Purified protein derivative skin test prior to bacillus Calmette-Guérin therapy enhances the clinical efficacy of BCG therapy in patients with non-muscle invasive bladder cancer
Little is known about the clinical impact of the purified protein derivative (PPD) skin test prior to BCG therapy in patients with non-muscle invasive bladder cancer (NMIBC) treated with adjuvant BCG therapy.
A total of 498 NMIBC patients initially treated with adjuvant BCG therapy at our institute between 1990 and 2015 were included. Of them, 320 (64.3%) had received the PPD skin test prior to BCG therapy (PPD group), while 178 (35.7%) patients had not (non-PPD group). The PPD skin test was performed 1 to 2 weeks prior to the start of adjuvant BCG therapy. We evaluated the association between PPD skin test performed or not performed and clinical outcomes including oncological outcomes and the incidence of BCG-related side effects in NMIBC patients treated with BCG therapy.
Patients in the PPD group had a significantly higher incidence of pT1 (40.6%) and lower incidence of concomitant CIS (16.9%) as compared to those in the non-PPD group (28.1% and 24.2%, respectively). The 5-year recurrence-free survival (RFS) rate of patients in the PPD group was 66.6±2.8%, which was significantly higher than that in their counterparts (59.1±4.1%, p=0.048, Figure). Univariate Cox regression analysis revealed that tumor multiplicity (p=0.002), the presence of concomitant CIS (p=0.042), and receiving the PPD skin test (p=0.048) were associated with tumor recurrence. Multivariate Cox regression analysis revealed that tumor multiplicity (hazard ratio [HR] of 1.886, p=0.002), recurrent tumor (HR of 1.589, p=0.017), and receiving the PPD skin test (HR of 0.720, p=0.038) were independently associated with tumor recurrence. There was no significant difference in progression-free survival between the PPD group and non-PPD group (p=0.753). The rate of any BCG-related side effects in the PPD group was 56.6%, which was significantly higher than that in the non-PPD group (36.5%, p<0.001). Furthermore, the incidence of the major side effect of LUTS in the PPD group was 9.1%, which was significantly higher than that in the non-PPD group (3.9%, p=0.034). </p>
The PPD skin test prior to BCG therapy may enhance immune responses to BCG, leading to improvements in the clinical outcomes of BCG therapy in NMIBC patients.