Improving the efficacy of photodynamic therapy for actinic keratosis: A comprehensive review of pharmacological pretreatment strategies

Treatment of nonmelanoma skin cancer with pro-differentiation agents and photodynamic therapy: Preclinical and clinical studies (Review)

Photodynamic therapy (PDT) is a nonscarring cancer treatment in which a pro-drug (5-aminolevulinic acid, ALA) is applied, converted into a photosensitizer (protoporphyrin IX, PpIX) which is then activated by visible light. ALA-PDT is now popular for treating nonmelanoma skin cancer (NMSC), but can be ineffective for larger skin tumors, mainly due to inadequate production of PpIX. Work over the past two decades has shown that differentiation-promoting agents, including methotrexate (MTX), 5-fluorouracil (5FU) and vitamin D (Vit D) can be combined with ALA-PDT as neoadjuvants to promote tumor-specific accumulation of PpIX, enhance tumor-selective cell death, and improve therapeutic outcome. In this review, we provide a historical perspective of how the combinations of differentiation-promoting agents with PDT (cPDT) evolved, including Initial discoveries, biochemical and molecular mechanisms, and clinical translation for the treatment of NMSCs. For added context, we also compare the differentiation-promoting neoadjuvants with some other clinical PDT combinations such as surgery, laser ablation, iron-chelating agents (CP94), and immunomodulators that do not induce differentiation. Although this review focuses mainly on the application of cPDT for NMSCs, the concepts and findings described here may be more broadly applicable towards improving the therapeutic outcomes of PDT treatment for other types of cancers.

Efficacy and safety of fractional carbon dioxide laser followed by 5-aminolevulinic acid photodynamic therapy for keloids

BACKGROUND

Keloids are aggressive fibroproliferative disorders that cause aesthetic and functional damage. Photodynamic therapy (PDT) has shown promise as a novel treatment for keloids. However, the limited penetration of 5-aminolevulinic acid (ALA) and unsatisfactory outcomes in dense scars hinder its effectiveness as a monotherapy. The objective of this study is to assess the efficacy and safety of fractional CO2 laser followed by 5-ALA PDT for keloids.

METHODS

A total of 12 patients with keloid were included in our study. Each lesion was pretreated by fractional CO2 laser with 26-28 W to create microthermal zones. After topical application of 5-ALA solution, an irradiation of 635 nm red light with 120 J/cm2 was performed. The treatment was repeated at least every 2 weeks. Efficacy and safety were evaluated using the Vancouver Scar Scale (VSS), the Visual Analogue Scale (VAS) for keloid-related symptoms and documentation of postoperative complications. Statistical analysis was performed to compare VSS and keloid-related symptom VAS scores of the baseline and final treatment sessions.

RESULTS

The final treatment resulted in a statistically significant decrease in all parameters of VSS and VAS for pruritus and pain compared to the baseline. Except for postoperative hyperpigmentation, no infections, scar aggravation, or recurrence were observed during at least 6 months of follow-up. Overall, patients expressed a high level of satisfaction with the treatment outcome.

CONCLUSIONS

Fractional CO2 laser followed by 5-ALA PDT is a promising method for treating keloids. However, its synergetic effects need to be validated through clinical trials involving larger patient cohorts.

Full-face ALA-PDT for facial actinic keratosis: Two case reports

We reported two cases of full-face 5-aminolevulinic acid-photodynamic therapy (ALA-PDT) for facial multiple actinic keratosis (AK). After the full-face ALA-PDT, we observed that the AK lesions on the faces of the patients were completely cleared and facial rejuvenation was achieved. In our follow-up, one patient was free of recurrence for over 13 months and the other one for over 28 months. The experience of these two cases may indicate that full-face ALA-PDT has an excellent therapeutic effect while potentially preventing the recurrence of AK.