Treatment of superficial bladder tumors: achievements and needs. The EORTC Genitourinary Group

The therapeutic objectives in the initial treatment of superficial tumors are to remove completely the tumor, to assess the need for further therapy and to plan the follow-up.

The EORTC Genitourinary Group assessed the percentage of patients with recurrence at 3 months (3RR) after complete resection of all visible lesions taking into account the institution, the number of tumors at presentation and the year of treatment. The 3RR was considered for 18 institutions. For single tumors, the 3RR varied from 0 to 36% and for multiple tumors from 7 to 75%. The 3RR by number of tumors was 8.7% for single tumors, 21% for 2-5 tumors and 32.2% for >5 tumors. The 3RR by year of entry for single tumors ranged from 21.0 to 43.8% during 1975-1978, from 6.3 to 12.7% during 1984-1986 and from 3 to 5.3% during 1987-1989. For multiple tumors it ranged from 50.0 to 61.5% during 1975-1978, from 20.2 to 27.3% during 1979-1983 and from 14.4 to 24.6% during 1984- 1986. The use of more refined instruments probably led to the decreasing percentage of the 3RR in more recent years, the large variation between institutions remains unexplained. The bladder's unique location renders its mucosa accessible to instillation of chemotherapeutic and immunotherapeutic agents. Cytostatics can be instilled into the bladder hours after surgery without severe complications. A single early instillation within 6 h after transurethral resection (TUR) in patients with a solitary bladder tumor category T(a)/T(1)G(1) to G(3) could reduce the recurrence rate per year by nearly 50%. The superiority of any of the commonly used intravesical drugs has never been demonstrated; the time to initiate therapy is important for treatment outcome. Optimal results can be achieved by initiating treatment early (within 24 h after TUR) and for a duration of 6 months, and maintenance (>6 months) for patients with a delayed first instillation (>7 days after TUR). Bacillus Calmette-Guérin (BCG) immunotherapy has been confirmed to be highly effective in the reduction of tumor recurrence, the treatment of residual papillary transitional cell carcinoma and the treatment of carcinoma in situ (CIS). The response rate in the treatment of the papillary disease averages 55%, and for CIS 73%. In the prevention of tumor recurrence the relative benefit of BCG is 45%. A direct prospective randomized comparison of BCG with intravesical chemotherapy has found it to be significantly superior to thiotepa, to doxorubicin and to mitomycin C when only patients with intermediate and high risk for recurrence were treated. In studies including patients with low recurrence risk, no advantage for BCG was found. Clinical trials showed no superiority of BCG immunotherapy to chemotherapy in preventing progression to > or =T(2).

Investigation of the concept of chemoimmunotherapy up to now lacked evidence of advantages for this approach. Preventive regulatory measures directed to decrease tobacco smoking and some occupational exposures to aromatic amines may contribute to the reduction of bladder cancer. Bladder cancer is a multistep process making this tumor a candidate for chemoprevention. To date, retinoids are the best-studied chemopreventive agents achieving mixed clinical results in superficial bladder tumors. The potent apoptosis-inducing retinoid fenretinide is currently in the phase III trials. The follow-up of patients with all types of superficial tumors must be lifelong; unfortunately cystoscopy cannot be replaced yet by the control of any markers present or not in the urine. There is hope this may change in the near future.