Pre-operative IL-2 immunoprophylaxis of cancer recurrence: long-term clinical results of a phase II study in radically operable colorectal cancer.

This study evaluates retrospectively the outcome of 20 colorectal cancer patients radically operated (M/F 13/7; primary/recurrent 15/5; Dukes B=11; C=6; D=3) who received pre-operative IL-2 (18,000,000 IU/daily s.c. for 3 days) and the outcome of 40 colorectal cancer (primary/recurrent 40/0) patients age, sex and stage-matched radically operated, as control group. After a median follow-up of 72 months, in the IL-2 pre-operative group we observed 6/20 recurrences (30%) vs. 19/40 (47.5%) in controls. Mean and median disease-free period in patients who relapsed were respectively 21 months and 20.5 months (range 6-36) in IL-2 group vs. 14.1 and 12 months in the control group (range 3-34). After a 5-year follow-up, 4/20 (20%) IL-2 treated patients were dead vs. 19/40 control patients (47.5%) (log-rank X 2 =3.7, p=0.05). Pre-operative IL-2 administration is safe, active in preventing post-operative lymphocytopenia and seems to improve the clinical outcome in radically operated colorectal cancer patients.