Bladder adenocarcinoma

　　One, etiology of the disease

　　It has been confirmed that chemical carcinogens can induce bladder cancer, but there are also many bladder cancer patients without a history of exposure to chemical carcinogens. The current more common view is that viruses or certain chemical carcinogens act on the proto-oncogenes in the human body, causing them to be activated into oncogenes. It is related to the following factors:

　　1. Workers who have long-term contact with aromatic substances, such as dye, leather, rubber, and painters, have an increased incidence of bladder cancer. Before 1954, some scholars made statistics. In workers exposed to aniline, the incidence of bladder cancer was 30 times higher than that of the general population. Benzidine, 4,4-diaminobiphenyl, 4-aminobiphenyl, β-naphthylamine, and other substances are considered to be certain exogenous chemical carcinogens. These substances enter the body, are metabolized by the liver, excreted into the bladder by the kidneys, and then decomposed into α-aminonaphthalene by β-glucuronidase (β-glucuronidase), which has carcinogenic effects, leading to occupational bladder cancer. The latent period of these substances is relatively long, reaching about 20 years.

　　2. Smoking is also a cause of increased incidence of bladder cancer. Recent studies have shown that the metabolism of carcinogenic tryptophan in the urine of smokers increases by 50%, and the level of tryptophan returns to normal when smoking is stopped. Rose and Walleace (1973) studied the chemical composition of the urine of bladder cancer patients in two groups: smokers and non-smokers, and found a higher level of tryptophan in smokers, while non-smokers had a lower level. They also found that vitamin C can reduce the activity of tryptophan in both smokers and non-smokers.

　　3. Abnormal metabolism of tryptophan in the body. Abnormal metabolism of kynurenine can produce some metabolites, such as 3-hydroxy-2-aminoacetophenone, 3-hydroxy-anthrenilic acid, which can directly affect the synthesis of DNA and RNA in cells. These metabolites are excreted into the bladder after being metabolized by the liver and excreted by the kidney. After being acted upon by β-glucuronidase, they have carcinogenic effects. Often, these carcinogens are found in significantly higher concentrations in the urine of patients with bladder tumors.

　　4. Long-term local stimulation of the bladder mucosa, such as long-term chronic infection, long-term stimulation of bladder stones, and urinary tract obstruction, may be a factor that induces tumors. Adenocystitis and mucosal leukoplakia are considered as precancerous lesions.

　　5. Drugs. In recent years, the use of drugs that can cause bladder cancer has also attracted attention, such as the use of large amounts of phenacetin (phenacetine)类药物, which has been confirmed to cause bladder cancer.

　　6. Parasitic diseases. In severe Schistosomiasis haematobium patients, the incidence of bladder cancer is quite high.

　　7. Human papillomavirus DNA may bind to DNA fragments of certain genes that regulate apoptosis, interfere with the transmission, transcription, and replication of these gene information, and regulate cell cycle at multiple stages, thereby exerting its carcinogenic effect.

　　8. The occurrence of bladder cancer is also related to racial and environmental factors.

　　Second, pathogenesis

　　Adenocarcinoma accounts for less than 2% of primary bladder cancer and is divided into 3 types: primary bladder adenocarcinoma, urachal carcinoma, and metastatic adenocarcinoma. Adenocarcinoma can also occur in the intestinal tract substitute for the urethra, bladder expansion, etc. Primary bladder adenocarcinoma is most common at the bottom of the bladder (trigone, neck, lateral wall), and the top of the bladder. The incidence of adenocarcinoma is highest in bladder exstrophy. The histological types of intestinal adenocarcinoma, such as signet ring cell carcinoma and colloid carcinoma, can also occur in the bladder. Adenocarcinoma may be papillary or solid. Most adenocarcinomas have poor differentiation and infiltration. Urachal carcinoma is extremely rare and usually originates from the bladder wall and invades the bladder. Urachal carcinoma can spread to the perivesical space. Bloodstained or mucoid secretions or mucoid cysts may appear at the umbilicus, and if the bladder lumen is involved, mucous may appear in the urine. Metastatic adenocarcinoma mainly originates from the rectum, stomach, breast, prostate, and ovary.

　　Cancer involving the ureteral orifice can cause occlusion, leading to hydronephrosis of the renal pelvis at the occlusion site. In severe cases, the significantly increased intracystic pressure can reduce the glomerular filtration rate, causing the excretion of creatinine and urea nitrogen to be blocked, and even leading to renal insufficiency. If infection is present, hematuria may worsen, and symptoms such as frequent urination, urgency, and fever may appear. Patients with persistent hematuria may also develop anemia due to blood loss.

　　1. The most common clinical symptom is gross hematuria, followed by urinary tract irritation symptoms, such as frequent urination, urgency, dysuria, and discomfort in the lower abdomen; some patients may have mucous urine of varying amounts. Thicker mucous urine may also block the urethra, causing urinary retention, which is one of the characteristics of bladder adenocarcinoma.

　　2. Adenocarcinoma originating from the urachus at the top of the bladder is often asymptomatic and hidden in location, but some patients may feel a mass in the lower abdomen. In the late stage, infiltration and metastasis symptoms may appear.

　　The diagnosis of bladder adenocarcinoma based on clinical manifestations and examination diagnosis is generally not difficult, but the diagnosis of early bladder adenocarcinoma is not easy. It is necessary to combine the characteristics of the medical history with relevant auxiliary examinations for comprehensive judgment, and strive for early diagnosis.

　　The prevention of bladder cancer has 5 aspects:

　　1. Take preventive measures based on the cause, such as confirming that among external carcinogenic factors, occupations such as dyes, rubber, and leather can cause the occurrence of bladder cancer. Smoking and taking certain drugs can significantly increase the incidence of bladder cancer. This requires improving the production conditions of industries such as dyes, rubber, and leather, advocating the prohibition of smoking, and avoiding the long-term and large-scale use of drugs that can cause bladder cancer.

　　2. Pay high attention to the close follow-up of patients with hematuria, especially for male patients over 40 years old with hematuria of unknown cause. In principle, strict and formal diagnostic examinations should be adopted, including cystoscopy, for the screening of bladder cancer.

　　3. Carry out mass screening work, especially for high-risk populations.

　　4. Strengthen basic and clinical research work, including improving the accuracy of non-invasive examinations for early diagnosis of bladder cancer and developing drugs to prevent the recurrence of bladder cancer.

　　5. Carry out education and publicity on tumors, popularize relevant medical knowledge, enhance the public's understanding of urinary system tumors, and encourage them to take regular physical examinations seriously, establish an early visitation awareness, which is conducive to early diagnosis of bladder tumors.

　　Urinary turbidity, increased amount of mucus, and mucus-like substances in urine, as well as necrotic desquamated material, can be detected for tumor cells, with a high positive rate.

　　1. CT scan shows a broad base of the tumor, a solid mass growing inward and outward along the bladder wall.

　　2. Cystoscopy shows primary adenocarcinoma most commonly in the bladder base, including the bladder trigone and adjacent lateral wall and bladder top, and can also occur at any part of the bladder. Bladder adenocarcinoma can present as papillary, polypoid, or nodular, and can also be flat, ulcerative, with soft tumor tissue and mucus, common bleeding and necrotic foci. Some cases may present as diffuse fibrosis leading to thickening of the muscular layer, resembling leather-like.

　　3. Bladder urography, especially filming in the head-down position, can not only detect bladder filling defects but may also see pressure marks of tumors outside the bladder, which is more common in urachal adenocarcinoma.

　　Increase intake of high-fiber foods and fresh vegetables and fruits, maintain a balanced diet, including proteins, sugars, fats, vitamins, trace elements, and dietary fibers, mix meat and vegetables, diversify food varieties, and give full play to the complementary effects of nutrients between foods.

　　First, Treatment

　　1. The treatment of choice for bladder adenocarcinoma is radical cystectomy with pelvic lymph node dissection, and transurethral resection of bladder tumor (TURBT) is generally not performed.

　　2. For small tumors limited to the top, side wall, and anterior wall of the bladder, partial cystectomy can be considered, with the margin of resection more than 3cm away from the tumor. Partial cystectomy can also be chosen for small, well-differentiated urachal adenocarcinoma.

　　3. Bladder adenocarcinoma is insensitive to radiotherapy and chemotherapy. Auxiliary therapy has certain efficacy.

　　Second, Prognosis

　　The prognosis is poor, with an approximate 5-year survival rate of 33%. The reasons are:

　　(1) The diagnosis was already at an advanced stage at the time of diagnosis.

　　(2) The tumor deeply infiltrates and metastasizes early.

　　(2) The malignancy of tumor cells is high and they are highly prone to metastasis.

　　(3) The preoperative diagnosis was not adenocarcinoma, resulting in incomplete resection of the tumor.

　　(4) Both chemotherapy and radiotherapy are insensitive.