Background: This study was designed to investigate whether there is a correlation between interleukin (IL)-8 secretion rate and recurrences in induction bacillus Calmette-Guérin (BCG) immunotherapy following transurethral resection (TUR) in cases of primary non-muscle-invasive bladder cancer (NMIBC).
Patients and methods: A total of 41 patients with NMIBC were randomized to receive a 6-week course with a standard dose of 81 mg intravesical BCG. Voided urine samples were collected immediately before and after (at 2 and 4 hours) BCG instillation. IL-8 was measured using enzyme-linked immunosorbent assay. Patients were monitored according to European Association of Urology Guidelines.
Results: Patients were monitored for a mean duration of 21.0 +/- 13.86 months. The mean time to recurrence for the 15 patients who had recurrences was 11.2 months. After adjusting for risk factors, the change in IL-8 levels at 2 hours after the first BCG compared with the levels before BCG instillation was found to be significantly predictive of recurrence (P = .047), and the best cutoff point was estimated as 112 pg/mL. The sensitivity of this measure for prediction of recurrences was 53.3%, specificity was 88.5%, positive predictive value was 72.7%, and negative predictive value was 76.7%. Comparison of patients who had values below and above this cutoff point revealed that the recurrence-free survival rate was 76.7% versus 27.3%, and the expected recurrence-free survival time was 34.9 months versus 18.8 months (P = .006).
Conclusion: Besides numerous other prognostic factors that have been suggested so far, a cutoff point of 112 pg/mL for IL-8 levels measured 2 hours after the first BCG instillation appears to be a good predictive factor for successful outcome in BCG treatment following TUR.