4545 Background: We investigated the association between purified protein derivative (PPD) skin test reaction prior to BCG therapy and clinical outcomes, both oncological outcomes and occurrence of side effects, in BCG-naïve non-muscle invasive bladder cancer (NMIBC) patients. Methods: A total of 288 NMIBC patients who received PPD skin test prior to BCG therapy were included. The PPD skin test reaction was categorized into three groups: positive, slightly positive, and negative. The presence of an induration was positive. If an induration was absent, an erythema 10 mm or more and less than 10 mm corresponds to slightly positive and negative, respectively. Results: Sixty-six (22.9%), 149 (51.7%), and 73 (25.3%) patients had positive, slightly positive, and negative PPD skin test results, respectively. The 5-year recurrence-free survival rate of patients with a positive PPD skin test was 89.4±4.1%, which was significantly higher than that of patients with slightly positive (65.5±4.2%, p = 0.001) and negative (56.4±6.6%, p < 0.001) results. Multivariate Cox regression analysis demonstrated that a positive PPD skin test was independently associated with tumor recurrence (Hazard ratio of 0.213, p < 0.001) but not with stage progression. The occurrence rate of major side effects in patients with a positive BCG skin test (33.3%) was significantly higher than that in patients with slightly positive (26.8%) and negative PPD skin tests (13.7%). The incidence rate of fever persisting beyond 2 days or fever of ≥38°C in patients with a positive PPD skin test (18.2%) was significantly higher than that in patients with slightly positive (8.7%) and negative PPD skin tests (4.1%). Conclusions: NMIBC patients with a positive PPD skin test and who were treated with BCG therapy had a significantly lower tumor recurrence rate and higher incidence of major side effects such as fever persisting beyond 2 days or fever of ≥38°C. Our findings suggest that PPD skin test prior to BCG therapy can predict clinical outcomes following BCG therapy and provide useful information regarding who would experience a strong therapeutic effect for BCG therapy and BCG-related major side effects.
