodynamic diagnosis fusion transurethral resection in CIS detection is unclear and further studies are needed. BCG instillation remains the first-line therapy in CIS patients and seems to improve recurrence and progression rates, especially with the use of maintenance. Intravesical device-assisted therapies could be effective in both BCG-naïve and BCG-unresponsive CIS patients, but further studies are ongoing to clarify their clinical benefit. A phase II clinical trial with pembrolizumab has shown the potential effectiveness of immune checkpoint inhibitors in BCG-unresponsive CIS patients and further trials are ongoing.

SUMMARY: New optical techniques increase the CIS detection rate. BCG instillation remains the first-line treatment. Immune checkpoint inhibitors could be a future alternative in BCG-naïve and BCG-unresponsive CIS patients.