Increased protoporphyrin IX accumulation does not improve the effect of photodynamic therapy for actinic keratosis: a randomized controlled trial

Keratolytics can replace curettage in daylight photodynamic therapy for actinic keratosis on the face/scalp: A randomized clinical trial

BACKGROUND

Methyl aminolevulinate (MAL) photodynamic therapy (PDT) is commonly used for field treatment of actinic keratoses (AKs). In standard natural daylight PDT (n-DL-PDT) the first step, after the application of chemical solar filter, is removal of crusts and scales by curettage, followed by the application of MAL cream. Some patients experience intense pain during curettage and stinging after application of the photosensitizer to just curettaged skin.

OBJECTIVES

To evaluate whether n-DL-PDT without curettage, but preceded by application of keratolytics, would maintain a similar efficacy, based on clinical, dermoscopic, reflectance confocal microscopy (RCM) assessments, safety and patient satisfaction as standard n-DL-PDT with curettage.

METHODS

Forty patients with multiple AKs on the face and/or scalp were enrolled in this study. Patients were randomized into two groups of treatment as follows: (i) MAL n-DL-PDT without previous curettage, preceded by skin preparation at home with keratolytics (30% urea cream, twice a day for 7 days; -Cur group) and (ii) MAL n-DL-PDT preceded by skin preparation at the hospital with curettage (+Cur group).

RESULTS

Thirty-nine participants completed the study. Four hundred and twenty-one AKs in -Cur group and 337 AKs in +Cur group were treated. The mean reduction in the number of AK lesions 3 months after the treatment was 10.7 (-54.7%) in the -Cur and 10.4 (-58.7%) in the +Cur group. We found that the differences in terms of efficacy and patient satisfaction comparing the two treatment regimens were not statistically significant. The pain score reported during and after daylight exposure was similar and low in both groups. Moreover, no unexpected adverse events occurred during the trial period.

CONCLUSIONS

According to our results, curettage is not necessary to obtain the full treatment effect of n-DL-PDT. We experienced in a real-life setting that n-DL-PDT protocol could be changed by replacing curettage with keratolytics.

Methyl Aminolaevulinic Acid versus Aminolaevulinic Acid Photodynamic Therapy of Actinic Keratosis with Low Doses of Red-Light LED Illumination: Results of Long-Term Follow-Up

Photodynamic therapy (PDT) treatment for multiple actinic keratosis (AK) has been found effective when lower doses of red light were used with methyl aminolaevulinic acid (MAL). The aim of this study was to compare the results of lower doses of red light conventional PDT (h-PDT, 16 J/cm2) with MAL and aminolaevulinic acid (ALA) in a long-term follow-up. Patients with more than five symmetrical AK on the scalp who were candidates for PDT were selected and divided randomly between MAL and ALA treatment and patients were followed at 3 and 12 months. The responses were assessed by counting the total AK and the AK per patient. Pain and adverse events were also compiled. A total of 46 patients were treated, 24 with MAL, and 22 with ALA. The two groups were comparable at baseline (p > 0.005). No significant differences were found in the results of both treatments at 12 months, despite ALA exhibiting slightly better results at 3 months. No differences in pain and adverse events were assessed. Both ALA and MAL were effective when lower doses of red light were used in c-PDT. Long term efficacy was also documented. Further studies are necessary to determine the inferior point of red-light illumination without losing efficacy.

5-ALA loaded self-adhesive patch-PDT is effective and safe in the treatment of actinic keratoses on hands and arms

Photodynamic therapy (PDT) with 5-aminolevulinic acid hydrochloride (ALA) is an established method for the management of AK. PD P 506 A (brand name Alacare®) is an approved medicinal product for the treatment of AK located on scalp and face. It is a self-adhesive, light-proof patch loaded with 5-ALA HCl and was developed for easy handling. AK located on arms, hands or trunk do not respond as well to ALA-PDT as AK lesions on the head do. It has been reported that occlusion during ALA incubation can improve clinical outcome after ALA-PDT for AK on hands and arms. We present the results of a first explorative pilot study involving 20 participants with a total of 145 treated (122 evaluable) AK lesions. The trial investigated the conduct of two ALA-PDTs within 1-2 weeks and involved all severity grades of AK. The model-based percentage of complete clearance on lesion-basis was estimated being 78.0% (95%-CI: [64.6%, 87.3%]), and the by-participant calculation (patient-based clearance) led to similar results (78.7% with a 95%-CI of [67.0%, 90.3%]). The treatment was well tolerated. Local reactions during ALA patch incubation were rare whereas nearly all patients showed the expected reactions during or after the illumination, primarily erythema and pain. The study results indicate that two PD P 506 A-PDT sessions 1-2 weeks apart are an efficacious treatment for AK on hands and arms. Especially mild but also moderate lesions responded very well to PDT treatment involving ALA incubation under occlusion.

Fluorescence and thermal imaging of non-melanoma skin cancers before and during photodynamic therapy

BACKGROUND

Photodynamic therapy (PDT) has been shown to be less effective on the extremities. Protoporphyrin-IX (PpIX) fluorescence and skin surface temperature are variables that have been implicated in the differences in efficacy with body site, but objective studies have not been undertaken.

OBJECTIVES

To further investigate observations from our previous study that temperature and fluorescence during pro-drug incubation are correlated, through a prospective objective investigation of the relationships between fluorescence and skin surface temperature before and during PDT and relationships with body site and efficacy.

METHODS

Eighteen patients with Bowen's disease or basal cell carcinoma, who had been referred for PDT, were recruited to this study. PpIX fluorescence and thermal measurements were recorded at intervals during the pro-drug incubation and irradiation phases of PDT. Pain immediately after irradiation, and outcome at 3- and 12-months were recorded.

RESULTS

Temperature and PpIX fluorescence were higher on the trunk than lower leg immediately before treatment (median temperature 32.7 °C vs. 27.8 °C, p < 0.05 and median fluorescence 16.5 vs. 6.7, p < 0.05). Higher pain levels were reported during PDT on the extremities (median 5.7 vs. 2.2, p < 0.05). Clearance rates at 12-months were 80 %.

CONCLUSIONS

The study supports a correlation between temperature and PpIX fluorescence during PDT, providing robust objective data to support our previous hypothesis and observations. The higher pain levels, lower PpIX fluorescence on the lower leg, and the high efficacy rates at all body sites irrespective of temperature and fluorescence indicates that relationships between PDT treatment conditions and parameters is likely to be multifactorial.

Actinic keratoses contiguous with squamous cell carcinomas are mostly non-hyperkeratotic and with severe dysplasia

AIMS

Actinic keratosis (AK) is a precursor of cutaneous squamous cell carcinoma (SCC). No validated parameters can predict which AKs will progress into SCCs, but especially thick AKs are under suspicion. The clinical and histopathological thickness of AKs is strongly correlated. This study aimed to investigate the thicknesses and degree of dysplasia of AKs contiguous with SCCs assuming these AKs represent the AKs that have undergone malignant transformation.

METHODS

Files of the Pathology Department, Hospital of Southern Jutland, Denmark, were reviewed. 111 cases met the inclusion criteria: a skin biopsy containing an invasive SCC. All SCCs merged with an AK at the edge. Degree of dysplasia, epidermal thickness and stratum corneum thicknesses of AKs were measured.

RESULTS

All AKs showed severe dysplasia. Most AKs had a stratum corneum thickness under 0.1 mm and an epidermal thickness under 0.5 mm, corresponding to clinically thin and non-hyperkeratotic AKs.

CONCLUSIONS

Our result suggests malignant progression potential of AKs regardless of thickness.

How Much Protoporphyrin IX Must Be Activated to Obtain Full Efficacy of Methyl Aminolevulinate Photodynamic Therapy? Implication for Treatment Modifications

Photodynamic therapy (PDT) with methyl aminolevulinate (MAL) is a popular treatment for actinic keratoses (AK), and several PDT treatment modalities with similar cure rates are in use. The effect relies on the activation of protoporphyrin IX (PpIX) in premalignant cells. This study aimed to measure PpIX during each treatment modality to determine the minimal PpIX activation and shortest exposure time for optimal cure rate. In four different treatment modalities, we established the PpIX formation up to three hours after MAL application without illumination and measured the speed of PpIX photoactivation during 9 min of red light (37 J/cm²). The level of PpIX three hours after MAL application was set to 100 PpIX units. In comparison, 85 PpIX units were formed during daylight PDT, 57 PpIX units during pulse PDT, and 52 PpIX units without any curettage prior to MAL. The activation of 50 PpIX units should, therefore, be enough to obtain a full effect on AK. Further, red light illumination may be shortened from 9 min to 1–2 min. The results indicate that PDT can be performed successfully with half the illumination time used in daylight PDT today and with one fourth of the illumination time used in classical PDT.

Split-face study comparing conventional MAL photodynamic therapy in multiple actinic keratosis with complete time vs. half-time red light LED conventional illumination

BACKGROUND

Conventional photodynamic therapy (PDT) with methylaminolevulinic acid (MAL) and daylight PDT have demonstrated similar efficacy in the treatment of actinic keratosis (AK). The reason for the use of daylight is to reduce pain during illumination but daylight has the limitation of the weather conditions. The difference in the doses of red light applied between these two methods suggests that an intermediate dose with red light conventional illumination could be effective in PDT of AK.

OBJECTIVE

To compare the efficiency of conventional MAL-PDT with half-time conventional red light illumination in patients with multiple AK.

MATERIAL AND METHODS

Adult patients with more than five symmetrically distributed AK were selected. After randomization, one area was treated with conventional PDT (Aktilite^® , 630 nm, 37 J/cm² , 8 min), while the contralateral was illuminated half time (Aktilite^® , 630 nm, 37 J/cm² , 4 min). Patients evaluated pain in each different side. Patients were evaluated at baseline, 3 and 6 months after PDT treatment by a blinded dermatologist. A questionnaire to be done at home 24 h after completing treatment was deliver to the patients to evaluate any side-effects.

RESULTS

A total of 774 lesions were treated, 385 with conventional PDT and 389 with half-time PDT (P > 0.05). Conventional PDT was 85% of complete response of AK (327/385) at 3 months, and half-time PDT was 82% (319/389). At 6 months, conventional PDT was 70% (268/385) of complete response and half-time PDT was 65% (252/389). Pain during illumination was significantly lower in the VAS with the half-time protocol with a mean of 5.59 (SD 1.48) vs. 6.41 (SD 1.66) in conventional PDT. No difference in adverse effects was found between protocols.

CONCLUSION

Conventional PDT with half-time illumination in multiple actinic keratosis is as effective as complete time illumination and decreased pain significantly.

Regression Analysis of Protoporphyrin IX Measurements Obtained During Dermatological Photodynamic Therapy

Photodynamic therapy (PDT) is a light activated drug therapy that can be used to treat a number of dermatological cancers and precancers. Improvement of efficacy is required to widen its application. Clinical protoporphyrin IX (PpIX) fluorescence data were obtained using a pre-validated, non-invasive imaging system during routine methyl aminolevulinate (MAL)-PDT treatment of 172 patients with licensed dermatological indications (37.2% actinic keratosis, 27.3% superficial basal cell carcinoma and 35.5% Bowen’s disease). Linear and logistic regressions were employed to model any relationships between variables that may have affected PpIX accumulation and/or PpIX photobleaching during irradiation and thus clinical outcome at three months. Patient age was found to be associated with lower PpIX accumulation/photobleaching, however only a reduction in PpIX photobleaching appeared to consistently adversely affect treatment efficacy. Clinical clearance was reduced in lesions located on the limbs, hands and feet with lower PpIX accumulation and subsequent photobleaching adversely affecting the outcome achieved. If air cooling pain relief was employed during light irradiation, PpIX photobleaching was lower and this resulted in an approximate three-fold reduction in the likelihood of achieving clinical clearance. PpIX photobleaching during the first treatment was concluded to be an excellent predictor of clinical outcome across all lesion types.

The background and philosophy behind daylight photodynamic therapy

Conventional photodynamic therapy (PDT) is associated with side effects, primarily related to the waiting time between pretreatment with application of photosensitizer and illumination. Pain during illumination is a major issue for the patients and options for effective pain relief are limited. Post-treatment inflammation can often be severe and cause inconvenient down-time for the patients and their employers. To avoid the problems of pain and patients crowding in the clinic we eliminated red light treatment of high PpIX concentration and introduced illumination in daylight which may be performed at home. We also investigated if protoporphyrin IX (PpIX) could be activated continuously during its formation which might reduce pain and inflammation. Continuous activation of PpIX during its formation turned out to minimize pain as single PpIX molecules are activated continuously without accumulation of PpIX in the skin. PpIX molecules are formed in the mitochondria and the photodynamic effect only takes place in the mitochondria when continuously activated. This results primarily in apoptosis with little inflammation. Continuous activation of PpIX can be obtained by performing photodynamic therapy in daylight, as well as with daylight-emitting light sources of appropriate wavelengths. Use of daylight prevents the patients from crowding in the clinic. Daylight-PDT completely fulfils the purpose of minimizing pain and inflammation, as well as limiting the strain on the clinic treating the patients.

Protoporphyrin IX formation after application of methyl aminolevulinate on the face and scalp with and without prior curettage

BACKGROUND

Pulse photodynamic therapy (PDT) is carried out as classical PDT except that methyl aminolaevulinate (MAL) is removed after 30 min. Protoporphyrin IX (PpIX) accumulation becomes lower after 3 h in pulse-PDT than in classical PDT, but pulse-PDT still has full treatment effect on actinic keratosis (AK). The present study aimed to investigate when PpIX formation in classical PDT without curettage reaches the PpIX level in pulse-PDT with curettage in the skin of the face and scalp.

METHODS

Fourteen patients with AKs in the face and scalp were included in this pilot study. Each patient had two fields randomly allocated to two different regimes: (i) continuing MAL incubation without prior curettage (-Cur) and (ii) 30 min MAL incubation after curettage (+Cur). The PpIX level in each field was measured with a hand-held fluorescence photometer every 30 min for 6 h after MAL application. No illumination was performed.

RESULTS

The median PpIX level in the +Cur field after 3 h was 22 arbitrary units (AU), which represents the amount of PpIX that could have been photobleached after pulse-PDT with maximal treatment effect. After 3 h the median PpIX level in the -Cur field was 20 AU, which was not significantly different from the level in the +Cur field (p = 0.9).

CONCLUSIONS

We propose PDT without curettage as follows: 3 h of MAL incubation and subsequently sufficient illumination. The treatment effect of this regime should be tested to verify if curettage of the face and scalp area may be omitted in PDT.