General characteristics of the disease
Bladder cancer originates from the lining of the urinary bladder and, like most malignant neoplasms, is strictly an epithelial tumor. According to ICD-10, the disease is coded as C67.
Histologically, several tumor types are distinguished:
- Transitional cell (urothelial) carcinoma — the most frequent histological variant;
- Squamous cell carcinoma — occurs significantly less often;
- Adenocarcinoma — the rarest variant.
Risk factors
The primary and most significant risk factor for bladder cancer development is smoking, including the use of electronic cigarettes, which do not differ from conventional cigarettes in terms of risk.
Additional risk factors include:
- Chronic cystitis — prolonged inflammation of the mucosa increases the risk of malignant transformation;
- Exposure to aromatic amines — an occupational hazard for paint and varnish production workers (specifically, exposure to aniline), which places such patients in a high-risk group.
Diagnostics and macroscopic presentation
A distinctive feature of bladder cancer is the possibility of diagnosis directly during an outpatient visit using cystoscopy. Upon cystoscopic examination, the tumor often has a characteristic appearance resembling cauliflower-like growths, and may also present as villous growths.
Staging
Bladder cancer staging is performed according to the TNM (Tumor, Nodus, Metastasis) system, although it has specific features compared to other oncological sites. In particular, the Ta stage may be designated — non-invasive papillary carcinoma that does not invade the lamina propria of the bladder mucosa, which is an atypical grading for the classical TNM system.
Intravesical therapy: BCG vaccine
For the treatment of bladder cancer, intravesical administration of the BCG vaccine is used, the mechanism of action of which is based on the formation of a local immune response helping the body fight tumor cells. The exact mechanism of this effect is not fully understood.
The use of BCG is associated with a number of organizational and clinical challenges:
- The vaccine is live, therefore its administration requires a dedicated infection control room and constant monitoring of medical staff and patients;
- There is a high risk of tuberculosis infection if the handling protocols for the drug are violated;
- Complications include various inflammatory reactions, including tuberculous nephritis and other adverse effects;
- Despite the fact that BCG is quite effective in reducing the recurrence rate and treating bladder cancer, due to the complexity of organizing the procedure, its use is limited; in particular, it is not widely used in most cancer centers, where intravesical chemotherapy is preferred.
Systemic drug therapy
Bladder cancer is considered one of the most challenging localizations for medical treatment, since most standard chemotherapy regimens are based on platinum-based drugs.
- Cisplatin exhibits marked nephrotoxicity and is contraindicated in patients with a low creatinine clearance, as it can lead to severe renal impairment;
- Carboplatin has a milder toxicity profile compared to cisplatin, but with a creatinine clearance of less than 30 mL/min, platinum-based regimens are not prescribed at all;
- Alternatives include immune checkpoint inhibitors — atezolizumab and pembrolizumab. According to clinical guidelines, in first-line therapy these drugs are used only in the presence of positive PD-L1 expression, which, according to clinical experience, occurs in less than 10% of patients;
- In second-line therapy (upon progression during other treatments), immunotherapy can be used regardless of PD-L1 status;
- In the absence of indications for combination regimens, monotherapy chemotherapy is possible (for example, with cabazitaxel or gemcitabine). Such treatment is predominantly palliative in nature and aims to improve the patient's quality of life rather than achieve a complete cure or significant tumor shrinkage.
Key points
- Bladder cancer is most commonly represented by transitional cell (urothelial) carcinoma, and less frequently by squamous cell carcinoma and adenocarcinoma.
- The main risk factor is smoking, including electronic cigarettes; additional factors are chronic cystitis and exposure to aromatic amines.
- Diagnosis is possible via cystoscopy during an outpatient visit; the tumor often looks like cauliflower-like growths.
- TNM staging has specific features, including the designation of the Ta stage.
- Intravesical BCG vaccine is effective, but requires a dedicated infection control room and carries the risk of tuberculous complications, limiting its use.
- Most chemotherapy regimens are based on platinum drugs, which are contraindicated in low creatinine clearance.
- Immunotherapy (atezolizumab, pembrolizumab) in the first line requires a positive PD-L1 status.
- If standard therapy is not feasible, palliative monochemotherapy is used to improve the patient's quality of life.