膀胱癌

　　膀胱癌的发病是一个多因素混合、多基因参与、多步骤形成的过程，异常基因型的积累加上外在环境的作用最终导致恶性表型的出现。其具体发病原因如下所述。

　　1、饮水中的致癌物：饮用经氯消毒并且含有氯化副产物的自来水，可使膀胱癌危险性增加。中国台湾和南美阿根廷的饮用水中的砷污染也与膀胱癌危险性增加有关。

　　2、咖啡：饮咖啡者的膀胱癌危险性高于不饮者，但两者无剂量和时间趋势，流行病学研究的结果已排除咖啡与膀胱癌之间的强相关性，但不排除两者之间相关。

　　3、尿道疾病：尿道上皮长期受到慢性刺激或人体代谢产物使尿中致癌物水平增高，可使尿路上皮增殖后癌变，例如膀胱鳞癌与埃及血吸虫感染或膀胱结石有关。

　　4、药物：大量服用含非那西汀的止痛药可使膀胱癌危险性增加，目前该药已停售。用环磷酰胺治疗的淋巴瘤患者膀胱癌发病的危险性可增高几倍，且肿瘤常为浸润性。

　　5、人工甜味剂：70年代末的研究报道甜味剂可使男性膀胱癌危险性增加60%，但此后的研究未能证实该相关性，故目前国际癌症研究机构已不再将甜味剂列入人类膀胱癌的致癌物质。

　　6. Family history:The risk of bladder cancer in direct relatives of patients with bladder cancer is about twice that of individuals without family history, and the risk in young bladder cancer patients is even higher.

　　Common complications of bladder cancer include bladder pain, severe hematuria, urinary retention, etc. The metastatic pathways of bladder tumors include lymphatic, blood, direct spread, and direct implantation of tumor cells. Lymphatic metastasis is the most common pathway, and bladder cancer can metastasize to the iliac internal, iliac external, obturator lymph node groups, or even to the iliac common lymph nodes. Some people point out that the iliac internal and obturator lymph nodes are the first station lymph nodes for bladder cancer metastasis.

　　Bladder cancer metastasis through blood vessels is common in advanced cases, most often in the liver, followed by the lung and skeleton. Skin, adrenal glands, kidneys, pancreas, heart, testicles, salivary glands, ovaries, muscles, and gastrointestinal tract have been reported, but all account for a small number.

　　Bladder cancer direct spread often occurs in the prostate or posterior urethra. Bladder cancer can extend to the outside of the bladder and form fixed masses with pelvic adhesions, or spread to the mucosa at the top of the bladder.

　　Complications after bladder cancer surgery include bleeding, pelvic infection, rectal injury, anuria, and wound rupture. Post-radiotherapy complications include rectal stenosis, rectal perforation, intestinal adhesion, intestinal obstruction, and small intestinal perforation. Complications of arterial infusion chemotherapy include refractory burning pain in the buttocks or thigh, vascular rupture, and others.

　　Typical symptoms of bladder cancer include hematuria, bladder irritation symptoms, urinary tract obstruction symptoms, etc. In the late stage, when the tumor invades the surrounding tissues and organs of the bladder or has pelvic lymph node metastasis, it can cause symptoms such as bladder area pain, urethrovaginal fistula, lower limb edema, and so on. When distant metastasis occurs, symptoms such as organ dysfunction of the metastatic organs, bone pain, and cachexia may also occur. The specific clinical manifestations are described as follows.

　　1. Hematuria:Hematuria without pain is the most common symptom, occurring in more than 80% of patients, among whom 17% have severe hematuria, but 15% may only have microscopic hematuria at the beginning. Hematuria is often intermittent, can also be initial or terminal hematuria, and some patients may pass blood clots or necrotic tissue. The duration and amount of hematuria are related to the malignancy, stage, size, number, range, and morphology of the tumor, but not necessarily proportional. In situ cancer often manifests as microscopic hematuria, and hematuria in bladder urachal cancer may not be obvious. Bladder tumors of non-urothelial origin may not have hematuria if the lesion has not penetrated the bladder mucosa.

　　2. Bladder irritation symptoms:Frequent urination, urgency, and dysuria, accounting for about 10%, are related to widespread in situ cancer and invasive bladder cancer, especially when the lesion is located in the bladder trigone area. Therefore, long-term 'cystitis' that cannot be cured should be vigilant about the possibility of bladder cancer, especially in situ cancer.

　　3. Symptoms of urinary tract obstruction:Large tumors, tumors at the bladder neck, and blood clots blocking can cause dysuria and even urinary retention. Tumor invasion of the ureteral orifice can cause upper urinary tract obstruction, leading to lumbar pain, renal hydrops, and renal dysfunction.

　　Bladder cancer should be treated in a timely manner, otherwise, it may worsen and cause a lot of harm to patients. The prevention of bladder cancer is very important. Avoiding contact with bladder carcinogens can effectively prevent the occurrence of the disease. The specific preventive measures are as follows.

　　1. Workers who come into contact with chemical drugs and radioactive substances should strengthen labor protection and undergo regular physical examinations.

　　2. After bladder cancer surgery or radiotherapy, a review should be conducted every 3 months, and traditional Chinese medicine for strengthening the body should be continued.

　　3. Try to avoid unnecessary radiation examinations and contact with chemicals such as arsenic, mercury, and cyanides.

　　4. Strengthen the publicity of cancer prevention knowledge, popularize cancer prevention knowledge, and strive to achieve early diagnosis and early treatment.

　　5. Take an active approach to physical exercise to improve immune function.

　　6. Eat a diet rich in vitamin-containing foods, ensure the intake of nutritious foods, and eat less spicy and greasy foods.

　　7. Quit smoking and drinking. Pay attention to careful living and avoiding overindulgence in sexual activity during the treatment and recovery period. Women of childbearing age should practice contraception. Moderate exercise should be done to avoid fatigue.

　　8. Use alkylating agents and certain immunomodulatory agents with caution, strictly control their indications, dosage, and course of treatment.

　　When bladder cancer patients visit the doctor, some doctors may perform rectal examination, and for female patients, a pelvic examination is also required to determine whether the bladder tumor can be palpated and whether it invades outside the bladder. Other common examinations are as follows.

　　1. Urinary sediment cytology or other urine screening.

　　2. Abdominal flat film and intravenous urography examination.

　　3. Cystoscopy, direct examination of the internal condition of the bladder, while the doctor may also perform a biopsy, that is, to take several pieces of tissue suspected to be tumor. The biopsy specimens will be sent to the pathologists, who will diagnose the type and depth of invasion of the tumor under the microscope. Further examinations and treatments will be determined according to the biopsy results.

　　4. Regardless of the biopsy results, each patient must undergo an X-ray examination of the upper urinary tract, that is, an abdominal flat film and intravenous urography examination, to confirm that there is no tumor in the kidneys and ureters, as these parts cannot be seen under cystoscopy.

　　5. Tumor marker determination.

　　Bladder cancer patients should eat foods rich in vitamins, high-quality protein, and light, nourishing foods. It is forbidden to eat spicy, stimulating, greasy, and high-cholesterol foods. Chemotherapy and radiotherapy cause many bladder cancer patients to suffer from both physical and mental injuries, greatly affecting their normal lives. There are many things that need to be understood during the treatment of bladder cancer, especially the diet during chemotherapy. The specific dietary precautions are as follows.

　　1. During bladder cancer chemotherapy, the diet should be light and nutritious. If symptoms such as vomiting, nausea, diarrhea, and decreased appetite occur during chemotherapy, the food intake of most patients is relatively small. Therefore, food should be rich in high-quality protein and high-calorie foods, and it is necessary to continue eating. When the patient's food intake is insufficient, intravenous injection of glucose and protein can be used.

　　2. Provide patients with foods rich in vitamin A and vitamin C. Studies have shown that vitamin C can strengthen the function of the intercellular matrix, which is the first barrier to prevent the spread and formation of cancer cells. It can enhance resistance and inhibit the growth of cancer cells.

　　3. Eat small and frequent meals. Patients can appropriately increase some small-calorie, high-nutrition foods, such as bread, chocolate, and egg products, outside of the three main meals. Pay attention to avoid the peak period of chemotherapy drug action when eating. If it is intravenous chemotherapy, it is best to eat on an empty stomach.

　　The main treatment method for bladder cancer is surgery, and the treatment methods are described as follows.

　　1. Surgical operation is the main method for treating localized bladder cancer. Superficial (non-muscle invasive) bladder cancer is primarily treated with transurethral resection of bladder tumor (TURBT), and different intravesical chemotherapy or immunotherapy regimens are adopted after surgery according to the specific tumor stage and pathological grade. For muscle invasive bladder cancer, radical cystectomy is the first choice, and systemic chemotherapy can be selectively adopted before and after surgery to improve the efficacy.

　　2. For some patients with invasive bladder cancer who cannot undergo radical surgery or have a desire to retain the bladder, an integrated treatment plan for retaining the bladder can be adopted, including endoscopic surgery, radiotherapy, and systemic chemotherapy. For metastatic bladder cancer (including lymph node metastasis), systemic chemotherapy is the only method that can extend the patient's survival. Surgery, radiotherapy, or arterial intervention therapy only have palliative effects such as hemostasis and pain relief to improve the patient's quality of life.

　　3. Transurethral resection of bladder tumor (TURBT) is a minimally invasive surgery with no incision on the body surface, and the patient recovers quickly after surgery. It requires a special cystoscope that can remove bladder tumors, known as an electroresectoscope. The insertion route is the same as that of a cystoscope, entering through the urethral orifice. The scope has an electroresecting loop that can extend and retract forward and backward. When electricity passes through, the electroresecting loop can cut tissue and also cauterize tissue to stop bleeding. After the electroresecting loop is withdrawn, the tissue fragments can be flushed out of the bladder. Then, these tissues are sent to the pathological department doctor, who determines under a microscope whether they are cancerous. The pathological department doctor usually needs several days to examine these tissues.