Urinary interleukin-2 monitoring during prolonged bacillus Calmette-Guerintreatment: Can it predict the optimal number of instillations?

Purpose: In patients with superficial bladder cancer treated with a first B -week instillation course of bacillus Calmette-Guerin (BCG) the induction p attern of urinary interleukin (IL)-2 has been described, and the levels of urinary IL-2 were associated with the clinical response to BCG treatment. W e evaluated urinary IL-2 kinetics in patients with recurrent superficial bl adder tumor receiving a second or third 6-week BCG instillation course. To our knowledge there have been no studies of prolonged BCG treatment and uri nary cytokine responses. Materials and Methods: Urinary IL-2 was determined in 12 patients with supe rficial transitional cell carcinoma of the bladder receiving a complete (6- week) second or third BCG instillation course and in 3 patients receiving 3 BCG instillations during a maintenance schedule at month 3. Urinary IL-2 w as determined with an enzyme-linked immunosorbent assay using an oligoclona l system. Results: Of 12 patients 10 had a urinary IL-2 positive response during the subsequent BCG course and at week 1 urinary IL-2 was already increased. Com paring the urinary IL-2 kinetics observed during a second or third with a f irst course, urinary IL-2 tended to be higher during the first and lower du ring the last weeks. If the interval between subsequent courses was short ( 12 months or less) significantly higher urinary IL-2 levels at weeks 1 and 2, and a fewer level at week 6 were observed. Conclusions: During a repeat BCG instillation course urinary IL-2 reached a maximum at an earlier week, especially if the interval between the subsequ ent courses was short. Since an association between urinary IL-2 levels and response to BCG treatment during an induction course has been observed, th ese immunological data argue in favor of a Limited number of instillations during prolonged BCG therapy which could reduce side effects as well as cos ts.