Correlation between protoporphyrin IX fluorescence intensity, photobleaching, pain and clinical outcome of actinic keratosis treated by photodynamic therapy.

BACKGROUND

Photodynamic therapy (PDT) with Metvix® is a good therapeutic option to treat actinic keratosis, but it presents drawbacks (pain, lesion recurrences, heterogeneous outcome), emphasizing the possible need to individualize treatment.

OBJECTIVE

We assessed whether PDT clinical outcome and pain during treatment were correlated with protoporphyrin IX fluorescence intensity and photobleaching.

METHODS

25 patients were treated by Metvix PDT. The outcome was evaluated after 1.3 (±0.4), 7.6 (±1.8), 13.2 (±1.2) and 33.6 (±3.0) months. After administration of Metvix, red light (632 ± 10 nm) was delivered with a light-emitting diode panel device. The outcome was assessed on a cosmetoclinical scale.

RESULTS

All patients who showed a fluorescence level before PDT treatment above a certain threshold had a complete recovery at 33.6 (±3.0) months.

CONCLUSION

Our approach could be used to individualize PDT treatment based on the pretreatment fluorescence level, and to predict its long-term outcome.