Evaluation of photodynamic therapy using topical aminolevulinic acid hydrochloride in the treatment of condylomata acuminata: a comparative, randomized clinical trial

British association for sexual health and HIV national guideline for the management of anogenital warts in adults (2024)

This guideline offers recommendations on the diagnosis, treatment and health promotion principles needed for the effective management of human papillomavirus (HPV)-related warts at anogenital sites including the external genitals, vagina, cervix, urethra, perianus and anal canal. The guideline is aimed primarily at patients aged 16 years or older presenting to healthcare professionals working in level 3 sexual health services in the United Kingdom. However, the principles of the recommendations may be applied in other care settings, including in primary care, using locally adapted care pathways where appropriate. The management of HPV-related anogenital dysplasia or warts at other extragenital sites is outside the scope of this guideline.

The use of photodynamic therapy in medical practice

Cancer therapy, especially for tumors near sensitive areas, demands precise treatment. This review explores photodynamic therapy (PDT), a method leveraging photosensitizers (PS), specific wavelength light, and oxygen to target cancer effectively. Recent advancements affirm PDT's efficacy, utilizing ROS generation to induce cancer cell death. With a history spanning over decades, PDT's dynamic evolution has expanded its application across dermatology, oncology, and dentistry. This review aims to dissect PDT's principles, from its inception to contemporary medical applications, highlighting its role in modern cancer treatment strategies.

Photodynamic therapy in the treatment of condyloma acuminata: A systematic review of clinical trials

INTRODUCTION

Condylomata acuminata (CA) is a sexually transmitted infection with a high prevalence associated with psychosexual morbidity in both men and women of various age. Up to now, treatment modalities yield low clearance and recurrence rate (RR) and are also deemed low quality evidence-wise. Photodynamic therapy (PDT) is a novel and promising therapy to effectively cure and prevent CA recurrence.

METHOD

This systematic review was reported according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) and registered to the International Prospective Register of Systematic Review (PROSPERO) (CRD42022332760).

RESULTS

Ten studies were included in this systematic review. A significant value of complete response (CR) ranging from 63-100% in patients with genital warts after receiving several sessions of PDT. A relatively low recurrence rate was seen in all 10 studies, with an RR of less than 17%. Quality assessment of included studies reported mostly high-quality research.

CONCLUSIONS

PDT therapy resulted in a higher CR with significantly lower RR compared to other therapies. Thus, PDT can be an alternative treatment of CA with low RR and minimal side effects. Additional research, especially randomized clinical trials in various countries, is needed to further substantiate this treatment and formulate definitive protocols.

The Effect of 5-Aminolevulinic Acid Photodynamic Therapy in Promoting Pyroptosis of HPV-Infected Cells

5-aminolevulinic acid photodynamic therapy (ALA-PDT) is highly effective in the treatment of condyloma acuminata (CA). Previous research has indicated that ALA-PDT could induce cell death by different mechanisms, including apoptosis and autophagy, but the role of pyroptosis in ALA-PDT remains uncertain. Thus, this study aimed to explore whether pyroptosis is a potential mechanism of ALA-PDT killing human papillomavirus (HPV) infected cells. HPV-positive HeLa cells were exposed to ALA-PDT, then cell viability assay, lactate dehydrogenase release (LDH) assay, detection of reactive oxygen species (ROS), quantitative real-time PCR (qPCR), and western blot were used to evaluate pyroptosis induced by ALA-PDT. Results suggested that ALA-PDT enhanced the expression of NLRP3, caspase-1, GSDMD, and the production of inflammatory cytokines such as IL-1β and IL-18. In addition, ALA-PDT induced the production of ROS and led to the destruction of the cell membrane. The inhibition of pyroptosis reduced the killing of HeLa cells by ALA-PDT. This study demonstrates that ALA-PDT induces pyroptosis in HPV-positive cells, which provides some explanation for the mechanism of ALA-PDT to treat CA and HPV infection-related diseases.

Current and future direction in treatment of HPV-related cervical disease

Human papillomavirus (HPV) is the most common sexually transmitted virus in the world. About 70% of cervical cancers are caused by the most oncogenic HPV genotypes of 16 and 18. Since available prophylactic vaccines do not induce immunity in those with established HPV infections, the development of therapeutic HPV vaccines using E6 and E7 oncogenes, or both as the target antigens remains essential. Also, knocking out the E6 and E7 oncogenes in host genome by genome-editing CRISPR/Cas system can result in tumor growth suppression. These methods have shown promising results in both preclinical and clinical trials and can be used for controlling the progression of HPV-related cervical diseases. This comprehensive review will detail the current treatment of HPV-related cervical precancerous and cancerous diseases. We also reviewed the future direction of treatment including different kinds of therapeutic methods and vaccines, genome-editing CRISPR/Cas system being studied in clinical trials. Although the progress in the development of therapeutic HPV vaccine has been slow, encouraging results from recent trials showed vaccine-induced regression in high-grade CIN lesions. CRISPR/Cas genome-editing system is also a promising strategy for HPV cancer therapy. However, its safety and specificity need to be optimized before it is used in clinical setting.

Podophyllotoxin-combined 5-aminolevulinic acid photodynamic therapy significantly promotes HR-HPV-infected cell death

BACKGROUND

Human papillomavirus (HPV) infection and related diseases are difficult clinical challenges. The efficacy of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) in treating condyloma acuminata is remarkable, with high virus clearance and low recurrence rates. Podophyllotoxin (POD) is the first-line drug with a significant therapeutic effect on condyloma acuminata. However, no studies have determined whether POD-combined ALA-PDT improves high-risk (HR)-HPV-infected cell killing. We aimed to investigate whether POD-combined ALA-PDT could promote HPV-infected cell death more effectively than the single treatment and explore the underlying mechanism.

METHODS

In HeLa and SiHa cells, flow cytometry, EdU assay and LDH release test were used to detect apoptosis, cell proliferation change and necrosis, respectively. To investigate whether the combined therapy might activate apoptosis and induce endoplasmic reticulum (ER) stress, flow cytometry was used to determine intracellular levels of ROS and calcium, and Western blotting was used to determine the expression of related proteins. Mitochondrial membrane depolarization was detected by JC-1 assay. Immunofluorescence staining and Western blotting were used to detect the activation of autophagy.

RESULTS

Podophyllotoxin -combined ALA-PDT inhibited the proliferation and promoted apoptosis and necrosis more effectively than the single treatment at the same intensity and concentration. The activation of the caspase-dependent apoptosis pathway, ER stress and autophagy was more substantial in POD-combined ALA-PDT than with single treatments.

CONCLUSION

Podophyllotoxin -combined ALA-PDT effectively promoted cell death through several pathways in HeLa and SiHa cells. This combination might be a promising therapeutic strategy for the HR-HPV infection.

2019 IUSTI-Europe guideline for the management of anogenital warts

This guideline is an update of the 2011 European Guideline for the Management of Anogenital Warts. It is intended to support best practice in the care of patients with anogenital warts by including evidence-based recommendations on diagnosis, treatment, follow-up and advice to patients. It is intended for use by healthcare professionals in sexual healthcare or dermato-venereology clinics in Europe but may be adapted for use in other settings where the management of anogenital warts is undertaken. As a European guideline, recommendations should be adapted according to national circumstances and healthcare systems. Despite the availability of vaccine to prevent HPV types 6 and 11, the cause of >95% anogenital warts, they remain an important and frequent health problem. The previous systematic review of randomized controlled trials for anogenital warts was updated. The changes in the present guideline include the following: Updated background information on the prevalence, natural history and transmission of human papillomavirus (HPV) infection and anogenital warts. Key recommendations for diagnosis and treatment have been graded according to the strength of the recommendation and the quality of supporting evidence. 5-fluorouracil, local interferon and photodynamic therapy have been evaluated and included as potential second-line treatment options. Evidence of the impact of HPV vaccination on the incidence of anogenital warts has been updated.

The place of 5-aminolaevulinic acid-photodynamic therapy in the treatment landscape of urethral warts: A systematic review

BACKGROUND

Human papilloma virus (HPV) infection is the most common sexually transmitted disease worldwide and the main cause of genital warts. Clear recommendations for the management of urethral warts, which are often hard to detect and difficult to treat, are still lacking.

OBJECTIVE

To summarize all available data describing treatment modalities of urethral warts, compare their efficacy and side effects, and provide physicians a treatment strategy outline.

MATERIAL AND METHODS

Till June 2020, we conducted a systematic review of articles studying the different treatment modalities of urethral condylomas. A chi-square test was used to compare the recurrence rates between treatment modalities, the complete clearance rates at first follow-up and the rates of adverse events.

RESULTS

A total of 26 articles with 1730 patients were included in our review. 61 % of patients were deemed completely cured on the first follow-up while 21 % recurred. 5-aminolevulinic acid (ALA) mediated photodynamic therapy (PDT) was the most common treatment and yielded the lowest recurrence rate (7.5 %) followed by laser therapy (24 %) and topical therapy (31 %) (p < 0.01). ALA-PDT resulted in a higher rate of clearance on follow up (96 %) compared to laser therapy (69 %) and topical therapy (14 %) (p < 0.01). Adverse events were more frequent in the ALA-PDT group (69 %) compared to laser therapy (28 %) and topical treatment (30 %) (p < 0.01).

CONCLUSION

ALA-PDT appears to be the most effective treatment of urethral condylomas in term of clearance and recurrence rate, but with a higher risk of adverse events. Management should be tailored to the type of lesion found at presentation.

Non-Oncologic Applications of Nanomedicine-Based Phototherapy

Phototherapy is widely applied to various human diseases. Nanomedicine-based phototherapy can be classified into photodynamic therapy (PDT) and photothermal therapy (PTT). Activated photosensitizer kills the target cells by generating radicals or reactive oxygen species in PDT while generating heat in PTT. Both PDT and PTT have been employed for treating various diseases, from preclinical to randomized controlled clinical trials. However, there are still hurdles to overcome before entering clinical practice. This review provides an overview of nanomedicine-based phototherapy, especially in non-oncologic diseases. Multiple clinical trials were undertaken to prove the therapeutic efficacy of PDT in dermatologic, ophthalmologic, cardiovascular, and dental diseases. Preclinical studies showed the feasibility of PDT in neurologic, gastrointestinal, respiratory, and musculoskeletal diseases. A few clinical studies of PTT were tried in atherosclerosis and dry eye syndrome. Although most studies have shown promising results, there have been limitations in specificity, targeting efficiency, and tissue penetration using phototherapy. Recently, nanomaterials have shown promising results to overcome these limitations. With advanced technology, nanomedicine-based phototherapy holds great potential for broader clinical practice.

[Consensus on HPV of the Portuguese Society of Andrology, Sexual Medicine and Reproduction: Treatment]

The treatment of condyloma is generally a challenge in clinical practice. Although the spontaneous resolution rate is high, a significant proportion of patients seek treatment, not because of symptomatology, but mainly for aesthetic issues and concerns related to the transmission or worsening of existing lesions. The available treatments should be applied only for clinically evident macroscopic lesions. Ideally, available therapies should have rapid action onset and clearance, resolve symptoms, reduce recurrence rate and viral load, be effective in treating small lesions, and be well tolerated. However, none of the currently available treatments is clearly more effective than the others and there is no ideal treatment for all patients or for all condyloma. Therefore, the therapeutic decision should be based on the clinician's experience, available resources, lesion morphology, size, number and location, primary or recurrent lesions, disease severity, patient preference and expectations, patient's immune competence, convenience, tolerance, cost of treatment and results of previous therapies. The available treatments are divided into three groups: applied by the patient himself (imiquimod 3.75 or 5%, podophyllotoxin .5%, synecatekines 10% or 15%), applied by the health care provider (bi- and tricloacetic acids 80%-90%, intralesional interferon alpha, cryotherapy, surgical removal, electrofulguration, laser ablation) and experimental or alternative therapies (topical cidofovir, intralesional bleomycin, photodynamic therapy). Treatment methodologies can be further divided into their action - ablative or destructive treatment (cryotherapy, electrofulguration, laser ablation, surgical excision), cytotoxic or proapoptotic treatments (podophyllotoxin .5%, 5-fluoruracil, bleomycin) and immunomodulatory treatments (imiquimod 3.75% or 5%, synecatekines 10% or 15%, intralesional interferon alpha). The overall success rate of the various treatments available ranges from 23% to 94%. Only treatments that include cryotherapy or surgical excision are suitable in condyloma with any anatomical location and that have the highest success rate in monotherapy. Recurrences are common regardless of the treatment received. In contrast, immunomodulatory therapies despite having lower initial clearance rates appear to have higher probabilities of cure in the medium term, with low recurrence rates. Some treatments may be combined with each other and the effectiveness of combined therapies appears to be superior to monotherapy (proactive sequential treatment). The consensuses for the treatment of HPV also consider special situations: immunocompromised patients, meatus and intraurethral lesions and treatment of the partner.

A Critical Reappraisal of Off-Label Use of Photodynamic Therapy for the Treatment of Non-Neoplastic Skin Conditions

BACKGROUND

In the past 30 years, topical photodynamic therapy (PDT) has been investigated for the treatment of a broad spectrum of cosmetic, inflammatory, and infectious skin conditions with variable, and often contrasting, results. However, the non-expert clinician may be in difficulty evaluating these results because different sensitizers, concentrations, formulations, light sources, and irradiation protocols have been used. In addition, many of these studies have poor quality design being case reports and uncontrolled studies of few cases.

SUMMARY

With the aim to clarify the potential usefulness of PDT for the treatment of infectious and inflammatory skin diseases as well as selected cosmetic indications, we searched for randomized controlled clinical trials, non-randomized comparative studies, retrospective studies, and case series studies with a number of at least 10 patients, published since 1990. Later, we reappraised the results in order to give a simple critical overview. Key Messages: Evidence from the literature seems to strongly support the use of ALA- and MAL-PDT for the treatment of common skin diseases such as acne, warts, condylomata, and Leishmania skin infection and for photorejuvenation, i.e., the correction of selected cosmetic changes of aging and photoaging. For other disorders, the level of evidence and strength of recommendation are lower, and controlled randomized studies with prolonged follow-ups are necessary in order to assess the clinical usefulness and other potential advantages over current treatment options.

Photodynamic therapy combined with carbon dioxide laser for low-grade vaginal intraepithelial neoplasia: A retrospective analysis

OBJECTIVE

To evaluate the clinical efficacy and safety of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) combined with a carbon dioxide laser (CO₂ laser + PDT) versus CO₂ laser for the treatment of low-grade vaginal intraepithelial neoplasms (vaginal LSIL).

METHODS

We recruited 40 patients with vaginal LSIL and persistent HR-HPV infection and divided these individuals into two groups. The CO₂ laser + PDT group (20 patients) received one CO₂ laser treatment and three treatments of ALA-PDT over a one-week interval. The CO₂ laser group (20 patients) received up to three CO₂ laser treatments. All patients were followed up at 1 month, 3 month, 6 month and 1 year. Hybrid capture HPV DNA assay and colposcopic biopsy were performed for both groups before treatment and during each of the follow-ups. Adverse effects were also assessed.

RESULTS

The complete remission (CR) rates were 65 % (13/20) in the CO₂ laser group and 85 % (17/20) in the CO₂ laser + PDT group (p > 0.05). HR-HPV remission rates were 25 % (5/20) in the CO₂ laser group and 95 % (19/20) in the CO₂ laser + PDT group (p < 0.05) at one year after treatment. In the CO₂ laser group, one patient experienced severe bleeding during treatment. Twelve patients had varying degrees of adhesions and vaginal scar stenosis. One patient underwent vaginal "dead angle" after repeated CO₂ laser treatment. No severe adverse events or systemic side effects were observed in the CO₂ + PDT group.

CONCLUSION

Topical ALA-PDT combined with CO₂ laser is an effective, safe, and well-tolerated treatment for vaginal LSIL and HR-HPV infections.

European Dermatology Forum guidelines on topical photodynamic therapy 2019 Part 2: emerging indications - field cancerization, photorejuvenation and inflammatory/infective dermatoses

In addition to approved indications in non-melanoma skin cancer in immunocompetent patients, topical photodynamic therapy (PDT) has also been studied for its place in the treatment of, as well as its potential to prevent, superficial skin cancers in immune-suppressed patients, although sustained clearance rates are lower than for immune-competent individuals. PDT using a nanoemulsion of ALA in a daylight or conventional PDT protocol has been approved for use in field cancerization, although evidence of the potential of the treatment to prevent new SCC remained limited. High-quality evidence supports a strong recommendation for the use of topical PDT in photorejuvenation as well as for acne, refractory warts, cutaneous leishmaniasis and in onychomycosis, although these indications currently lack approvals for use and protocols remain to be optimized, with more comparative evidence with established therapies required to establish its place in practice. Adverse events across all indications for PDT can be minimized through the use of modified and low-irradiance regimens, with a low risk of contact allergy to photosensitizer prodrugs, and no other significant documented longer-term risks with no current evidence of cumulative toxicity or photocarcinogenic risk. The literature on the pharmacoeconomics for using PDT is also reviewed, although accurate comparisons are difficult to establish in different healthcare settings, comparing hospital/office-based therapies of PDT and surgery with topical ointments, requiring inclusion of number of visits, real-world efficacy as well as considering the value to be placed on cosmetic outcome and patient preference. This guideline, published over two parts, considers all current approved and emerging indications for the use of topical photodynamic therapy in Dermatology prepared by the PDT subgroup of the European Dermatology Forum guidelines committee. It presents consensual expert recommendations reflecting current published evidence.

Local Management of Anogenital Warts in Non-immunocompromised Adults: A Systematic Review and Meta-analyses of Randomized Controlled Trials

INTRODUCTION

Several therapeutic options are available to manage anogenital warts (AGWs). However, no hierarchy of treatments is provided in the latest European and American recommendations. This study aimed to determine the efficacy and safety of local treatments for the management of AGWs.

METHODS

A search was conducted through 12 databases from inception to August 2018. All randomized controlled trials (RCTs) in which at least one parallel treatment group composed of immunocompetent adults with AGWs received at least one provider-administered or patient-administered treatment were included. Risk of bias assessment and meta-analyses of aggregated study data were performed on the basis of the Cochrane Handbook, and quality of evidence evaluation followed the Grading of Recommendation Assessment, Development and Evaluation (GRADE) approach. Primary endpoints were complete clearance and recurrence at 3 months.

RESULTS

Seventy RCTs (9931 patients) were included. All but four RCTs had a high risk of bias. CO2 laser was slightly more efficacious than cryotherapy [risk ratio (RR) 2.05; 95% confidence interval (CI) 1.61-2.62], with fewer recurrences at 3 months (RR 0.28; 95% CI 0.09-0.89). Electrosurgery was slightly more efficacious than cryotherapy. No differences in efficacy or side effects were found between cryotherapy and imiquimod or trichloroacetic acid. Podophyllotoxin gel was slightly more efficacious than podophyllotoxin cream. 5-Fluorouracil (5-FU) was slightly more efficacious and caused less erosion than CO2 laser (RR 1.37; 95% CI 1.11-1.70).

CONCLUSION

The vast majority of included RCTs had a low level of evidence, thereby preventing the establishment of a hierarchy of treatments. Nevertheless, our results provide an overview of the main AGW treatments available for general practitioners and specialists. While provider-administered treatments are superior, patient-administered treatments (e.g., imiquimod, podophyllotoxin) are useful solutions for compliant patients.

PROTOCOL REGISTRATION

PROSPERO-CRD42015025827.

Topical 5-aminolevulinic acid photodynamic therapy for intra anal-rectal warts

Background: Condylomata acuminata (CA) are a common sexually transmitted disease. The recurrence rate of condyloma acuminatum using traditional treatments is higher than that of applying photodynamic therapy, and a variety of adverse reactions after treatment. At the same time, different parts of condyloma acuminatum after treatment recurrence rate is also different, especially for intra anal-rectal warts.Objective: To evaluate whether using photodynamic therapy (PDT) can effectively reduce recurrence of condylomata acuminata for intra anal-rectal warts.Methods: After the confirmation of the diagnosis of intra anal-rectal warts, the patients were treated with PDT with 5-aminolevulinic acid hydrochloride (ALA). PDT was performed with irradiation of 18-36 J/cm² at an irradiance of 20-40 mW/cm² with light-emitting diode (LED) light energy, wavelength 635 nm. We used a special PDT light equipment for intra anal-rectal area warts. PDT was repeated once every week for 4 weeks.Results: After PDT, the complete clearance rate was 76.1% (35 of 46 patients). At the end of the 12 weeks followed, recurrence occurred in five cases. We recorded pain in all 46 patients and the average visual analog scale (VAS) pain score was 6.96 ± 1.41 points.Conclusion: The treatment with PDT is effective in reducing the high rate of recurrence for intra anal-rectal warts. Pain is still a great challenge for the therapy.

Evaluation of human papillomavirus DNA detection-guided aminolaevulinic acid-mediated photodynamic therapy for the treatment of condyloma acuminata

BACKGROUND

Aminolaevulinic acid-mediated photodynamic therapy (ALA-PDT) is used to treat condyloma acuminata (CA), yielding a high clearance rate and low recurrence rate. Consecutive human papillomavirus (HPV) DNA detection can be used to dynamically monitor the therapeutic efficiency of PDT. Here, we evaluated the efficacy of ALA-PDT in the context of different HPV infection states.

METHODS

One hundred thirty-eight patients with HPV infection and visible anogenital warts were enrolled. Microwave or radiofrequency was used to remove visible lesions before PDT. HPV DNA detection was performed using real-time polymerase chain reaction before each PDT session and at follow-up. Treatment was halted after the patient showed two negative results for HPV DNA detection in a row.

RESULTS

Of the 138 patients enrolled in the study, 72 completed treatment. Multisite HPV-infected patients required more sessions of PDT than did single-site infected patients to reach the endpoint of treatment. Compared with patients with only external CA, individuals with internal CA required more sessions to eliminate HPV infection. The total number of PDT sessions performed in the multitype HPV-infected group was significantly higher than that in the single-type infected group. Patients with non-high-risk (HR)-HPV infection required fewer PDT sessions than did those with HR-HPV infection by the end of treatment. Sixty-nine patients were followed-up for at least 6 months, only 2.9% of whom showed recurrence.

CONCLUSIONS

Combined ALA-PDT and HPV DNA detection was an effective strategy for the treatment of CA. Patients with multisite and multitype HPV infection required more PDT sessions to eliminate the virus.

Trends and targets in antiviral phototherapy

Photodynamic therapy (PDT) is a well-established treatment option in the treatment of certain cancerous and pre-cancerous lesions. Though best-known for its application in tumor therapy, historically the photodynamic effect was first demonstrated against bacteria at the beginning of the 20^th century. Today, in light of spreading antibiotic resistance and the rise of new infections, this photodynamic inactivation (PDI) of microbes, such as bacteria, fungi, and viruses, is gaining considerable attention. This review focuses on the PDI of viruses as an alternative treatment in antiviral therapy, but also as a means of viral decontamination, covering mainly the literature of the last decade. The PDI of viruses shares the general action mechanism of photodynamic applications: the irradiation of a dye with light and the subsequent generation of reactive oxygen species (ROS) which are the effective phototoxic agents damaging virus targets by reacting with viral nucleic acids, lipids and proteins. Interestingly, a light-independent antiviral activity has also been found for some of these dyes. This review covers the compound classes employed in the PDI of viruses and their various areas of use. In the medical area, currently two fields stand out in which the PDI of viruses has found broader application: the purification of blood products and the treatment of human papilloma virus manifestations. However, the PDI of viruses has also found interest in such diverse areas as water and surface decontamination, and biosafety.

Treatment of multi-position condyloma acuminatum using topical CO2 laser combined with photodynamic therapy - Report of 6 cases

BACKGROUND

Condyloma acuminatum(CA) is a venereal disease associated with a high rate of recurrence due to the rapid replication and subtle immune escape mechanism of Human Papillomavirus(HPV). Topical CO₂ laser can remove verruca accurately. Photodynamic therapy with 5-aminolevulinic acid(PDT-ALA) is also an effective therapy which targets on HPV infected sites. Some studies demonstrate that when combined with use of CO₂ lasers, photodynamic therapy can become more effective.

METHODS

We attempted to clinically cure a series of CA grown on cervix, urethra, urinary meatus, vulva, crissum and anal canal with treatment of topical CO₂ laser combined with ALA photodynamic therapy and report herein 6 cases.

RESULTS

Topical CO₂ laser combined photodynamic therapy for CA achieved a complete response after 3 courses of treatment. No recurrence was found after 6-month follow-up in 6 cases, and the HPV PCR detection for all was changed from positive to negative.

CONCLUSION

When it comes to CA treatment, the combination of photodynamic therapy and CO₂ laser usage can give full play to their own respective superiority, and the curative effect is more significant.

Optical techniques for the diagnosis and treatment of lesions induced by the human papillomavirus - A resource letter

Human papillomaviruses (HPV) are the most common sexually-transmitted virus, and carcinogenic HPV strains are reported to be responsible for virtually all cases of cervical cancer and its precursor, the cervical intraepithelial neoplasia (CIN). About 30% of the sexually active population are considered to be affected by HPV. Around 600 million people are estimated to be infected worldwide. Diseases related to HPV cause significant impact from both the personal welfare point of view and public healthcare perspective. This resource letter collects relevant information regarding HPV-induced lesions and discusses both diagnosis and treatment, with particular attention to optical techniques and the challenges involved to the implementation of those approaches.

Therapeutic management of cutaneous and genital warts

During their lifetime, at least 10 % of the population will be infected by human papillomaviruses (HPV), clinically characterized by the formation of cutaneous or genital warts. Although warts are ubiquitous, there are no defined treatments. Especially in the first six months, warts frequently resolve without therapeutic intervention. This complicates the interpretation of study data, given that many studies do not differentiate between newly infected patients and those with infections that have persisted for a long time. Similarly, most studies do not take location, size, and thickness of lesions into account, either. The objective of the present review article is to analyze the study data currently available, taking into consideration both subtypes and locations - factors exceedingly crucial in clinical practice. In particular, the distinction between new-onset and chronic recalcitrant warts is reflected in a therapeutic algorithm. In the case of genital warts, the algorithm is more clearly determined by the extent of the area affected rather than the longevity of lesions. In immunocompetent individuals, any therapeutic intervention must be aimed at achieving complete resolution.

Sinecatechins and imiquimod as proactive sequential therapy of external genital and perianal warts in adults

This review about the proactive sequential therapy (PST) of external genital and perianal warts (EGW) is based on the most current available clinical literature and on the broad clinical experience of a group of international experts, physicians who are well versed in the treatment of human papillomavirus-associated diseases. It provides a practical guide for the treatment of EGW, including epidemiology, etiology, clinical appearance, and diagnostic procedures for these viral infections. Furthermore, the treatment goals and current treatment options, elucidating provider- and patient-applied therapies, and the parameters driving treatment decisions are summarized. Specifically, the mode of action of the topical treatments sinecatechins and imiquimod, as well as the PST for EGW to achieve rapid and sustained clearance is discussed. The group of experts has developed a treatment algorithm giving healthcare providers a practical tool for the treatment of EGW which is very valuable in the presence of many different treatment options.

In situ production of ROS in the skin by photodynamic therapy as a powerful tool in clinical dermatology

Photodynamic therapy (PDT) is a clinical modality of photochemotherapy based on the accumulation of a photosensitizer in target cells and subsequent irradiation of the tissue with light of adequate wavelength promoting reactive oxygen species (ROS) formation and cell death. PDT is used in several medical specialties as an organ-specific therapy for different entities. In this review we focus on the current dermatological procedure of PDT. In the most widely used PDT protocol in dermatology, ROS production occurs by accumulation of the endogenous photosensitizer protoporphyrin IX after treatment with the metabolic precursors 5-methylaminolevulinic acid (MAL) or 5-aminolevulinic acid (ALA). To date, current approved dermatological indications of PDT include actinic keratoses (AK), basal cell carcinoma (BCC) and in situ squamous cell carcinoma (SCC) also known as Bowen disease (BD). With regards to AKs, PDT can also treat the cancerization field carrying an oncogenic risk. In addition, an increasing number of pathologies, such as other skin cancers, infectious, inflammatory or pilosebaceous diseases are being considered as potentially treatable entities with PDT. Besides the known therapeutic properties of PDT, there is a modality used for skin rejuvenation and aesthetic purposes defined as photodynamic photorejuvenation. This technique enables the remodelling of collagen, which in turn prevents and treats photoaging stygmata. Finally we explore a new potential treatment field for PDT determined by the activation of follicular bulge stem cells caused by in situ ROS formation.

Topical PDT in the Treatment of Benign Skin Diseases: Principles and New Applications

Photodynamic therapy (PDT) uses a photosensitizer, light energy, and molecular oxygen to cause cell damage. Cells exposed to the photosensitizer are susceptible to destruction upon light absorption because excitation of the photosensitizing agents leads to the production of reactive oxygen species and, subsequently, direct cytotoxicity. Using the intrinsic cellular heme biosynthetic pathway, topical PDT selectively targets abnormal cells, while preserving normal surrounding tissues. This selective cytotoxic effect is the basis for the use of PDT in antitumor treatment. Clinically, PDT is a widely used therapeutic regimen for oncologic skin conditions such as actinic keratosis, squamous cell carcinoma in situ, and basal cell carcinoma. PDT has been shown, under certain circumstances, to stimulate the immune system and produce antibacterial, and/or regenerative effects while protecting cell viability. Thus, it may be useful for treating benign skin conditions. An increasing number of studies support the idea that PDT may be effective for treating acne vulgaris and several other inflammatory/infective skin diseases, including psoriasis, rosacea, viral warts, and aging-related changes. This review provides an overview of the clinical investigations of PDT and discusses each of the essential aspects of the sequence: its mechanism of action, common photosensitizers, light sources, and clinical applications in dermatology. Of the numerous clinical trials of PDT in dermatology, this review focuses on those studies that have reported remarkable therapeutic benefits following topical PDT for benign skin conditions such as acne vulgaris, viral warts, and photorejuvenation without causing severe side effects.

Photodynamic therapy with topical aminolevulinic acid

Photodynamic therapy (PDT) is a relatively new therapy in dermatology that uses the topical application of a porphyrin derivative to selectively destroy a cutaneous target. The action is implemented by the application of a specific light frequency. The ability of porphyrin to selectively target tumor tissue has been known since the 1960s. In the late 1970s, the underlying mechanism was defined, and Dougherty’s discovery of the first chromophore led to the production and commercialization of Photofrin^®. Many other chromophores that can act as photosensitizers have been studied since then, with aminolevulinic acid currently the most commonly used chromophore in clinical practice. PDT is simple, minimally invasive and can be administered on an outpatient basis. The efficacy of PDT has been proven for actinic keratosis, Bowen’s disease and basal cell carcinoma; another of its well-known applications is the treatment of photoaging. Indications for its use are continuously increasing, and promising results are reported for various skin diseases. In this paper we report the mechanism of action of PDT with aminolevulinic acid, the literature concerning the most common diseases treated with PDT and the subsequent level of evidence.

Needle-free injection of 5-aminolevulinic acid in photodynamic therapy for the treatment of condylomata acuminata

The external application of 5-aminolevulinic acid (ALA) in photodynamic therapy (PDT) results in a shallow penetration depth in thick or extensive condylomata acuminata (CA) lesions, thus demonstrating a poor therapeutic effect for those patients. To compare the efficacy of needle-free injection with external application of ALA in PDT for the treatment of CA, 160 CA patients with thick or extensive warts received ALA-PDT by means of external application or needle-free injection of ALA, respectively. The complete response (CR) rate and recurrence rate in the two groups were analyzed. The CR rate after the first treatment in the needle-free injection group (68.8%) was significantly higher compared with that in the external application group (52.5%; P=0.035). The recurrence rates in the needle-free injection group and external application group were 4.1 and 15.4%, respectively (P=0.022). The needle-free injection of ALA increases the therapeutic effect of PDT for CA patients with thick or extensive lesions. It shortens the treatment time and reduces the recurrence rate, and has great potential in the treatment of CA.

The combination treatment using CO₂ laser and photodynamic therapy for HIV seropositive men with intraanal warts

BACKGROUND

We evaluate the effectiveness of combination treatment using photodynamic therapy after carbon dioxide laser in preventing the recurrence of condylomata acuminata for intraanal warts in HIV positive homosexual men. A retrospective survey of 41 patients referred to the STD clinic of the Fourth People's Hospital of Shenzhen for the treatment of intraanal warts among HIV positive homosexual men between Janurary 2009 and September 2011.

METHODS

The patients who accepted CO₂ laser monotherapy for the same diagnosis were used as the comparison group. After the confirmation of the diagnosis of HIV infection and intraanal warts, the patients were treated with the combination treatment using PDT with 5-ALA thermal gel immediately after CO₂ laser ablation of the warts. PDT was performed with irradiation of 100 J/cm² at an irradiance of 100-150 mW/cm² with a semiconductor laser, wavelength 635 nm. PDT therapy was repeated twice with 2 weekly intervals. Follow up examinations including an anoscopy every 4 weeks after the latest PDT.

RESULTS

After 3 cycles of PDT treatments, 39 cases of anoscopy examination showed no new or recurrent lesions. At the end of the sixth months, recurrence occurred in 12(29%) cases. HPV 11 was present in 6 (50%) of these recurrences. HPV 6/11 or 16/18 remains positive in 19 cases (46.3%) and HPV negative in 22 cases.

CONCLUSIONS

The combination treatment with CO₂ laser and PDT is much more effective in reducing the treatment cycles and the time intervals of the whole treatment for intraanal warts in HIV infected people.

Treatment of HPV infection-associated cervical condylomata acuminata with 5-aminolevulinic acid-mediated photodynamic therapy

The aim of this study was to investigate the efficacy of 5-aminolaevulinic acid (ALA)-mediated photodynamic therapy (PDT) in treatment of human papillomavirus (HPV)-associated cervical condylomata. A total of 56 patients with cervical and external condylomata lesions were recruited for this open-label study. HPV genotyping of exfoliated cells collected from the cervix and external lesions was performed. Cervical lesions were treated with PDT by applying ALA gel (10%) to the surface of the cervix for 4 h followed by irradiating with a 635 nm laser at 100 J cm(-2). PDT was repeated at 2-week intervals if lesion and HPV infection remained. Patients were followed up for 6-24 months. Genotyping analysis revealed four HPV subtypes (HPV6, 11, 16 and 18). The overall complete remission rate of 1-4 sessions of treatments was 98.2% and the corresponding HPV clearance rate was 83.9%. Ten cases showed complete removal of cervical lesions and HPV infection after a single treatment. Recurrence rate was 3.6%. Adverse effects were minimal and no structural complications were reported. In conclusion, topical ALA PDT is safe and effective for eradicating cervical HPV infection and eliminating condylomata lesion. Its definitive role in treating cervical condylomata deserves further investigation.

Photodynamic therapy based on 5-aminolevulinic acid and its use as an antimicrobial agent

Exogenous 5-aminolevulinic acid (ALA) is taken up directly by bacteria, yeasts, fungi, and some parasites, which then induces the accumulation of protoporphyrin IX (PPIX). Subsequent light irradiation of PPIX leads to the inactivation of these organisms via photodamage to their cellular structures. ALA uptake and light irradiation of PPIX produced by host cells leads to the inactivation of other parasites, along with some viruses, via the induction of an immune response. ALA-mediated PPIX production by host cells and light irradiation result in the inactivation of other viruses via either the induction of a host cell response or direct photodynamic attack on viral particles. This ALA-mediated production of light-activated PPIX has been extensively used as a form of photodynamic therapy (PDT) and has shown varying levels of efficacy in treating conditions that are associated with microbial infection, ranging from acne and verrucae to leishmaniasis and onychomycosis. However, for the treatment of some of these conditions by ALA-based PDT, the role of an antimicrobial effect has been disputed and in general, the mechanisms by which the technique inactivates microbes are not well understood. In this study, we review current understanding of the antimicrobial mechanisms used by ALA-based PDT and its role in the treatment of microbial infections along with its potential medical and nonmedical applications.