Among men in the United States, bladder cancer is the fourth most common malignancy after prostate, lung, and colorectal cancers, with an estimated 68,810 new cases and approximately 14,100 patient deaths from the disease in 2008 [1]. And in China, bladder cancer is the most common malignant tumor of the urinary system. Bladder cancer has the highest recurrence rate among all malignancies, with 10% to 67% of patients recurring within 12 months after transurethral resection of bladder tumor (TURBT) and 24% to 84% of patients recurring within 5 years after surgery. However, bladder tumors are also characterized by low malignancy and long survival time. Many patients, due to multiple recurrences, need multiple surgeries and numerous reviews, which not only have high medical costs and painful examinations, but also cause serious psychological burden. For example, in the United States, although prostate cancer is common, bladder cancer costs more than twice as much as prostate cancer, up to$2.02 billion. In addition, due to multiple recurrences, longer survival and higher follow-up rates, a wealth of information can be accumulated, which is valuable for exploring the recurrence pattern of tumors. The recurrence of bladder tumor is related to a variety of clinical factors, the most important of which is the grading and stage of the tumor. Other factors, such as the number of tumors, tumor size, previous recurrence rate, and whether it is accompanied by carcinoma in situ, are also important factors affecting recurrence. According to the above factors bladder cancer can be classified into low risk group: single,TaG1,≤3cm in diameter; high risk group: T1G3,multicentric,or high recurrence,Cis; intermediate risk group: all other types of tumors,Ta-1,G1-2,multiple,>3cm in diameter [2]. The risk of recurrence of bladder cancer varies by risk level, with one-year recurrence rates of 15-61% and five-year recurrence rates of 31-78%. Therefore, attention should be paid to the accurate and detailed description of the above factors during clinical cystoscopy, surgery, and pathological examination. For example, in transurethral resection of bladder tumors, the resected specimen must include the muscular layer, otherwise it will not be possible to identify the stage of the tumor as Ta, T1, or T2. Larger tumors may be surrounded by carcinoma in situ, and the mucosa surrounding the tumor should be resected separately for examination. The three resected components of a large tumor, tumor tissue, muscle layer tissue and peritumor tissue, should be sent separately for examination. When resecting, cautery should be avoided as much as possible. Necrotic and cauterized tissue may affect the staging and grading. 1973 histologic grading of bladder cancer was classified into 3 grades of highly differentiated, moderately differentiated and poorly differentiated according to the degree of differentiation of cancer cells, using gradel, 2 and 3, respectively. 2004 WHO published a new grading method, which classifies uroepithelial tumors into low malignant tendency uroepithelial papillary tumors, low grade and high grade uroepithelial The new grading method classifies uroepithelial tumors into low grade uroepithelial papillary tumors, low grade and high grade uroepithelial carcinomas. A variety of guidelines mostly recommend the WHO (2004) grading method, and no new recurrence rates of different graded tumors have been reported, and research in this area should be strengthened. Bladder tumors are polygenic abnormal lesions and their occurrence is related to multiple genes, and these same genes also influence the recurrence of tumors. Mutations in TP53, P15, P16, RB, erb-b2, p21-ras, c-myc, c-jun and other genes have been found to be associated with the development of bladder cancer. In addition aberrations of chromosomes 3, 5, 9, 7, 11 and 17 and microsatellite instability also affect tumor recurrence. The following tumor markers found in urine, such as bladder tumor antigen and nuclear matrix protein 22, can be used for early diagnosis and early detection of tumor recurrence. Tumor markers discovered in recent years, such as telomerase, survivin, hyaluronan and hyaluronidase, mucin-7, nuclear matrix protein (BLCA-4), microsatellite sequence analysis and single nucleotide polymorphism analysis, have shown high sensitivity and specificity in studies for the diagnosis of bladder cancer and can be used for tumor follow-up and recurrence diagnosis. The occurrence and recurrence of bladder tumors may be related to mutations in multiple genes. A single gene or tumor marker test has limited value in diagnosing and predicting tumor recurrence and should be used in combination, and gene chip technology may be a good solution. The detection of VEGF, PCNA, MVD and other indicators can predict tumor recurrence, single indicator has little value and should be analyzed comprehensively. There have been many studies to confirm that there are different degrees of tumor remnants after the first electrosurgery. There are four possible factors for tumor recurrence, incomplete TUR, neglected lesions, intraoperative tumor implantation, and development of microscopic lesions into sarcoid lesions. A comprehensive analysis of re-TUR tumor residual rate was reported in one report as 33-76% with an increased tumor stage of 2-29% [3]. Some scholars advocate routine re-TUR, while opponents argue that re-TUR can cause tumor implantation, which can lead to tumor progression to the muscular layer and an increased rate of hematologic and lymphatic metastases. The residual rate of tumor can be reduced by improving the TUR technique. EAU guidelines suggest that re-TUR should be reconsidered when the first TUR is incomplete. Examples include larger tumors, multiple tumors, sent specimens that do not contain muscle tissue, high-grade non-myeloablative infiltrating tumors, or first TUR diagnosis of stage T1 tumors. The second TUR can reduce the postoperative recurrence, but more attention should be paid to the first TUR. if the resection can be exactly to the deep muscle layer and the peripheral resection is sufficient in scope, there is no need to perform another TUR. if it is difficult to clarify the muscle layer tissue under the electroscope, if necessary, intraoperative muscle layer biopsy can be performed to clarify that the base is muscle tissue, and there is no need to perform another TUR operation after surgery. Routine review at three months after surgery can fully detect tumor recurrence due to various reasons at an early stage without causing delay in diagnosis and treatment. To prevent bladder tumor recurrence, bladder irrigation chemotherapy can be used. The options are immediate postoperative bladder perfusion chemotherapy, early postoperative bladder perfusion chemotherapy and maintenance bladder perfusion chemotherapy and BCG bladder perfusion chemotherapy. For intermediate-risk and high-risk non-muscle invasive bladder cancer, after immediate postoperative bladder perfusion therapy within 24 hours, continued bladder perfusion chemotherapy is recommended once a week for 4 to 8 weeks, followed by maintenance bladder perfusion chemotherapy once a month for 6 to 12 months. The duration of perfusion is still controversial. Maintenance perfusion therapy for non-muscle invasive bladder cancer does not continue to reduce the probability of tumor recurrence at 6 months or more, and some studies have found that maintenance perfusion for 1 year reduces the probability of bladder tumor recurrence. Commonly used drugs for bladder perfusion chemotherapy include adriamycin, epirubicin, mitomycin, pirarubicin, and hydroxycamptothecin. Different physicians have different choices, and there is no uniform protocol as to which drug is most effective and what the optimal drug concentration is. What kind of drugs and what kind of regimen should be taken for different patients with recurrence risk tumors need further research and optimization. A bladder cancer database should be established to strengthen follow-up efforts, explore the pattern of bladder cancer recurrence, and prevent bladder cancer recurrence after surgery. In view of the multicenter occurrence of bladder tumors, the possibility of tumors in the upper urinary tract should be considered at the same time during the follow-up of bladder tumors, and corresponding examinations should be performed. What bladder tumors are prone to upper urinary tract tumors, how risky they are, the frequency of review, and what tests should be taken need further study. In the early diagnosis of bladder tumor recurrence, screening for tumor markers, especially in combination with multiple applications, may have important value. Multiple markers have different values, and how to apply them in combination and how many to choose needs further study. Cystoscopy has an irreplaceable value in the follow-up of bladder tumors. 5-aminolevulinic acid (5-ALA) fluoroscopy can detect small tumors, atypical hyperplasia or carcinoma in situ that are difficult to detect with ordinary cystoscopy. The earliest recommendation for cystoscopic review was monthly, but later it was set to every three months, dating back to at least 1936. The reason for the three-month rule has not been specifically reported in the literature. The American Urological Association recommends cystoscopy review every three to six months for three years and annually thereafter [4]. Similar recommendations are available from the National Comprehensive Cancer Network. It has been suggested that for low-grade stage Ta tumors, the frequency of review can be appropriately reduced if the tumor is completely removed and the cystoscopic review is negative after three months. It is clearly inappropriate to adopt the same follow-up protocol for all tumor patients regardless of the risk of recurrence, and further in-depth studies should be conducted to establish individualized follow-up protocols. There are several mechanisms regarding the recurrence mechanism of bladder cancer as follows. (1) The multicentric lesion theory. (2) Tumor implantation theory. (3) Immunosuppression theory. (4) Lesion residual theory. In addition to these factors as the causes of bladder cancer recurrence after surgery, the stimulation of carcinogenic substances in urine may be the direct cause of bladder cancer recurrence after surgery. Little is known about urinary carcinogens triggering bladder cancer. Research on urinary carcinogens in bladder cancer patients should be emphasized and strengthened to explore the mechanism of bladder cancer occurrence and recurrence, so as to change the composition of patients’ urine and prevent recurrence of bladder cancer. Along with the progress of molecular biology and the improvement of examination means, human beings are facing many new confusions in medicine. The development of molecular biology and the progress of examination means do not bring revolutionary progress in the treatment of diseases, and we must handle the thousands of complicated information coming to us with a new thinking macroscopic perspective to draw scientific conclusions and decisions. The Chinese Society of Urology has established the Bladder Cancer Collaborative Group and a tumor follow-up database, which provides the basis for large-scale, multicenter, randomized, controlled, prospective studies and offers the possibility of comprehensive use of patient information. An artificial neural network, based on the database, can provide a cost-effective optimal follow-up protocol, where the interval between cystoscopy and cytology may be adjusted depending on the patient’s risk of recurrence, rather than being fixed. Such empirical models have been used to provide successful nonlinear follow-up strategies. Neural networks can predict the risk of tumor recurrence and progression, improve diagnostic tools, optimize treatments, and change traditional follow-up strategies.