After Zhang’s bladder cancer surgery, his doctor told him that the recurrence rate of bladder cancer after surgery is high, up to about 70%, and that regular intravesical instillation of BCG vaccine is needed to prevent tumor recurrence. But Zhang heard another patient say that he always had frequent, urgent and painful urination after each instillation, and sometimes he had fever. After hearing these words, Zhang was very worried and could not decide whether to instill BCG vaccine or not.
In China, bladder cancer is the most common malignant tumor in the urinary system. Transurethral electrocautery, electrodesiccation, laser treatment and open surgery are effective means of treating bladder cancer, but the high frequency of recurrence after treatment is frightening to patients and their families and has caused headaches to medical workers, for which a lot of studies have been conducted at home and abroad and some effective recurrence prevention measures have been summarized. BCG intravesical infusion is one of the effective methods.
BCG vaccine is a live strain of Mycobacterium bovis with reduced virulence after treatment, which can survive and reproduce and still has some pathogenicity. 1976 was the first time that BCG vaccine was used by American experts for the treatment of superficial bladder cancer and prevention of postoperative recurrence of bladder cancer. This treatment method, with its simple and effective features, has been widely used all over the world. Clinical applications in the past 30 years have shown its obvious efficacy, with an efficiency of over 60% in treating superficial bladder cancer and reducing the recurrence rate of bladder cancer to about 20%. BCG intravesical infusion is by far the most successful example of human immunotherapy for malignant tumors, but its side effects and complications cannot be ignored.
The most common reaction to BCG intravesical infusion is cystitis. About 95% of patients have varying degrees of urinary frequency, urgency and pain after infusion, which may be accompanied by hematuria, and some patients also have flu-like systemic symptoms: low fever (below 38.5°C), runny nose and general malaise. These systemic reactions are the body’s hypersensitivity reaction to BCG vaccine, not infection, and the symptoms mostly disappear on their own in 2 days without treatment. Many patients often take haloperidol or other anti-inflammatory drugs on their own after irrigation, hoping to eliminate the urinary tract irritation or systemic symptoms caused by cystitis, but this is actually unnecessary.
Patients with more severe reactions can be treated symptomatically with medications such as oral selenium and aspirin. However, if the symptoms persist for more than 2 days, or if the fever exceeds 38.5°C, or if the hematuria is severe, patients must be alert and should be promptly seen by a hospital. These patients often require anti-tuberculosis treatment with oral Remifentan 300 mg daily until the symptoms are relieved. In a few patients, BCG infusion can cause more serious complications, such as bladder contracture, leukopenia, testicular and epididymal tuberculosis, and pulmonary tuberculosis, which should be treated immediately at a hospital for regular treatment.
According to the observation of 200 patients who were infused with BCG after bladder cancer surgery in Cancer Hospital of Chinese Academy of Medical Sciences, the total incidence of serious complications was about 6%, which were all controlled after treatment. The occurrence of serious comorbidity is often related to the entry of BCG into the blood circulation, and the breakage and inflammation of the bladder and urethral mucosa both tend to make BCG enter the blood dissemination, therefore, patients with urinary tract infection should stop the instillation and perform BCG instillation at least 10 days after tumor electrosurgery or biopsy. Avoid rough handling during instillation and damage to urethral mucosa. The drug must be instilled into the bladder through the catheter. Individual doctors, for the sake of saving time or when some patients instill the drug by themselves, directly instill the drug through the urethral opening with a syringe, which is wrong and dangerous and often leads to posterior urethral abscess and ulceration, or even other serious complications.
BCG is more effective than chemotherapy drugs (such as mitomycin) in preventing recurrence of superficial bladder cancer, but also has more side effects than intravesical instillation of chemotherapy drugs; therefore, intravesical instillation of BCG is mainly used for bladder cancer patients with higher risk of recurrence or as a second-line drug after failure of chemotherapy drug treatment.