Photodynamic therapy of high-grade cervical intraepithelial neoplasia with 5-aminolevulinic acid

Comparison of 5-ALA-PDT and LEEP of cervical squamous intraepithelial neoplasia (CIN2) with high-risk human papillomavirus infection in childbearing age women: A non-randomized controlled polit study

BACKGROUND

5-Aminolevulinic acid-mediated photodynamic therapy (5-ALA-PDT) is a possible minimally-invasive treatment for high-grade cervical intraepithelial neoplasia (HSIL). The present study was carried out to assess the effect of 5-ALA-PDT and loop electrosurgical excision procedure (LEEP) in cervical squamous intraepithelial neoplasia (CIN2) combined with high-risk human papillomavirus (HR-HPV) infection.

METHODS

In this study, 190 patients with CIN2 and HR-HPV infection were finally included. They were divided into the LEEP Group (n = 116) and PDT Group (n = 74) according to gynecologist's recommendation and patient's willingness. All patients were followed up at 4-6 months and 12 months after treatment, including HPV testing, cytology, and colposcopy examination.

RESULTS

(1) 4-6 months after treatment, the pathological regression rate was 97.30 % (72/74) in the PDT group and 98.28 % (114/116) in the LEEP group (P = 0.952). The HPV clearance rate was 81.08 % (60/74) in the PDT group and 80.17 % (93/116)in the LEEP group (P = 0.877). (2) 12 months after treatment, the pathological regression rate was 93.24 % (69/74) in the PDT group and 96.55 % (112/116) in the LEEP group (P = 0.486). The recurrence rate of CIN2 was 4.05 % (3/74) in the PDT group and 1.72 % (2/116) in the LEEP group (P = 0.608). The HPV clearance rate was 90.54 % (67/74) in the PDT group and 89.66 % (104/116)in the LEEP group (P = 0.843). The reinfection rate of HR-HPV was 5.41 % (4/74) in the PDT group and 1.72 % (2/116) in the LEEP group (P = 0.322). (3) The adverse reactions in the PDT Group were slightly lower than that in the LEEP Group (P = 0.4956), but the incidence of vaginal bleeding in the PDT group was lower than that in the LEEP group during follow-up.

CONCLUSIONS

The effectiveness of 5-ALA-PDT is similar to LEEP for CIN2 with less side effects. Therefore, 5-ALA-PDT, a non-invasive treatment, may be an effective method for CIN2 patients of childbearing age.

Photodynamic therapy of cervical cancer: a scoping review on the efficacy of various molecules

Background

Cervical cancer poses a considerable worldwide health issue, where infection with the human papillomavirus (HPV) plays a vital role as a risk factor. Photodynamic therapy (PDT) is a minimally invasive treatment for HPV-related cervical lesions, which uses photosensitizers and light to selectively destroy abnormal cells.

Objectives

Our objective is to present a comprehensive overview of the different types of molecules employed in PDT to reduce the occurrence and fatality rates associated with cervical cancer.

Design

Scoping review and bibliometric analysis.

Methods

The article explores clinical trials investigating the efficacy of PDT in treating low-grade squamous intraepithelial lesion and high-grade squamous intraepithelial lesion, as well as preclinical approaches utilizing various molecules for PDT in cervical cancer. Furthermore, the article sheds light on potential molecules for PDT enhancement, examining their properties through computer modeling simulations, molecular docking, and assessing their advantages and disadvantages.

Results

Our findings demonstrate that PDT holds promise as a therapeutic approach for treating cervical lesions associated with HPV and cervical cancer. Additionally, we observe that the utilization of diverse dye classes enhances the anticancer effects of PDT.

Conclusion

Among the various molecules employed in PDT, functionalized fullerene exhibits a notable inclination toward overexpressed receptors in cervical cancer cells, making it a potential candidate for intensified use in PDT. However, further research is needed to evaluate its long-term effectiveness and safety.

Rational of topical photodynamic therapy (PDT) with 5-aminolevulinic acid (5-ALA) for treatment of endocervical canal low-grade squamous intraepithelial lesion with high-risk human papillomavirus infection

BACKGROUND

The detection and continuous monitoring of low-grade squamous intraepithelial lesions (LSIL) within the endocervical canal pose considerable challenges, and the effectiveness of ablation treatment is also constrained. In this context, the potential efficacy of 5-aminolevulinic acid photodynamic therapy (5-ALA PDT) in targeting these concealed lesions merits exploration. The present study undertakes a comprehensive analysis of the clinical effectiveness and safety aspects associated with the utilization of 5-ALA PDT.

METHODS

A retrospective analysis was conducted on a cohort of 13 patients who were diagnosed with LSIL within the endocervical canal, concomitant with high-risk human papillomavirus (hrHPV) infection. These patients were subjected to treatment with 5-ALA PDT and subsequently monitored over a period of 3-6 months following the intervention.

RESULTS

The study cohort comprised 13 patients, among whom 4 presented with isolated lesions within the endocervical canal, 5 exhibited LSIL involving both the endocervical canal and the cervix vaginal portion, 3 displayed LSIL within the endocervical canal in conjunction with vaginal involvement, and 1 patient demonstrated lesions across all three of these anatomical sites. All identified lesions underwent therapeutic intervention via 5-ALA PDT. Before treatment initiation, 9 patients returned positive results in the liquid-based cytologic test (LBC), 4 displayed concurrent multiple hrHPV infections, and 5 manifested infections specifically with HPV 16/18. Subsequent to the application of 5-ALA PDT, regression was observed in the LBC results of all patients, with only 3 individuals retaining a singular type of hrHPV infection. Adverse reactions following treatment encompassed mild aberrant vaginal secretions and mild to moderately pronounced distending abdominal discomfort, all of which were remitted within a span of 7 days.

CONCLUSIONS

Within the context of LSIL within the endocervical canal in association with hrHPV infection, the findings affirm the efficacy and safety of 5-ALA PDT as a viable therapeutic modality.

Efficacy of photodynamic therapy with 5-aminolevulinic acid for the treatment of cervical high-grade squamous intraepithelial lesions with high-risk HPV infection: A retrospective study

BACKGROUND

The current principle of clinical management of cervical high-grade squamous intraepithelial lesion(HSIL) is surgical excision. However excisional procedures of the uterine cervix may have a negative impact on fertility. Topical photodynamic therapy(PDT) is a non-invasive and selective tissue destruction. We investigated the clinical efficacy of PDT for cervical HSIL with high-risk human papilloma virus(HPV) infection.

METHODS

A retrospective study consisting of 96 patients aged 20-50 years with a histologically confirmed cervical HSIL with high-risk HPV infection from July 2018 to June 2022 was carried out. Patients were treated with six times of 20% 5-aminolevulinic acid photodynamic therapy (5-ALA PDT) at intervals of 7-14 days. Three months after treatment, the effect was evaluated through HPV typing and colposcopy directed biopsy. Six and twelve months after treatment, TCT and HPV tests were carried out.

RESULTS

Three months after 5-ALA PDT treatment, among 96 HSIL with high-risk HPV infection patients, the total lesion regression rate was 89.58%(86/96), and the HPV clearance rate was 79.17 % (76/96) at 3 months follow-up. At 6 and 12 months follow-up, the patients who was HSIL pathological regression and negative HPV at 3 months follow-up continued negative results in both TCT and HPV. All patients with ineffective 5-ALA PDT treatment had persistent HPV infections. There was no significant difference in the HSIL regression rate and HPV clearance rate among different age groups. The main side effects of PDT were abdominal pain and increased vaginal secretions. Univariate analysis showed that the different severity of cervical cytology was associated with lesion regression rate in 5-ALA PDT treatment. The HSIL regression rate of TCT<ASC-H was higher than that of TCT≧ASC-H(94.59% vs 72.72%; P<0.01).Multicentric lesions,the proportion of visible lesion size in ectocervical size≥24.59%, size of visible lesion ≥1.23cm² and maximum linear length of visible lesion ≥0.90cm were risk factors of HSIL persistence after 5-ALA PDT treatment (P<0.05).

CONCLUSION

5-ALA PDT can be a safe and efficient treatment for cervical HSIL who wish to preserve fertility. 5-ALA PDT did not appear to create cervical damage and have negligible side effects. But we need evaluate the type of transformation zone, the visible lesion size, the location of lesion,baseline status of TCT and histological results before 5-ALA PDT treatment.

The effect of high-risk HPV E6/E7 mRNA on the efficacy of topical photodynamic therapy with 5-aminolevulinic acid for cervical high-grade squamous intraepithelial lesions

BACKGROUND

E6 and E7 high-risk human papillomavirus (HR-HPV) oncoproteins are closely associated with the initiation and progression of cervical cancer (CC) and pre-cancerous lesions. Cervical high-grade squamous intraepithelial lesions (HSIL), as pre-cancerous lesions, have a 5% chance of progressing to invasive cancer. Topical 5-aminolevulinic acid photodynamic therapy (ALA-PDT) is a novel non-invasive targeted therapy for intraepithelial lesions. Herein, we analyzed the effect of HR-HPV E6/E7 mRNA on ALA-PDT for cervical HSIL.

METHODS

A retrospective analysis of 148 HR-HPV-positive patients diagnosed with cervical HSIL and receiving ALA-PDT was carried out. ALA-PDT was performed with 20% ALA thermosensitive gel, and irradiation at wavelength of 635 nm and density of 80-100 J/cm² for 20-30 min. The therapeutic instruments of LED and semiconductor laser were applied for cervical lesions and lesions in endocervical canal, respectively. All patients were tested for HPV E6/E7 mRNA before and after PDT, and then followed up at 3, 6, and 12 months after treatment, and every six months thereafter.

RESULTS

At the 6-month follow up, the complete remission (CR) rate of patients' lesions was 86.5% (128/148), whereas the total HPV clearance rate was 72.3% (107/148). It was evident that positive E6/E7 mRNA before treatment had a significant effect on HPV clearance rate (66.3% VS 81.4%, P=0.045) and CR rate (80.9% VS 94.9%, P=0.015). The E6/E7 mRNA associated with HPV16/18 and HPV16/18 combined with other HR-HPV (HPV16/18 and other HR-HPV) affected HPV clearance (P=0.035) and lesions CR (P=0.039), respectively. Moreover, persistently positive E6/E7 mRNA after treatment was closely associated with poor efficacy (HPV clearance rate: P=0.000, CR rate: P=0.000). Throughout the follow up period, two cases recurred but none of the patients progressed.

CONCLUSIONS

This study has shown that ALA-PDT is an effective, safe, and alternative treatment for cervical HSIL, especially for the patients of childbearing age. However, its efficacy is relatively poor in patients with persistently positive E6/E7 mRNA before and after treatment, who are insensitive to ALA-PDT.

Phototheranostics of Cervical Neoplasms with Chlorin e6 Photosensitizer

Simple Summary

Neoplasms of the cervix are the most common types of oncological pathology. Photodynamic therapy with intravenous administration of the photosensitizer chlorin e6 shows high efficiency in the treatment of precancerous lesions of the cervix with complete eradication of the human papillomavirus. The treatment method can reduce deaths from cervical cancer and preserve fertility in patients. Spectral and video fluorescence diagnostics allows intraoperatively assessing the degree of photosensitizer accumulation and photobleaching and visualizing the boundaries of pathologically altered tissues.

Abstract

(1) Purpose: Improving the treatment effectiveness of intraepithelial neoplasia of the cervix associated with human papillomavirus infection, based on the application of the method of photodynamic therapy with simultaneous laser excitation of fluorescence to clarify the boundaries of cervical neoplasms. (2) Methods: Examination and treatment of 52 patients aged 22 to 53 years with morphologically and cytologically confirmed mild to severe intraepithelial cervix neoplasia, preinvasive, micro-invasive, and squamous cell cervix carcinoma. All patients were carriers of human papillomavirus infection. The patients underwent photodynamic therapy with simultaneous laser excitation of fluorescence. The combined use of video and spectral fluorescence diagnostics for cervical neoplasms made it possible to control the photodynamic therapy process at all stages of the procedure. Evaluation of the photodynamic therapy of intraepithelial cervical neoplasms was carried out with colposcopic examination, cytological conclusion, and morphological verification of the biopsy material after the photodynamic therapy course. The success of human papillomavirus therapy was assessed based on the results of the polymerase chain reaction. (3) Results. The possibility of simultaneous spectral fluorescence diagnostics and photodynamic therapy using a laser source with a wavelength of 660 nm has been established, making it possible to assess the fluorescence index in real-time and control the photobleaching of photosensitizers in the irradiated area. The treatment of all 52 patients was successful after the first photodynamic therapy procedure. According to the PCR test of the discharge from the cervical canal, the previously identified HPV types were not observed in 48 patients. Previously identified HPV types were absent after repeated PDT in four patients (CIN III (n = 2), CIS (n = 2)). In 80.8% of patients, regression of the lesion was noted. (4) Conclusions. The high efficiency of photodynamic therapy with intravenous photosensitizer administration of chlorin e6 has been demonstrated both in relation to eradication therapy of human papillomavirus and in relation to the treatment of intraepithelial lesions of the cervix.

Efficacy of photodynamic therapy in women with HSIL, LSIL and early stage squamous cervical cancer: a systematic review and meta-analysis

BACKGROUND

We sought to conduct a systematic review and meta-analysis of randomized and non-randomized clinical trials to assess the efficacy of photodynamic therapy (PDT) in cervical epithelial neoplasia (CIN) and early-stage cervical cancer. Additionally, according to the results, we tried to consider which stage of CIN is more sensitive to PDT.

METHODS

A systematic search was conducted using electronic databases including PubMed, ClinicalTrials.gov, the Cochrane Library, and Google Scholar.

INCLUSION CRITERIA

all patients had confirmed low-grade squamous intraepithelial lesion (LSIL), high-grade squamous intraepithelial lesion (HSIL), or an early-stage cervical cancer - the cancer is less than 3 mm deep into the cervix -IA; type of photosensitizer and any type of wavelength.

EXCLUSION CRITERIA

women who were previously treated with PDT; Risk of bias assessment was carried out for each study included in the systematic review using the Cochrane Handbook for Systematic Reviews of Interventions: RoB-2 was used to assess the risk of bias in randomized studies, while ROBINS-I - in non-randomized ones.

RESULTS

We identified 2213 publications, but only 6 met the inclusion criteria and were included in the synthesis. PDT is most effective when patients have CIN 2 or photosensitizer is administered intravenously.

CONCLUSION

Based on our systematic review and meta-analysis, it could be concluded that photodynamic therapy may be a practical approach in CIN (LSIL) regression compared with placebo. Nevertheless, we need more evidence and long-term follow-up to answer all questions thoroughly.

Efficacy and safety of photodynamic therapy mediated by 5-aminolevulinic acid for the treatment of cervical intraepithelial neoplasia 2: A single-center, prospective, cohort study

BACKGROUND

Photodynamic therapy (PDT) mediated by 5-aminolevulinic acid (5-ALA) is a minimally-invasive treatment for cervical intraepithelial neoplasia (CIN). The present study was carried out to investigate the effect of 5-ALA-PDT on CIN2 and the factors influencing outcome of 5-ALA-PDT.

METHODS

Patients diagnosed as CIN2 who met the inclusion criteria were enrolled in this study sequentially from January 2019 to April 2020. Patients were treated by PDT or cryotherapy according to their intentions. The primary endpoint was pathological regression. The secondary endpoint was HPV clearance. Affecting factors of the efficacy of PDT and adverse events were also assessed during treatment.

RESULTS

A total of 210 patients were enrolled, including 97 patients in PDT group and 101 patients in cryotherapy group, with 12 patients excluded. There was no statistical difference in population characteristics. The pathological regression rate in PDT group was 92.0% (80/87), compared with 81.4% (79/97) in cryotherapy group (P < 0.05). The HPV clearance rate was 64.4% (56/87) in PDT group and 57.8% (56/97) in cryotherapy group (P = 0.36). The main side effects of PDT were abdominal pain (24.1%, 21/87) and increased vaginal secretions (23.0%, 20/87). On univariate analysis, the risk for lesions persisting at 6 months after PDT was increased by recurrent genital tract inflammation (P = 0.004), smoking or passive smoking (P = 0.020), and multicentric lesions (P = 0.020).

CONCLUSION

PDT can be a safe and efficient treatment for CIN2. Risk factors for persisting HSIL after PDT include recurrent genital tract inflammation, smoking or passive smoking, and multicentric lesions.

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

BACKGROUND AND OBJECTIVES

5-Aminolevulinic acid (5-ALA) is a porphyrin-based photosensitizer and has been used for photodynamic therapy of cervical intraepithelial neoplasia (CIN). In this study, photodetection and safety of 5-ALA-induced porphyrin in CIN tissues were assessed.

STUDY DESIGN/MATERIALS AND METHODS

A total of 42 patients for whom colposcopy or loop electrosurgical excision procedure (LEEP) was planned were administered 10%, 20%, or 30% 5-ALA locally on the surface of the cervix for 1.5-18 hours. At different times after application, the fluorescence intensity of 5-ALA-induced porphyrin on CIN and non-CIN lesions of the cervix was detected.

RESULTS

Fluorescence intensity was correlated with drug concentration and application time. With 20% 5-ALA, the porphyrin fluorescence intensity increased over time, reaching a peak after 6 hours of application intervals in CIN. There was no significant difference in fluorescence intensity between CIN lesions and chronic cervicitis (benign tissue) or among CIN lesions of different severities. Three adverse events were considered related to the drug; however, these had no significant correlation with the drug concentration or application time.

CONCLUSIONS

5-ALA at 10%-30% concentration is safe in patients with CIN. For further treatment, we recommend the application of 20% 5-ALA, 6 hours before photodynamic therapy in CIN.

CLINICAL TRIAL REGISTRATION

This study was registered at http://www.chinadrugtrials.org.cn (registration number: CTR20130326) in accordance with the requirements of the National Medical Products Administration in China. Considering that there is no English version of the above website, we made a retrospective registration on http://www.chictr.org.cn (registration number ChiCTR1800016755) in 2018. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Laser technologies in treatment of cervical intraepithelial neoplasia (review)

This review article discusses the key aspects of the use of laser technologies, namely, laser vaporization (LV) and photodynamic therapy (PDT), in the treatment of patients with cervical intraepithelial neoplasia (CIN). The authors analyzed and systematized the foreign experience of these methods of treatment, their indications and contraindications, as well as the advantages over traditional approaches to the treatment of this pathology. The main advantages of the LV are the possibility of complete evaporation of the pathological focus, visual control over the depth of tissue destruction, the absence of prolonged edema and cicatricial deformities, which allows maintaining the integrity of the cervix and its reproductive function. Despite the low trauma and low frequency of adverse reactions, the data on the effectiveness of LV are quite contradictory and, according to various authors, vary from 50% to 98%. To date, there is a significant amount of accumulated experience in the use of PDT with various photosensitizing agents (5-aminolevulinic acid (5-ALA), hematoporphyrin and chlorin and their derivatives) in the treatment of patients with CIN. The main advantages of the PDT are minimal toxicity to the surrounding normal tissues due to the selective accumulation of photosensitizer in pathological tissues, a low risk of severe pain syndrome, the absence of mechanisms of primary and acquired resistance, the possibility of an outpatient treatment session, the possibility of combining with other methods of therapeutic action, the absence of limiting cumulative doses of photosensitizers and light exposure, the possibility of multiple repetitions of the session, good cosmetic results and the possibility of implementing an organ-preserving method of treatment. The obtained results indicate good tolerability of the method (no severe adverse reactions) and a fairly high efficiency of PDT: the frequency of complete regressions varies from 30% to 67% - for application forms of 5-ALA and from 90% to 98.1% - for hematoporifirin and chlorin photosensitizers. Thus, LV and PDT can be considered safe and effective treatment options for patients with CIN.

Efficacy of 5-aminolevulinic acid and LED photodynamic therapy in cervical intraepithelial neoplasia: A clinical trial

BACKGROUND

5-Aminolaevulinic acid (5ALA) is a precursor of the strong sensitizer protoporphyrin IX (PpIX) in the heme synthesis pathway. We conducted aclinical trial designed to evaluate the efficacy and safety of 5ALA photodynamic therapy (PDT) using a light-emitting diode (LED) in patients with cervical intraepithelial neoplasia (CIN).

METHODS

Data for 51 CIN patients who underwent 5ALA-PDT between 2012 and 2017 were prospectively analysed. After a 20 % 5ALA jelly formulation was topically applied to the cervix, the region was irradiated with red light at approximately 633 nm to excite PpIX for treatment. We estimated outcomes by cytology, pathology, and human papilloma virus (HPV) testing after PDT.

RESULTS

Patients underwent two PDT sessions at one-week intervals during outpatient treatment and achieved favourable results without photosensitivity and severe adverse events. Over a long follow-up period, 96.1 % of all patients showed some positive effects, including approximately 70 % with a complete response (CR), 10 % with a partial response, and 15 % with downgrades. The HPV clearance rate in patients with CR was 79.4 %. Recurrence occurred in five patients who mostly remained HPV-positive after PDT.

CONCLUSIONS

Based on our study, topical 5ALA-PDT using an LED light source potentially represents a safe treatment for CIN on an outpatient basis.

Clinical Trials and Basic Research in Photodynamic Diagnostics and Therapies from the Center for Laser Diagnostics and Therapy in Poland

The purpose of this review is to present an overview of the development of photodiagnostic and photodynamic therapy (PDD and PDT) techniques in Poland. The paper discusses the principles of PDD, including fluorescent techniques in determining precancerous conditions and cancers of the skin, digestive tract, bladder and respiratory tract. Methods of PDT of cancer will be discussed and the current state of knowledge as well as future trends in the development of photodynamic techniques will be presented, including the possibility of using photodynamic antimicrobial therapy. Research pioneers in photodynamic medicine such as Thomas Dougherty are an inspiration for the development of methods of PDD and PDT in our Clinic. The Center for Laser Diagnostics and Therapy in Bytom, Poland, promotes the propagation of PDD and PDT through the training of clinicians and raising awareness among students in training and the general public. Physicians at the Center are engaged in photomedical research aimed at clinical implementation and exploration of new avenues in photomedicine while optimizing existing modalities. The Center promotes dissemination of clinical results from a wide range of topics in PDD and PDT and serving as representative authorities of photodynamic medicine in Poland and Europe.

Efficacy and safety of photodynamic therapy for cervical intraepithelial neoplasia and human papilloma virus infection: A systematic review and meta-analysis of randomized clinical trials

BACKGROUND

We sought to conduct a systemic review and meta-analysis of randomized clinical trials to assess the efficacy and safety of photodynamic therapy (PDT) in cervical intraepithelial neoplasia (CIN) and cervical human papilloma virus (HPV) infection.

METHODS

The Medline, EMBASE, and Cochrane Central Register databases were searched using relevant keywords for entries up to May 1, 2017, irrespective of year of publication. The language was restricted to English. Randomized clinical trials and qualitative studies comparing PDT and placebo for CIN or HPV-positive patients were included. We assessed the evidence quality using a risk of bias graph in RevMan V5.3 and the Grading of Recommendations Assessment, Development, and Evaluation scoring system.

RESULTS

Of the 168 studies identified, only 4 RCTs met the inclusion criteria for meta-analysis. In all, 292 and 141 patients received PDT or placebo, respectively. PDT significantly increased the complete remission rate (CRR) among those with CIN (odds ratio [OR]: 2.51 [1.23-5.12]; P = .01) and HPV infection (OR: 3.82 [1.91-7.65]; P = .0002). The adverse events rate (AER) for PDT was greater than that for placebo (OR: 13.32 [4.44, 40.02]; P < .00001). The overall evidence quality was very low. Similarly, in a systematic review including 21 qualitative records, the CRRs for CIN patients with PDT and cervical HPV infection patients with PDT were 82.0% and 77.5%, respectively. The AER for PDT was 31.6%, which was lower than that observed in our meta-analysis (74.6%).

CONCLUSIONS

PDT that targets CIN or cervical HPV infection improves the CRR, but slightly compromises safety. Further studies are necessary to identify the most effective and least toxic photosensitizer.

Cisplatin and photodynamic therapy exert synergistic inhibitory effects on small-cell lung cancer cell viability and xenograft tumor growth

Lung cancer is the leading cause of cancer death worldwide. Small-cell lung cancer (SCLC) is an aggressive type of lung cancer that shows an overall 5-year survival rate below 10%. Although chemotherapy using cisplatin has been proven effective in SCLC treatment, conventional dose of cisplatin causes adverse side effects. Photodynamic therapy, a form of non-ionizing radiation therapy, is increasingly used alone or in combination with other therapeutics in cancer treatment. Herein, we aimed to address whether low dose cisplatin combination with PDT can effectively induce SCLC cell death by using in vitro cultured human SCLC NCI-H446 cells and in vivo tumor xenograft model. We found that both cisplatin and PDT showed dose-dependent cytotoxic effects in NCI-H446 cells. Importantly, co-treatment with low dose cisplatin (1 μM) and PDT (1.25 J/cm²) synergistically inhibited cell viability and cell migration. We further showed that the combined therapy induced a higher level of intracellular ROS in cultured NCI-H446 cells. Moreover, the synergistic effect by cisplatin and PDT was recapitulated in tumor xenograft as revealed by a more robust increase in the staining of TUNEL (a marker of cell death) and decrease in tumor volume. Taken together, our findings suggest that low dose cisplatin combination with PDT can be an effective therapeutic modality in the treatment of SCLC patients.

eEF1A1 binds and enriches protoporphyrin IX in cancer cells in 5-aminolevulinic acid based photodynamic therapy

Photodynamic therapy (PDT) with protoporphyrin IX (PpIX), which is endogenously derived from 5-aminolevulinic acid (5-ALA) or its derivatives, is a promising modality for the treatment of both pre-malignant and malignant lesions. However, the mechanisms of how ALA-induced PpIX selectively accumulated in the tumors are not fully elucidated. Here we discovered that eukaryotic translation elongation factor 1 alpha 1 (eEF1A1) interacted with PpIX (with an affinity constant of 2.96 × 10(6) M(-1)). Microscopy imaging showed that ALA-induced PpIX was co-localized with eEF1A1 in cancer cells. eEF1A1 was found to enrich ALA-induced PpIX in cells by competitively blocking the downstream bioavailability of PpIX. Taken together, our study discovered eEF1A1 as a novel photosensitizer binding protein, which may play an essential role in the enrichment of ALA-induced PpIX in cancer cells during PDT. These suggested eEF1A1 as a molecular marker to predict the selectivity and efficiency of 5-ALA based PDT in cancer therapy.

A Surgical View of Photodynamic Therapy in Oncology: A Review

Clinical photodynamic therapy (PDT) has existed for over 30 years, and its scientific basis has been known and investigated for well over 100 years. The scientific foundation of PDT is solid and its application to cancer treatment for many common neoplastic lesions has been the subject of a huge number of clinical trials and observational studies. Yet its acceptance by many clinicians has suffered from its absence from the undergraduate and/or postgraduate education curricula of surgeons, physicians, and oncologists. Surgeons in a variety of specialties many with years of experience who are familiar with PDT bear witness in many thousands of publications to its safety and efficacy as well as to the unique role that it can play in the treatment of cancer with its targeting precision, its lack of collateral damage to healthy structures surrounding the treated lesions, and its usage within minimal access therapy. PDT is closely related to the fluorescence phenomenon used in photodiagnosis. This review aspires both to inform and to present the clinical aspect of PDT as seen by a surgeon.

Novel bacteriochlorophyll-based photosensitizers and their photodynamic activity

Bacteriochlorin derivatives were synthesized by reacting bacteriopheophorbide methyl ether with diaminoalkanes bearing alkyl groups of different chain length. Biotests demonstrated their high in vitro phototoxicity at nanomolar concentrations against different types of epithelial cells, as well as high dose-dependent in vivo antitumor efficacy in tumor laden mice. At the doses of 2.5 and 5.0 mg/kg, the tested photosensitizers (PS) provided 100% tumor growth inhibition and 100% response rate over 120 day follow-up period after PDT due to selective accumulation in the tumor tissue and rapid clearance from the body.

Efficacy and safety of photodynamic therapy for cervical intraepithelial neoplasia: a systemic review

BACKGROUND

The current treatment of cervical intraepithelial neoplasia (CIN) is primarily based on surgical excision using laser, a loop electrosurgical procedure, or a cold knife technique. Unfortunately, these treatments often lead to obstetrical problems during the subsequent pregnancy, particularly in young women. Photodynamic therapy (PDT), which uses a topical or intravenous photosensitizer (PS) activated by a light source to ablate abnormal tissue, offers a minimally invasive alternative. The purpose of this study was to comprehensively assess the effectiveness and safety of PDT in the treatment of CIN.

METHODS

Following Cochrane guidelines, a comprehensive systematic review of all clinical studies and reports examining the use of PDT for CIN was conducted. Study quality was assessed using the Oxford Levels of Evidence Scale.

RESULTS

The 14 studies included two randomized control trials (RCTs), one case-control study, and 11 case series. Among the 506 patients studied, 472 were included to study the effectiveness of PDT on CIN and 10 were lost to follow-up. An assessment of clinical effectiveness included the response of the lesion to treatment (may include lesion recurrence) reported by all 14 studies. The complete response rate (CRR) of PDT on CIN ranged from 0% to 100%. HPV eradication rate (HER) was reported in seven studies, with rates ranging from 53.4% to 80.0%.

CONCLUSIONS

PDT is a safe and tolerable treatment for CIN. Evidence regarding the efficacy of PDT for CIN is conflicting, which may, in part, be explained by the limited number of controlled comparative clinical trials.

Photodynamic therapy of cervical intraepithelial neoplasia 1-3 and human papilloma virus (HMV) infection with methylaminolevulinate and hexaminolevulinate--a double-blind, dose-finding study

INTRODUCTION

Cervical intraepithelial neoplasia (CIN) 1-3 is the precursor of invasive cervical cancer and associated with human papillomavirus infection. Standard treatment is surgical and may be associated with subsequent pregnancy complications. Photodynamic therapy (PDT) of CIN may be an interesting alternative.

MATERIAL AND METHODS

Patients were treated by PDT using hexaminolevulinate (HAL) and methylaminolevulinate in six dose and light groups and two incubation periods in a double-blind setting. Follow-up examinations were performed after 3, 6, and 12 months with histology, cytology, and HPV testing.

RESULTS

We included eight patients with CIN1, 23 with CIN2, and 36 with CIN3. Treatment was well tolerated. HAL 40 mM with 3-hour application turned out to be the most-effective group with 67% (10/15) complete response rate. The combined complete and partial response for patients with CIN2 was 83% (20/24).

CONCLUSION

PDT with CIN may be a safe and effective procedure for CIN treatment.

Photodynamic therapy for gynecological diseases and breast cancer

Photodynamic therapy (PDT) is a minimally invasive and promising new method in cancer treatment. Cytotoxic reactive oxygen species (ROS) are generated by the tissue-localized non-toxic sensitizer upon illumination and in the presence of oxygen. Thus, selective destruction of a targeted tumor may be achieved. Compared with traditional cancer treatment, PDI has advantages including higher selectivity and lower rate of toxicity. The high degree of selectivity of the proposed method was applied to cancer diagnosis using fluorescence. This article reviews previous studies done on PDT treatment and photodetection of cervical intraepithelial neoplasia, vulvar intraepithelial neoplasia, ovarian and breast cancer, and PDT application in treating non-cancer lesions. The article also highlights the clinical responses to PDT, and discusses the possibility of enhancing treatment efficacy by combination with immunotherapy and targeted therapy.

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.

Photodynamic therapy of cervical intraepithelial neoplasia grades II and III with Photolon

The objective of the present study was to test in clinics a previously developed novel organ-saving approach for the treatment of CIN using PDT with the photosensitizer Photolon applied in women of a childbearing age with CIN II and III. A total number of 112 patients aged 35.2+/-1.6 with morphologically proven diagnosis of CIN II and III were enrolled into the study. All 112 patients had been observed at least during 1-year follow-up period after PDT. Among them 53 patients (44.1%) were subjected to a dynamic observation for less than 2 years; 29 patients (24.1%) were under the observation for less than 3 years; 13 patients (10.8%) - for 3-4 years and 17 women - for more than 4 years. A complete response represented by the complete regression of neoplastic lesions, which was proved by the results of morphological examinations, was revealed in 104 (92.8%) of treated women. In 3 months after treatment a complete eradication of the HPV infection was proven by PCR-analysis in 47 (53.4%) from 88 patients who have been infected with HPV of a highly oncogenic strains before PDT. PDT with Photolon is an alternative approach for the treatment of cervical intraepithelial neoplasia which can be recommended for women of childbearing age. The simplicity of the procedure as well as its' high therapeutic efficacy defines the reasonability of its' introduction into the clinical practice as a new organ-saving method for the treatment of patients with cervical intraepithelial neoplasia.

Photodynamic therapy for intraepithelial neoplasia of the lower genital tract

Photodynamic Diagnosis (PDD) and Therapy (PDT) are modern methods which are evaluated in different fields in gynaecology. PDT has been successfully evaluated in human papillomavirus-related (HPV) genital dysplasia like CIN and VIN. The aim of this review is to give an overview about current applications.

Successful photodynamic therapy with topical 5-aminolevulinic acid for five cases of cervical intraepithelial neoplasia

OBJECTIVES

Photodynamic therapy (PDT) is a minimally invasive treatment for cervical intraepithelial neoplasia. The purpose of this study was to assess the feasibility and effectiveness of PDT in patients with CIN and high-risk HPV infection.

METHODS

Five patients diagnosed CIN 2 or CIN 3 with human papillomavirus (HPV) infection were included. Each patient had gynecologic examination including cervical cytology, HPV DNA testing, colposcopy and biopsy. Two grams of 5-aminolevulinic acid (ALA) gel (118 mg/g) was topically applied to the cervix and covered with a special plastic cap for 3-4 h, followed by 20 min illumination of both ecto- and endo-cervical canal with red coherent light (wavelength 633 nm) using a PDT laser and a special light catheter. The PDT therapy was repeated with an interval of 1 week. Follow-up examination including biopsy and histology, colposcopy, HPV DNA testing were carried out after 3, 6 and 9 months.

RESULTS

Treatment could be accomplished in all cases and no severe side effect was encountered. All the CIN2 patients had a complete response for 9 months and one CIN3 HPV remained positive for 6 months after three or four treatments.

CONCLUSION

PDT seems to be a non-invasive, repeatable procedure for CIN and cervical HPV infection with minimal side effects and can be easily performed on outpatient basis.

[Diagnosis of cervical squamous intraepithelial lesions by fluorescence imaging: clinical feasibility study]

OBJECTIVE

Fluorescence diagnosis is still undeveloped in gynaecology. In order to diagnose and localize squamous intraepithelial lesion (SIL) of the cervix, a new method improving the low specificity of colposcopy would be useful. The goal of this study was to assess the feasibility and safety of colposcopic fluorescence diagnosis of SIL after topically application of methyl aminolevulinate (MAL).

PATIENTS AND METHODS

Patients with histologic proved cervical intraepithelial neoplasia (CIN) and planned for loop electrosurgical excision procedure (LEEP) under general anesthesia were included in a prospective study. Before general anesthesia, a thick layer of MAL (Metvix-160 mg/mL cream) was applied on the cervix for 35-150 min. Fluorescent colposcopic inspection of the cervix was performed using a rigid 10-mm laparoscope inserted in the vaginal cavity and connected to D-light AF system (Karl Storz Endoskope, Tuttlingen Germany). In order to confirm neoplasic status, fluorescent foci underwent directed punch biopsy(ies).

RESULTS

Fourteen patients were included in the study. Colposcopic fluorescence imaging revealed red fluorescent foci in 71.4% of cases (10/14) (neoplasic status of fluorescent foci was confirmed in 80%). Concerning MAL, the mean of application time was 73 min (35-150). Two cases presented a false-positive fluorescence and four cases of false-negative fluorescence. For all cases of false-negative fluorescence, application time of MAL was less than 60 min. We observed no systemic or local toxicity of MAL application in any group.

DISCUSSION AND CONCLUSION

Using topical application of MAL to the cervix, we demonstrated that fluorescence diagnosis of SIL is feasible. This study justifies the further development of fluorescence imaging that combines classical white light colposcopy with the use of a photosensitizer.

Photodynamic therapy of cervical intraepithelial neoplasia with hexaminolevulinate

BACKGROUND AND OBJECTIVE

CIN is a disease of women in their reproductive years, and treatment includes excisional techniques with increased risk of preterm deliveries. Photodynamic therapy (PDT) using topical precursor of photoactive porphyrins may be a non-invasive alternative with minimal side effects. This study assessed the feasibility and response rate of PDT with hexaminolevulinate (HAL) in cervical intraepithelial neoplasia (CIN) and human papillomavirus (HPV) infection.

STUDY DESIGN/MATERIALS AND METHODS

Twenty four patients with a CIN 2 or 3 or a persistent CIN 1 and a positive high-risk HPV-DNA test were included. Each patient had gynaecologic examination including cervical cytology, HPV DNA testing, colposcopy and biopsy. Ten milliliters of HAL-thermogel (10 mM) were topically applied to the cervix for 3-5 hours, followed by 1,000 seconds of illumination of both ecto- and endocervical canal with red coherent light (wave length 633 nm) using a PDT laser and a special light catheter. Follow-up examinations were carried out after 3 (cytology, colposcopy, HPV DNA testing, and if needed re-PDT) and 6 months.

RESULTS

Seven, 10, and 7 patients had a CIN 1, 2, or 3, respectively. Treatment could be accomplished in all cases and no severe side effects were encountered. Fifteen out of the 24 patients had a complete response (15/24 = 63%) and a HPV remission 6 months after 1-3 treatments. The remission rates were 71%, 50%, and 71% for CIN 1, 2 and 3.

CONCLUSION

HAL PDT seems to be a non-invasive, repeatable procedure for CIN and cervical HPV infection with minimal side effects which can be easily performed on outpatient basis.

Thermosetting Gel for the Delivery of 5-Aminolevulinic Acid Esters to the Cervix

5-Aminolevulinic acid (5-ALA)-mediated photodynamic therapy has been proposed as an alternative, cervix-sparing treatment for cervical intraepithelial neoplasia (CIN). In this context, topical application of 5-ALA to the cervix is beneficial due to the small necessary dose and its minimal side effects. Therefore, lipophilic 5-ALA esters, such as hexylaminolevulinate (HAL), have led to improved local bioavailability and therapeutic efficacy. Hydrogels have shown to be more appropriate for the local delivery of these derivatives, but due to the limited long-term stability of such formulations at 25 degrees C, the development of an extemporaneously prepared hydrogel targeting CIN can be advantageous. Therefore, a poloxamer 407 thermosetting gel, which is liquid at room temperature and becomes a semi-solid when in contact with the female genital tract, has been evaluated in vitro and in vivo. Rheological evaluation has shown that a 17.0% poloxamer 407 hydrogel with a sol-gel transition at 24.8 +/- 0.6 degrees C was the best formulation for easy application and optimal residence time. Furthermore, similarly to other hydrogels previously tested, such a formulation shows a more complete HAL release in vitro than conventional cream vehicles, and tends to increase porphyrin accumulation in nude mice skin. Finally, in vitro release profiles were correlated to the in vivo results.

Anal intraepithelial neoplasia and anal cancer in dermatological practice

Anal intraepithelial neoplasia is considered to be a precursor lesion of invasive anal cancer. It is now increasingly recognized in high-risk groups, such as men who have sex with men and HIV-infected patients. Human papillomaviruses are considered to be an important aetiological agent in both anal intraepithelial neoplasia and anal cancer. Dermatologists are likely to encounter these conditions among the differential diagnoses to be considered in high-risk patients presenting with perianal and anal lesions. Anal cancer rates are also increasing among the HIV-infected and HIV-non-infected population. The successful treatment of anal intraepithelial neoplasia may reduce the risk of subsequent development of anal cancer. However, current therapies for anal intraepithelial neoplasia may be associated with treatment-related morbidity and are not well validated. It is currently not proven that they reduce the likelihood of the development of anal cancer. Nevertheless, screening for anal intraepithelial neoplasia is being advocated for high-risk groups and may become standard dermatological care for these patients. In view of recent developments in the understanding of this condition, this article reviews the current understanding of anal intraepithelial neoplasia and its treatment from a dermatological perspective.

Invasive squamous cell carcinoma arising in refractory perianal Bowen's disease in a HIV-positive individual

A 54-year-old HIV-positive homosexual man presented with erythematous and pigmented plaques on background erythema in the perianal region, histologically consistent with Bowen's disease. Perianal Bowen's disease represents high-grade anal intraepithelial neoplasia, which is considered a precursor lesion of invasive anal squamous cell carcinoma. This patient's anal intraepithelial neoplasia was unresponsive to multiple treatment modalities including cryotherapy, serial curettage and cautery, topical 5-fluorouracil and 5-aminolaevulinic acid photodynamic therapy. He progressed to develop a poorly differentiated squamous cell carcinoma of the anus three and a half years after the Bowen's disease was diagnosed. The squamous cell carcinoma was treated with combined chemoradiation. A recurrence of high-grade anal intraepithelial neoplasia was noted 6 months after completion of chemoradiation.

Nature: A rich source for developing multifunctional agents. tumor-imaging and photodynamic therapy

The purpose of this review is to call attention in the use of chlorophyll-a and bacteriochlorophyll-a to develop more than 600 photosensitizers (lambda (max) 660 nm-800 nm) during the last 15 years (1990-2005) at the Photodynamic Therapy Center, Roswell Park Cancer Institute, Buffalo. This article mainly includes the chemistry, preclinical results, and brief clinical data of some of the most effective photosensitizers. The utility of the tumor-avid photosensitizers in developing multimodality agents (imaging and therapy) is also presented.

5-Aminolevulinic Acid Derivatives in Photomedicine: Characteristics, Application and Perspectives

The introduction of lipophilic derivatives of the naturally occurring heme precursor 5-aminolevulinic acid (5-ALA) into photomedicine has led to a true revival of this research area. 5-ALA-mediated photodynamic therapy (PDT) and fluorescence photodetection (FD) of neoplastic disease is probably one of the most selective cancer treatments currently known in oncology. To date, this method has been assessed experimentally for the treatment of various medical indications. However, the limited local bioavailability of 5-ALA has widely prevented its use in daily clinical practice. Although researchers were already aware of this drawback early during the development of 5-ALA-mediated PDT, only recently have well-established concepts in pharmaceutical science been adapted to investigate ways to overcome this drawback. Recently, two derivatives of 5-ALA, methylaminolevulinate (MAL) and hexylaminolevulinate (HAL), gained marketing authorization from the regulatory offices in Europe and Australia. MAL is marketed under the trade name Metvix for the treatment of actinic keratosis and difficult-to-treat basal cell carcinoma. HAL has recently been launched under the trade name Hexvix to improve the detection of superficial bladder cancer in Europe. This review will first present the fundamental concepts underlying the use of 5-ALA derivatives in PDT and FD from a chemical, biochemical and pharmaceutical point of view. Experimental evidences from preclinical data on the improvements and limits observed with 5-ALA derivatives will then be introduced. The state-of-the-art from clinical studies with 5-ALA esters will be discussed, with special emphasis placed on the process that led to the development of MAL in dermatology and to HAL in urology. Finally, we will discuss promising medical fields in which use of 5-ALA derivatives might potentially lead to further use of this methodology in photomedicine.

Photodynamic Therapy for Cervical Intraepithelial Neoplasia

OBJECTIVES

Photodynamic therapy (PDT) is a minimally invasive treatment for cervical intraepithelial neoplasia (CIN). We report the effectiveness of PDT in 105 cases of CIN.

METHODS

All patients received photofrin (PHE) 2 mg/kg intravenously and, 48-60 h later, phototherapy was performed using the Excimer dye laser or a YAG-OPO laser with an irradiation dose of 100 J/cm(2) using 630 nm wavelength.

RESULTS

Mild photosensitivity occurred in 48% (50/105) of patients. The complete response (CR) rate was 90% (94/105) at 3 months following treatment. In the remaining 11 patients, 5 patients had CIN1, 2 patients had CIN2, and 4 patients had mild cytologic findings. However, in 9 of these 11 patients, CR was achieved 6 months after PDT. In 69 patients, human papilloma virus (HPV) typing was performed before and after PDT therapy. Pre-treatment, 64 of 69 patients (93%), were HPV-positive including 30 cases of high-risk HPV (43%). Testing performed 3, 6 and 12 months following PDT revealed no HPV-DNA in 75% (52/69), 74% (48/65) and 72% (41/57) of patients. At present, the median follow-up period is 636 days (90-2,232 days). In 3 patients, recurrence requiring surgical treatment was identified at 646, 717 and 895 days after PDT.

CONCLUSIONS

PDT is an effective and minimally invasive treatment for CIN, which also appears to eradicate HPV infection.

A review of progress in clinical photodynamic therapy

Photodynamic therapy (PDT) has received increased attention since the regulatory approvals have been granted to several photosensitizing drugs and light applicators worldwide. Much progress has been seen in basic sciences and clinical photodynamics in recent years. This review will focus on new developments of clinical investigation and discuss the usefulness of various forms of PDT techniques for curative or palliative treatment of malignant and non-malignant diseases.

Photodynamic effects of Radachlorin on cervical cancer cells

PURPOSE

Photodynamic therapy (PDT) is a novel treatment modality, which produces local tissue necrosis with laser light following the prior administration of a photosensitizing agent. Radachlorin has recently been shown to be a promising PDT sensitizer. In order to elucidate the antitumor effects of PDT using Radachlorin on cervical cancer, growth inhibition studies on a HPV-associated tumor cell line, TC-1 cells in vitro and animals with an established TC-1 tumor in vivo were determined.

MATERIALS AND METHODS

TC-1 tumor cells were exposed to various concentrations of Radachlorin and PDT, with irradiation of 12.5 or 25 J/cm(2) at an irradiance of 20 mW/cm(2) using a Won-PDT D662 laser at 662 nm in vitro. C57BL/6 mice with TC-1 tumor were injected with Radachlorin via different routes and treated with PDT in vivo. A growth suppression study was then used to evaluate the effects at various time points after PDT.

RESULTS

The results showed that irradiation of TC-1 tumor cells in the presence of Radachlorin induced significant cell growth inhibition. Animals with established TC-1 tumors exhibited significantly smaller tumor sizes over time when treated with Radachlorin and irradiation.

CONCLUSION

PDT after the application of Radachlorin appears to be effective against TC-1 tumors both in vitro and in vivo.

Technique d’imagerie par fluorescence : intérêt diagnostique et thérapeutique en gynécologie

Fluorescence techniques are presently used by several medical and surgical disciplines (dermatology, pneumology, urology, gastrointestinal surgery) for the diagnosis of pre-cancerous and cancerous lesions. The technique is based on the application of 5-aminolevulinic acid (5-ALA) which induces the production of an endogen photosensitizer: protoporphyrin IX (PpIX). Fluorescence detection of the infraclinical dysplasia lesion is based on the contrast between fluorescent pathological tissue and non-fluorescent healthy tissue. Moreover, there is a correlation between the degree of tissue dysplasia and fluorescence intensity. Fluorescence imaging could allow easier detection of infraclinical lesions enabling more well-targeted treatment. In gynecology, many experimental and clinical studies have been conducted on the detection and treatment of cervical dysplasia and the diagnosis and treatment of vaginal and vulvar diseases as well as the diagnosis of peritoneal micrometastasis from ovarian cancer, the diagnosis and treatment of endometrial alterations, and the treatment of locoregional recurrent skin breast cancer. The aim of this work is to present the fundamental principles of fluorescence imaging technical and to expose the diagnostic and therapeutic prospects in gynecology.

Time-dependent hexaminolaevulinate induced protoporphyrin IX distribution after topical application in patients with cervical intraepithelial neoplasia: A fluorescence microscopy study

BACKGROUND AND OBJECTIVES

Compared to the conventional management of cervical intraepithelial neoplasia (CIN) the potential advantage of photodynamic therapy (PDT) for the treatment of cervical human papilloma virus (HPV)-related disease encompasses a minimal invasive procedure with reduced risk of profuse bleeding as a consequence of conization, and possibly more favorable long-term results avoiding cervical stenosis. At present little is known about the precise time-dependent distribution and histological localization of hexaminolaevulinate (HAL) induced protoporphyrin IX (PPIX) fluorescence in healthy tissue and in CIN. The aim of this study was to use ex vivo fluorescence microscopy to determine whether PPIX is selectively induced by neoplastic cells of the cervical epithelium at various times after topical application.

STUDY DESIGN/MATERIALS AND METHODS

Cold cream containing 0.5% HAL was applied by means of cervical cap over various periods of time. We analyzed 52 healthy cervical mucosa and 84 CINs.

RESULTS

At time delay 100 (+/-10) minutes, high epithelial fluorescence and a significant selectivity between epithelium and underlying lamina propria was found. By contrast, no significant difference between healthy and neoplastic tissues, or between low and high-grade epithelial dysplasia (P > or = 0.05), was observed at any time point.

CONCLUSIONS

Application of HAL 0.5% cream to the cervix induced selective fluorescence in epithelial cells. The optimal ratio with a homogeneous PPIX distribution was obtained after 100 ( +/- 10) minutes cream application, which should be evaluated further for PDT.

The present and future role of photodynamic therapy in cancer treatment

It is more than 25 years since photodynamic therapy (PDT) was proposed as a useful tool in oncology, but the approach is only now being used more widely in the clinic. The understanding of the biology of PDT has advanced, and efficient, convenient, and inexpensive systems of light delivery are now available. Results from well-controlled, randomised phase III trials are also becoming available, especially for treatment of non-melanoma skin cancer and Barrett's oesophagus, and improved photosensitising drugs are in development. PDT has several potential advantages over surgery and radiotherapy: it is comparatively non-invasive, it can be targeted accurately, repeated doses can be given without the total-dose limitations associated with radiotherapy, and the healing process results in little or no scarring. PDT can usually be done in an outpatient or day-case setting, is convenient for the patient, and has no side-effects. Two photosensitising drugs, porfirmer sodium and temoporfin, have now been approved for systemic administration, and aminolevulinic acid and methyl aminolevulinate have been approved for topical use. Here, we review current use of PDT in oncology and look at its future potential as more selective photosensitising drugs become available.