Effectiveness of Photodynamic Therapy in Elimination of HPV‐16 and HPV‐18 Associated with CIN I in Mexican Women

Abstract

This study aimed to determine the effectiveness of photodynamic therapy (PDT), using δ-aminolevulinic acid (5-ALA), in the elimination of premalignant cervical lesions in Mexican patients with human papillomavirus (HPV) infection and/or cervical intraepithelial neoplasia (CIN). Thirty women diagnosed with CIN I and/or positive for HPV participated in the study. Topical 6% 5-ALA in gel form was applied to the uterine cervix; after 4 h, the lesion area was irradiated with a light dose of 200 J cm at 635 nm. This procedure was performed three times at 48-h intervals. Clinical follow-up was performed at 3, 6, and 12 months after the initial PDT administration, by colposcopy, cervical cytology, histopathological analysis, polymerase chain reaction, and hybrid capture. Of HPV-infected patients without evidence of CIN I, 80% cleared the infection, while HPV associated with CIN I was eliminated in 83% of patients (P < 0.05). At 12 months, CIN I had regressed in 57% of patients, although this response was not statistically significant. PDT using 6% 5-ALA is concluded to be effective in eliminating HPV infection associated or not with CIN I.

Photodetection and Safety of 5‐Aminolevulinic Acid‐Induced Porphyrin in Patients With Cervical Intraepithelial Neoplasia

“…Concentrations of drugs in ineffective PDT studies were 20%, 20%, and 3%–5%, respectively, and application times were 90 minutes, 3–5 hours, and 4 hours, respectively [8–10]. In the effective PDT studies [16,17,21,22], the drug concentrations were 6%, 11.8%, 12%, and 20%, and the application times were 4, 3–4, 8, and 3 hours, respectively. Overall, in effective studies, the application time was more than 3–4 hours, and the drug concentration was more than 6%.…”

“…However, when the drug concentration reached 20% and the application time reached 3 hours, the result of PDT was still ineffective [9]. It is worth noting that the dosage forms of 20% 5-ALA used in the above ineffective studies were aqueous solutions [8,9], while in effective PDT studies, gels or dispersants were used [16,17,21,22]. According to the characteristics of 5-ALA for local external use in PDT, the gel is more uniform than a solution.…”

Topical photodynamic therapy in the treatment of benign oral mucosal lesions: A systematic review

“…In some cases, such as the one treated by Casu et al 39 on RAS, patients are not responsive to traditional therapy and, in particular, to corticosteroids; in these cases, PDT is a valid alternative method. Furthermore, PDT has also effectively treated infectious diseases in other medicine branches, with only a few studies dealing with this tool applied to the oral mucosa 47‐49 . Although the results look promising, further studies are needed on this topic.…”

Vitamin D and Other Differentiation‐promoting Agents as Neoadjuvants for Photodynamic Therapy of Cancer

“…Tumors in these squamous epithelial tissues begin as superficial pre-carcinomas, before undergoing further neoplastic progression and deep invasion. Situations in which ALA-based photodiagnosis and PDT are showing great promise for early detection and treatment include dysplasia and carcinoma in situ of the oral cavity (14,15), cervix (11)(12)(13), and bladder (22,23). For all of these conditions, the use of vitamin D in combination with ALA-PDT makes sense conceptually.…”

“…Use of ALA (Levulan, Ameluz) or ALA methyl-ester (Metvix) as prodrugs to drive PpIX generation is now the most prevalent form of PDT used in dermatology for treating skin cancer (8)(9)(10). ALA and its esters have also been explored for a number of internal malignancies including cancers of the gynecologic tract (11)(12)(13), oral cavity (14,15), head and neck (16)(17)(18) and brain (19)(20)(21). Besides PDT, ALA is proving valuable as a tool for photodiagnosis.…”