The efficacy and suitability of
photodynamic therapy (
PDT) was compared with that of
cryotherapy in the treatment of 40 lesions of
Bowen's disease. Lesions were randomized to receive either
cryotherapy with liquid
nitrogen, or
PDT using a portable desktop lamp incorporating
a 300 W
xenon short
arc discharge source. A
porphyrin precursor, 5-aminolaevulinic
acid (5-ALA), was applied topically 4 h before irradiation in the
PDT group. Each lesion received 125 J/cm2 at a fluence rate of 70 mW/cm2. All patients were reviewed at 2-monthly intervals and treatments repeated if required.
Cryotherapy produced clearance in 10 of 20 lesions after one treatment, the remaining 10 lesions requiring two or three treatment applications.
PDT resulted in clearance of 15 of 20 lesions after one treatment and of the remaining five lesions after a second treatment. The probability that a lesion cleared after one treatment was greater with
PDT than
cryotherapy (P < 0.01).
Cryotherapy was associated with ulceration (five of 20),
infection (two of 20) and recurrent disease (two of 20); no such complications occurred following
PDT.
PDT using a non-
laser light source and topical 5-ALA appears to be at least as effective as
cryotherapy in the treatment of
Bowen's disease with fewer adverse effects.