Purpose
No reliable methods currently exist to predict patient response to intravesical immunotherapy with bacillus Calmette-Guérin (BCG), given after transurethral resection for high-risk non-muscle-invasive bladder cancer. We initiated a prospective clinical trial to determine whether fluorescence in situ hybridization (FISH) results during BCG immunotherapy can predict therapy failure.
Materials and Methods
Candidates for standard of care BCG were offered participation in a clinical trial. FISH was performed prior to BCG and at 6 weeks, 3 months, and 6 months during BCG therapy with maintenance. Cox proportional hazards regression was used to assess the relationship between FISH results and tumor recurrence or progression; the Kaplan-Meier product limit method was used to estimate recurrence- and progression-free survival.
Results
One hundred twenty-six patients participated. At a median follow-up of 24 months, 31% of patients had recurrent tumors and 14% experienced disease progression. Patients who had positive FISH results during BCG therapy were 3-5 times more likely than those who had negative FISH results to develop recurrent tumors and 5-13 times more likely to experience disease progression (p < 0.01). The timing of positive FISH results also affected outcome; for example, patients with a negative FISH result at baseline, 6 weeks, and 3 months demonstrated an 8.3% recurrence rate, compared to 48.1% in those with a positive FISH result at all three time points.
Conclusions
FISH results can identify patients who are at risk of tumor recurrence and progression during BCG immunotherapy. This information may be used to counsel patients about alternative treatment strategies.
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