Efficacy of escalating doses of intravesical interferon alpha-2b in reducing recurrence rate and progression in superficial transitional cell carcinoma

Objective To compare the efficacy of three different doses of intravesical interferon alpha-2b (IFN alpha-2b) in reducing recurrence and progression r ates in superficial grade II, transitional cell carcinoma (TCC). Patients and methods Eighty-nine patients with primary or recurrent TCC sta ge Ta/T1, grade II, were randomly allocated into four groups after transure thral resection (TUR) of the tumour. Group A (20 patients) received no furt her treatment, serving as the control group; group B (22 patients) received 40 MU of IFN alpha-2b, group C (24 patients) 60 MU and group D (23 patient s) 80 MU. The instillations started within 48-72 h after TUR and were perfo rmed weekly for 2 months, bimonthly for the next 4 months and thereafter mo nthly for 6 months, The patients were followed for 36 months. The four grou ps were compared for the number of recurrences (simple recurrence rate), pr ogression in stage, disease-free interval and recurrence rate per 100 patie nt-months, Results During the follow-up, 33 patients had recurrence (13, eight, seven and five in groups A to D, respectively), The simple recurrence rate was 65 % for group A, compared with 36% (P = 0.06), 29% (P < 0.05) and 22% (P < 0. 01) for groups B, C and D, respectively. The differences in simple recurren ce rates between the groups treated with IFN alpha-2b were not statisticall y significant, Eleven patients experienced progression in stage, with six, three, one and one in groups A to D, respectively, The differences were sta tistically significant only between groups A and C (P < 0.05) and groups A and D (P < 0.05). The disease-free interval was lj months for group A, comp ared with 21.4 (P < 0.05), 26.1 (P < 0.001) and 30 months (P < 0.001) for g roups C to D, respectively. The disease-free intervals of the groups treate d with IFN alpha-2b were significantly different between all patients in gr oups B and D (P < 0.01) and only for those with stage T1 between groups C a nd D (P < 0.01), Finally the recurrence rate per 100 patient-months was 2.9 1, 1.19, 0.88 and 0.63 for groups A to D, respectively (all P < 0.001). The results were always in favour of the patients treated with the high dose, the only exception being the difference between groups C and D (P = 0.026), No side-effects of the drug were noted, nor was any adverse reaction repor ted from any patient, Conclusion These results show a significant advantage for adjuvant intraves ical IFN alpha-2b treatment over TUR alone for the 36 months of follow up a nd indicate that IFN alpha-2b can modify the clinical course of superficial TCC at least in the short term. The appropriate dose was apparently 80 MU, for although 40 MU was better than TUR alone, it was less effective than 6 0 MU and 80 MU; the SO MU dose was slightly better than 60 MU and thus this regimen is recommended.