For muscle-invasive bladder cancer with regional lymph node metastases, cure is possible if treated promptly and appropriately. Some patients with superficial but highly invasive bladder cancer may eventually die from metastases despite total bladder resection. In situ neobladder surgery is feasible for most patients who must have their bladder removed, whether male or female. Patients with in situ neobladder have a relatively high quality of life; therefore, for some patients with highly invasive superficial bladder cancer, total cystectomy is a reasonable option that is not limited to conservative therapies. Smoking ranks first among the risk factors for bladder cancer, including secondhand smoke. There are a number of occupations that require long-term exposure to chemicals containing aromatic hydrocarbons, which also increase the risk of bladder cancer, typically in the dye, leather, paint and aluminum industries. Other risk factors include specific drugs, especially cyclophosphamide. A recent epidemiological survey showed that the use of hair dyes (especially for hairdressers) is a risk factor for the development of bladder cancer. The staging, treatment and prognosis of bladder cancer depend on the depth of bladder infiltration. At the time of diagnosis, 75% of bladder cancers are superficially located (invading only the mucosal layer of the bladder surface), and most of these patients are at low risk of tumor progression and metastasis. However, in about 25% of patients, the bladder cancer has already infiltrated the muscular layer of the bladder at the time of the first visit, and the ideal treatment is complete removal of the bladder and surrounding lymph nodes, i.e., radical cystectomy combined with expanded lymph node dissection. Types of bladder cancer There are three main pathological types of bladder cancer: metastatic cell carcinoma (more than 90%); squamous cell carcinoma (3-8%), where schistosomiasis, chronic infection and inflammation are risk factors for the development of squamous carcinoma; and adenocarcinoma (1-2%), which is very close in morphology to intestinal tumors and therefore needs to be differentiated from intestinal metastases. Squamous and adenocarcinoma almost always show invasive growth at the time of diagnosis. The prognosis of adenocarcinoma is worse than that of metastatic cell carcinoma. Neuroendocrine tumors of the bladder are rare, accounting for 1% of cases, and are histologically differentiated between large and small cells, with a mixture of both in half of cases; even with aggressive surgical treatment and chemotherapy, the prognosis is poor. Staging of bladder cancer The staging of bladder cancer depends mainly on the specimen obtained during TURBT (transurethral resection of bladder tumor). Treatment options depend on the malignancy of the tumor (pathologic grading) and the level of bladder invasion (pathologic staging). In order to determine the presence of muscle infiltration, the muscle below the base of the tumor must be accessed during resection. What is often referred to as “superficial” or non-invasive bladder cancer, which occurs in the mucosal layer (or innermost layer) of the bladder wall, can usually be completely removed by TURBT. If the tumor invades the connective tissue beneath the mucosa, the lamina propria (stage T1), then special attention is needed, as 30% of these tumors will be found to be infiltrated by the muscularis muscle upon re-excision. Intravesical perfusion chemotherapy can be used as long as there is sufficient myxoid tissue in the specimen to confirm the absence of myxoid infiltration. The gold standard of treatment for bladder cancer with muscle infiltration is radical cystectomy as opposed to bladder cancer without muscle infiltration, which is completely different. Radical cystectomy provides accurate staging of bladder cancer and tumor-associated regional lymph node conditions with the best local tumor control and long-term tumor-free survival; it also helps to accurately assess the risk and the need for adjuvant chemotherapy. Chemotherapy and radiotherapy are mainly used to treat patients who have lost the chance of surgery. Surgery For high-grade invasive bladder cancer, the standard treatment is radical bladder resection plus bilateral pelvic and iliac vascular lymph node dissection. Most studies have shown that for muscle-invasive bladder cancer, bladder-preserving treatments (transurethral electrodesiccation, chemotherapy, and radiation therapy) are less effective than radical cystectomy in terms of local recurrence and survival. With improvements in surgical techniques and postoperative treatment measures, surgical mortality and complications (e.g., sexual dysfunction) have decreased significantly. Male patients require complete removal of the bladder, prostate, seminal vesicles, and pelvic lymph nodes. In women, traditional radical cystectomy (or anterior pelvic organ resection) requires complete removal of the bladder, uterus, fallopian tubes, ovaries, and anterior vaginal wall, and is still required for some patients. In contrast, some patients can have their pelvic organs and vagina preserved while ensuring that cancer control is not compromised. Radical cystectomy to treat muscle-invasive bladder cancer has the highest survival rate and lowest local recurrence rate. The progression-free survival and overall survival rates of bladder cancer are significantly correlated with the pathologic stage of the tumor, and the 5-year overall survival rate is about 50%. Patients with no lymph node metastasis and tumors confined to the bladder have a 5-year survival rate of about 80%, compared to 35-58% if the tumor breaks through the bladder into the peribladder fat or if there is lymph node metastasis. It is worth emphasizing that for patients with lymph node metastases, radical cystectomy and expanded pelvic lymph node dissection can result in long-term survival in 35%. Survival advantage of lymph node dissection The first place where bladder cancer metastasizes is in the pelvic lymph nodes. Although there is no clear definition of the extent of expanded lymph node dissection, a growing body of data suggests that patients who are candidates for surgery should undergo more extensive lymph node dissection. Expanded lymph node dissection should include not only the distal para-aortic and inferior vena cava lymph nodes, but also the presacral lymph nodes, which anatomically also receive bladder lymphatic drainage and therefore have the potential for tumor metastasis to this area. Expanded lymph node dissection can improve survival in patients with/without lymph node metastases without significantly increasing surgical complications and mortality. In patients with total bladder dissection with lymph node metastases, the extent of the primary bladder tumor (p-stage), the number of lymph nodes removed, and the metastasis of the lymph nodes are important indicators of prognosis.