In the following article, Timothy Gilligan, MD, answers a question posed by an attendee during a 2015 Best of ASCO® Meeting. Dr. Gilligan is a medical oncologist with the Cleveland Clinic.
Question: How would you treat adenocarcinoma of the bladder?
Answer: Adenocarcinoma (AC) of the bladder is a rare disease, representing 2% or fewer of all bladder neoplasms. However, in areas where infection with Schistosoma haematobium is endemic, nearly 10% of bladder cancers are primary nonurachal adenocarcinomas.1,2 Other risk factors for these malignancies are exstrophy and bladder augmentation.
Dr. Timothy Gilligan
The initial distinction is between primary AC of the bladder and metastatic AC to the bladder from other sites.3,4 This distinction is made both clinically (i.e., looking for a primary tumor in the lungs, colon, and other organs) and histopathologically. It is also critical to distinguish urachal from bladder AC and primary bladder AC from transitional-cell carcinoma with glandular differentiation.4 Several subtypes of primary bladder AC exist. Nonurachal AC can be further subdivided into enteric, mucinous, signet ring cell, clear cell, and not otherwise specified.
Studies of AC of the bladder have reported a poor prognosis, with 5-year survival rates ranging from 0% to 31%. ACs of the bladder are more likely than transitional-cell carcinomas to be diagnosed at an advanced stage, but they do not appear to have a worse prognosis when controlling for stage and grade.5 Urachal ACs have been reported to have a better prognosis. An analysis of Surveillance, Epidemiology, and End Results data of 1,525 patients with AC reported that, compared to nonurachal ACs of the bladder, urachal ACs had lower all-cause mortality (hazard ratio [HR] 0.56, 95% CI [0.38, 0.83]) and disease-specific mortality (HR 0.59, 95% CI [0.35, 0.98]).6 Median survival was 29 months versus 58 months. Signet ring and mucinous AC subtypes also have been reported to have poorer outcomes.7,8
The preferred treatment for both urachal and bladder AC is radical cystectomy and pelvic lymph node dissection without perioperative chemotherapy or radiation therapy. Resectable urachal ACs are typically treated with a partial cystectomy with an en bloc resection of the dome of the bladder, as well as the urachal remnant and umbilicus. Radiation therapy appears to be of limited utility in bladder AC, and little data exist to guide the use of chemotherapy. These patients should be offered participation in experimental protocols if systemic therapy is being considered. Whether platinum-based chemotherapy regimens offer net benefit or net harm to these patients is not clear.9