Background Superficial urothelial carcinoma (SUC) of the bladder is a common urinary tract tumor in China.There is a high recurrence rate of this tumor even after surgery and intravesical instillation.Previous reports have described a suppression of the immune system in cancer patients.Dendritic cells (DCs) play a pivotal role in the induction of an effective antitumor immune response.The aim of this study was to investigate the effects of surgery and epirubicin intravesical chemotherapy (IC) on peripheral blood DCs in subsets of patients with bladder SUC.Methods A total of 66 SUC patients and 38 healthy controls were enrolled in this study.All the patients had undergone transurethral resection (TUR) of their cancer and adjunctive IC after tumor removal.The patients were divided into a non-recurrence group (n=40) and a recurrence group (n=26) based on the presence or absence of tumor recurrence.Blood samples were taken preoperatively (PreOP),on postoperative days (POD) 1 and 7,and at postoperative month (POM) 3.Flow cytometric analysis was used for the determination and quantitation of the surface markers CD80 and CD86 in circulating DC subsets.Results The preoperative percentages of myeloid dendritic cells (mDCs) and expression of CD80 and CD86 were impaired in SUC patients compared to healthy controls (P <0.05).The percentages of mDCs and these surface markers decreased significantly on POD 1 and increased on POD 7,remaining higher than the preoperative values in POM 3 (P <0.05).The percentages of mDCs,and CD80 and CD86 in the non-recurrence group on PreOP,POD 7,and POM 3 were higher than those in recurrence group.Conclusions Surgical removal of SUC and adjunctive IC were associated with improved circulating mDC counts and function.Persistent depression of mDC counts and function after treatment in recurrence patients indicated lower antitumor immunity that may lead to tumor recurrence.