Prolonged prophylaxis lowers recurrence risk.
BERLIN—Long-term prophylaxis with mitomycin C (MMC) significantly decreases the risk of tumor recurrence compared with short-term prophylaxis with MMC or bacillus Calmette-Guérin (BCG) in patients with non-muscle-invasive bladder cancer, according to German researchers.
The study, led by Martin G. Friedrich, MD, of the University of Hamburg, and his colleagues enrolled 627 patients with non-muscle-invasive bladder cancer (NMIBC). A total of 135 patients had low-risk tumors (Ta G1), and 63 were assigned to receive no adjuvant treatment (arm 1, controls) and 72 were assigned to receive six instillations with 20 mg MMC (arm 2).
A total of 492 patients had intermediate- to high-risk NMIBC (Ta G2-3 and T1 G1-3). Of these, 163 received BCG 2 x 108 CFU weekly for six weeks (arm 3), 176 received MMC 20 mg weekly for six weeks (arm 4), and 153 received MMC 20 mg weekly for six weeks followed by monthly instillations for three years (arm 5). Control cystoscopies were scheduled every three months until histologically confirmed tumor recurrence or until patients were followed for a maximum three years.
In the low-risk patients, three-year recurrence-free rates were 73% in arm 2 compared with 63% in arm 1 (controls), the researchers reported here at the 22nd European Association of Urology Congress. In the intermediate- and high-risk patients, the rates were 65.8% for arm 3, 68.9% for arm 4, and 86.1% for arm 5.
Adverse effects did not differ among the regimens, except for fever, which was more common in the BCG group.
“Patients with a pTa G1 tumors who received adjuvant treatment had a considerably lower recurrence rate than controls,” the authors concluded. “Long-term MMC significantly reduces the risk of tumor recurrence without enhanced toxicity compared to both short-term BCG and MMC in patients with inter-mediate and high risk NMIBC.”