Benefits

Clinical clearance in the 5-FU group was superior to the interferon alfa-2b group (100% versus 90%) at 8-week assessment. A statistically significant difference in histological response to treatment was further noted at 4 and 8 weeks in favour of interferon (P<0-05).78 This trial failed to specify the number of BD lesions in each treatment group; consequently, the reported data prevents conclusions for BD independent of AK.

In the uncontrolled trials, clinical clearance rates were generally high, ranging from 87%80 to 100%.49 It is noteworthy that, of studies with sufficient follow up to document recurrence (12-24 months), one study reported a significantly higher recurrence rate (20%)81 than other studies (0% and 8%).49 5880 The largest uncontrolled trial (n = 41) used 5-FU (in 1-3% in propylene glycol) applied twice daily for 2-3 months.58 Clinical clearance rate in this study was 93%, with an 8% recurrence rate during a median follow up of 8 years (range: 6-121 months). The authors suggest that at least 2-5% 5-FU in propylene glycol is required for extrafacial sites.

The base in which 5-FU is delivered significantly affects its activity: 20% 5-FU in an ointment base, 5% 5-FU in a cream base, and 1% 5-FU in propylene glycol provide approximately equivalent cytotoxic activity.72,77,82,83 Several studies investigated ways to enhance 5-FU activity. Iontophoresis does not appear to improve 5-FU activity when compared with 5-FU alone.49,58,80,81 Application under occlusion, pretreatment with keratolytic agents, or deliberate exposure to sunlight (photosensitivity effect of 5-FU) are anecdotally reported as enhancement techniques.58

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