We evaluate the predictive value of urinary cytokine levels of interleukin (IL) 8 and 18 for response in patients receiving intravesical bacillus Calmette-Guerin (BCG) for prevention of recurrences of superficial bladder cancer and treatment of carcinoma in situ.

In 28 patients with superficial bladder cancer treated with BCG IL-8 expression in the urine during the first 6 hours after the first BCG instillation was determined. In 17 patients IL-18 levels were also evaluated during the first 12 hours after BCG instillation. IL-8 and 18 levels were determined by solid phase double ligand enzyme-linked immunosorbent assay.

In 12 of the 28 patients assessed for IL-8 expression disease recurred after a median followup of 66 months. Median IL-8 expression during the first 6 hours for these patients was 851 ng. (range 232 to 8,497). Median IL-8 expression during the first 6 hours in patients without recurrence was 4,200 ng. (range 432 to 12,232). Of 8 patients with a followup of greater than 36 months 7 (88%) had no recurrent disease and IL-8 levels greater than 4,000 ng. Patients secreting more than 4,000 ng. IL-8 into the urine after BCG have a significantly higher chance of remaining disease-free (p <0.05), and those with elevated IL-18 expression have a significantly longer disease-free survival (p <0.05). After a median followup of 23 months (range 7 to 93) 6 of the 17 patients assessed for IL-18 expression had treatment failure. Median IL-18 expression in those patients during the first 12 hours was 2,632 pg. (range 860 to 8,298). Median IL-18 expression during the first 12 hours in patients without recurrence was 12,258 pg. (range 1,727 to 151,495).

In this study we confirmed the value of quantitative IL-8 expression in the urine during the first 6 hours after BCG instillation for superficial bladder cancer to predict freedom of disease. Furthermore, to our knowledge we report for the first time the potential value of IL-18 expression in the urine during the first 12 hours after BCG to predict freedom from disease. These findings may help improve the treatment of patients with superficial bladder cancer, especially by identifying those with a high risk of disease recurrence and progression after BCG therapy.