Master Zhang is nearly 70 years old and has been experiencing blood in his urine, urgency in urination and recently difficulty in urination for two years. Cancer indicators were also not high. He had been thought to be caused by inflammation of the urinary system and prostate hypertrophy. After the doctor inquired about his condition, he highly suspected that there was a urinary tract tumor, and after cystoscopy, he was found to have advanced bladder cancer. Bladder cancer is the most common malignant tumor in the genitourinary system, ranking 9th in incidence of malignant tumors worldwide, with a significantly higher incidence in men than in women. In Europe and the United States, bladder cancer can account for about 5%-10% of malignant tumors in men, and its incidence is on the rise with increasing age. Among bladder cancers, >90% belong to bladder uroepithelial cancer, of which >70% are non-muscle invasive bladder cancer, and the recurrence rate is as high as 30%-80% 5 years after tumor resection. Therefore, early diagnosis and detection of tumors are very important for the treatment of bladder cancer and reducing the recurrence rate after surgery. Bladder cancer is a malignant tumor that occurs on the bladder mucosa. 2012 incidence rate of bladder cancer in the national tumor registry area is 6.61/100,000, ranking 9th in the incidence rate of malignant tumors. Bladder cancer can occur at any age, even in children. Its incidence rate increases with age, with a high incidence age of 50-70 years. The incidence of bladder cancer in men is 3-4 times higher than that in women. Previously, the mucosal epithelium of the bladder was referred to as the migratory cells. In 1998, the WHO and the International Society of Urological Pathology jointly recommended the term uroepithelium instead of the term migratory cells to distinguish it from the migratory epithelium in the nasal cavity as well as in the ovaries, making uroepithelium the proper term for the urinary tract system. The pathological types of bladder cancer in the histological classification of tumors of the urinary tract system in the 2004 WHO Pathology and Genetics of Tumors of the Urinary System and Male Genital Organs include uroepithelial carcinoma of the bladder, squamous cell carcinoma of the bladder, adenocarcinoma of the bladder, and other rare types of clear cell carcinoma of the bladder, small cell carcinoma of the bladder, and carcinoid carcinoma of the bladder. The most common type of bladder cancer is uroepithelial carcinoma of the bladder, which accounts for more than 90% of all bladder cancer patients. The etiology of bladder cancer is complex, with both intrinsic genetic factors and extrinsic environmental factors. Two of the more clearly identified risk factors are smoking and occupational exposure to aromatic amine chemicals. Smoking is the most certain risk factor for bladder cancer. 30%-50% of bladder cancers are caused by smoking, and smoking can increase the risk rate of bladder cancer by 2-6 times, and the incidence of bladder cancer increases significantly as the time of smoking increases. Another important causative risk factor is related to a range of occupations or occupational exposures. It has been confirmed that aniline, diaminobiphenyl, 2-naphthylamine, and 1-naphthylamine are all carcinogens of bladder cancer, and long-term exposure to these chemicals increases the probability of bladder cancer, with occupational factors accounting for about 25% of all bladder cancer patients. Occupations associated with bladder cancer include industries such as aluminum products, coal tar, asphalt, dyes, rubber, and coal gasification. Clinical manifestations, the initial clinical manifestation of about 90% or more of patients with bladder cancer is hematuria, which usually presents as painless, intermittent, and full-blown hematuria with the naked eye, or sometimes microscopic hematuria. The hematuria may occur only once or last for one to several days and may reduce or stop on its own. Sometimes the coincidence of the patient taking medication and the hematuria stopping on its own often gives the illusion that the patient is “cured”. Some patients may experience a recurrence of hematuria after a period of time. The coloring of hematuria varies from light red to dark brown, often dark red, and some patients describe it as flesh-washing or tea-like. The amount of bleeding and the duration of hematuria are not necessarily proportional to the malignancy, size, extent and number of tumors. Sometimes the tumor is already large or advanced when hematuria occurs; sometimes a very small tumor presents with a large amount of hematuria. Some patients are found to have tumors in the bladder during ultrasound examinations during health checkups. In 10% of patients with bladder cancer, bladder irritation symptoms may first appear, manifesting as frequent urination, urgent urination, painful urination and difficult urination, while patients do not have obvious hematuria. This is mostly caused by tumor necrosis, ulceration, larger or more number of tumors in the bladder or diffuse infiltration of bladder tumor into the bladder wall, which reduces the bladder capacity or is complicated by infection. Tumors in the bladder triangle and bladder neck may obstruct the bladder outlet and symptoms of dyspareunia may occur. Diagnostically, at present, direct observation of the urinary epithelium by conventional white light cystoscopy remains the gold standard for the diagnosis of bladder cancer. In recent years, fluorescence cystoscopy has been widely used in clinical studies to improve the sensitivity of bladder cancer diagnosis. Several prospective randomized clinical trials have demonstrated that fluorescence cystoscopy improves the detection of bladder cancer, especially in stage Ta tumors and carcinoma in situ (CIS). Urine cytology continues to play an important role. Urine cytology is highly specific and highly sensitive, especially for low-grade tumors, but can be influenced by subjective observer factors. Urine tumor cells remain the current standard marker for the diagnosis and follow-up review of bladder cancer. The possibility of urologic tumors, especially bladder cancer, should be considered in the presence of painless meatus hematuria over 40 years of age. The patient’s past history, family history, combined with symptoms and physical examination should be integrated to make preliminary judgment, and further relevant examinations should be performed. The examination methods include routine urine examination, urinary exfoliative cytology, urinary tumor markers, abdominal and pelvic ultrasound, etc. Based on the results of these examinations, a decision will be made whether to perform cystoscopy, intravenous urography, pelvic CT or/and pelvic MRI, etc. to clarify the diagnosis. Among them, cystoscopy is the most prominent method to diagnose bladder cancer. For treatment, uroepithelial carcinoma of the bladder is divided into non-muscle invasive uroepithelial carcinoma and muscle invasive uroepithelial carcinoma. Patients with non-muscle invasive uroepithelial carcinoma are mostly treated with transurethral bladder tumor electrosurgery and postoperative treatment with bladder irrigation to prevent recurrence. Patients with muscle-infiltrating uroepithelial carcinoma and squamous and adenocarcinoma of the bladder are mostly treated by total cystectomy, and some patients can be treated by partial cystectomy. Patients with muscle-infiltrating uroepithelial carcinoma can also be treated with neoadjuvant chemotherapy + surgery first. Metastatic bladder cancer is mainly treated with chemotherapy. The commonly used chemotherapy regimens are M-VAP (methotrexate + vincristine + adriamycin + cisplatin) and GC (gemcitabine + cisplatin) and MVP (methotrexate + vincristine + cisplatin) regimens, which have an efficiency of 40%-65%. Prevention to reduce environmental and occupational exposures may reduce the risk of developing uroepithelial carcinoma. Approximately 70% of patients recur after transurethral electrodesiccation, and postoperative intravesical instillation of BCG or gemcitabine and docetaxel reduces the recurrence rate to 25%-40%. Commonly used chemotherapeutic agents for instillation are mitomycin, adriamycin, tiotipine, hydroxycamptothecin, etc. The 5-year survival rate after total cystectomy for patients with invasive bladder cancer is 60%-70%.