What Causes Bladder Cancer?

Bladder cancer is a malignant tumor that develops on the mucosa of the bladder. It is the most common malignant tumor of the urinary system and one of the ten most common tumors in the body. It occupies the first place in the incidence of urogenital tumors in China, and second only to prostate cancer in the west. In 2012, the incidence of bladder cancer in the national tumor registration areas was 6.61 per 100,000, ranking 9th in the incidence of malignant tumors. Bladder cancer can occur at any age, even in children. Its incidence increases with age, with a high incidence of 50 to 70 years. The incidence of bladder cancer in men is three to four times that of women. The bladder mucosal epithelium was previously referred to as transitional cells. In 1998, the WHO and the International Society of Urology recommended that the term urothelial be used instead of the term transitional cell to distinguish it from the transitional epithelium in the nasal cavity and ovaries, making the urothelial urine A proper term for road systems. The pathological types of bladder cancer in the histological classification of urinary tract tumors in the "Urology and Genetics of Tumors of the Urinary System and Male Reproductive Organs" by WHO in 2004 include bladder urothelial carcinoma, bladder squamous cell carcinoma, bladder adenocarcinoma, other rare There are also bladder clear cell carcinoma, bladder small cell carcinoma, and bladder carcinoid. Among them, the most common is bladder urothelial cancer, which accounts for more than 90% of the total number of bladder cancer patients. The bladder cancer is generally referred to as bladder urothelial cancer, which was previously called bladder transitional cell carcinoma.

Basic Information

English name

bladder cancer

Visiting department

Oncology, Urology

Multiple groups

Long-term smokers, people exposed to aromatic amine chemicals at work

Common causes

Etiology is complex, both genetic and external environmental factors

Common symptoms

Hematuria, bladder irritation, difficulty urinating, upper urinary tract obstruction, etc.

Causes of bladder cancer

The cause of bladder cancer is complex, both internal genetic factors and external environmental factors. The two clearer risk factors are smoking and occupational exposure to aromatic amine chemicals. Smoking is currently the most certain risk factor for bladder cancer. 30% to 50% of bladder cancer is caused by smoking. Smoking can increase the risk of bladder cancer by 2 to 6 times. With the extension of smoking time, the incidence of bladder cancer Also significantly increased. Another important risk factor for disease 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. Those who have been exposed to these chemicals for a long time have an increased probability of bladder cancer. It accounts for 25% of the total number of bladder cancer patients. Occupations related to bladder cancer include aluminum products, coal tar, asphalt, dyes, rubber, coal gasification and other industries.

Clinical manifestations of bladder cancer

About 90% of the patients with bladder cancer have an initial clinical manifestation of hematuria, which is usually painless, intermittent, gross hematuria, and sometimes microscopic hematuria. Hematuria may only occur once or last for 1 to several days, and it can be relieved or stopped on its own. Sometimes the coincidence of patients with hematuria after taking medication often gives the patient the illusion of "healing". Some patients may reappear hematuria after a period of time. The staining of hematuria ranges from light red to dark brown, often dark red, and some patients describe it as meat-washing and tea-like. The amount of bleeding and the duration of hematuria are not necessarily proportional to the malignancy, size, range and number of tumors. Sometimes gross hematuria occurs when the tumor is already large or advanced; sometimes small tumors have a large amount of hematuria. Some patients found a tumor in the bladder during a B-ultrasound during a health checkup. In 10% of patients with bladder cancer, bladder irritation symptoms first appear, which are frequent urination, urgency, dysuria, and difficulty urinating, and the patients have no obvious gross hematuria. This is mostly caused by tumor necrosis, ulcers, larger or more tumors in the bladder, or diffuse bladder tumors infiltrating the bladder wall, resulting in reduced bladder capacity or concurrent infection. Tumors in the triangular region of the bladder and the neck of the bladder can obstruct the exit of the bladder and cause symptoms of dysuria.

Bladder cancer diagnosis

For painless gross hematuria over 40 years of age, the possibility of urinary tumors, especially bladder cancer, should be considered. Based on the patient's past history, family history, combined with symptoms and physical examination to make a preliminary judgment, and further relevant examinations. Examination methods include routine urine tests, urinary shedding cytology, urinary tumor markers, and abdominal and pelvic ultrasound examinations. According to the results of the above examination, decide whether to perform cystoscopy, intravenous urography, pelvic CT or / and pelvic MRI to confirm the diagnosis. Among them, cystoscopy is the most important method for diagnosing bladder cancer.

Bladder Cancer Treatment

Bladder urothelial carcinoma is divided into non-muscle invasive urothelial carcinoma and muscle invasive urothelial carcinoma. Most patients with non-muscle invasive urothelial carcinoma undergo transurethral resection of the bladder tumor, and postoperatively use bladder perfusion to prevent recurrence. Patients with muscular invasive urothelial carcinoma, bladder squamous cell carcinoma, and adenocarcinoma are mostly treated with total cystectomy, and some patients can be treated with partial cystectomy. Patients with muscular invasive urothelial carcinoma can also be treated with neoadjuvant chemotherapy + surgery. Chemotherapy is mainly used for metastatic bladder cancer. Commonly used chemotherapy regimens are M-VAP (methotrexate + vinblastine + doxorubicin + cisplatin), GC (gemcitabine + cisplatin) and MVP (methotrexate + Vinblastine + cisplatin), the effective rate of chemotherapy is 40% to 65%.

Prognosis and prevention of bladder cancer

Reducing environmental and occupational exposure may reduce the risk of urothelial cancer. About 70% of patients have recurrence after transurethral resection. Postoperative bladder perfusion or chemotherapy can reduce the recurrence rate to 25% to 40%. Commonly used perfusion chemotherapy drugs are mitomycin, doxorubicin, tiotepa, hydroxycamptothecin and the like. The 5-year survival rate of patients with invasive bladder cancer after total cystectomy is 60% to 70%.