Urachal cancer: contemporary review of the pathological, surgical, and prognostic aspects of this rare disease.

Surgery is the mainstay of treatment for patients with urachal cancer (UraC). Still, one third of patients are un-resectable at presentation. Histology shows adenocarcinomas in the majority of cases with resemblance to enteric tumors. Standard chemotherapeutic regimens for bladder cancer have failed these patients. The role and efficacy of radiotherapy remains unclear due to its use in combination with chemotherapy or in a palliative setting. A lack of background knowledge about this disease leaves practitioners with unanswered questions when recommending (neo)adjuvant or palliative treatment options. Despite the lack of large multicenter series or randomized studies, independent case series have found commonalities with gastric, colorectal or ovarian cancers. Better clinical staging, advanced surgical techniques and a variety of (neo)adjuvant therapy combinations spawn hope for improved survival for these patients. Genetic and immunohistochemical studies are debating a common origin of this disease. Meta-analyses of clinical data are showing prognosticators and risk factors. UraC is a rare disease characterized by malignant degeneration of the urachal remnant with the highest incidence in fifty to sixty year old individuals. Unlike bladder cancer, the majority of UraC cases are adenocarcinomas. Its classical location at the bladder dome, advanced stage at presentation and symptoms like hematuria and mucinuria, should make the clinician suspicious. It is important to look for metastases or mucous cysts during clinical staging to determine the possibility of a curative approach. Up to date, surgery including on-bloc resection of the urachal ligament, the bladder dome and the umbilicus is the only proven cure. R0 resection is crucial for recurrence free survival. Adjuvant or palliative therapy can prolong survival in un-resectable or recurrent disease. While curative patients have a survival well above 50% over five years, palliative patients average only two years. Scientific knowledge about UraC is comprised of single center experiences, small collected cohorts or pathology/cancer registry database searches. Many questions like validated staging, (neo)adjuvant treatment options, differences in outcome for different tumor types and the existence of a common genetic origin are still unanswered. Future studies and trials are needed to address these important topics.