Photodynamic therapy using topically applied dihematoporphyrin ether in the treatment of cervical intraepithelial neoplasia

Locally Administered Photodynamic Therapy for Cancer Using Nano-Adhesive Photosensitizer

Photodynamic therapy (PDT) is a great potential anti-tumor therapy owing to its non-invasiveness and high spatiotemporal selectivity. However, systemically administered photosensitizers diffuse in the skin and the eyes for a long duration, which cause phototoxicity to bright light and sunlight. Therefore, following PDT, patients must avoid exposure of to light and sunlight to avoid this phototoxicity. In this study, we have developed a locally administered PDT using nano-adhesive porphyrin with polycations consisting of quaternary ammonium salt groups (aHP) as a photosensitizer. The aHP, approximately 3.0 nm in diameter, adhered the negatively charged cell membrane via electrostatic interaction. The aHP localized to the endosome via cell adhesion and induced apoptosis upon 635 nm light irradiation. On being administered subcutaneously on the tumor, 30% of the injected aHP remained in the administered sites. However, low-molecular-weight hematoporphyrin dihydrochloride (HP) disappeared due to rapid diffusion. PDT with locally administered aHP showed a higher anti-tumor effect after light irradiation at 635 nm for three days compared to low-molecular-weight HP. Intraperitoneal administration of HP caused severe phototoxicity upon irradiation with ultraviolet A at 10 J cm-2, whereas aHP did not cause phototoxicity because its diffusion into the skin could be suppressed, probably due to the high-molecular weight of aHP. Therefore, locally administered PDT with aHP is a potential PDT having high therapeutic efficacy without phototoxicity.

CD44 Receptor-Mediated/Reactive Oxygen Species-Sensitive Delivery of Nanophotosensitizers against Cervical Cancer Cells

Stimulus-sensitive, nanomedicine-based photosensitizer delivery has an opportunity to target tumor tissues since oxidative stress and the expression of molecular proteins, such as CD44 receptors, are elevated in the tumor microenvironment. The aim of this study is to investigate the CD44 receptor- and reactive oxygen species (ROS)-sensitive delivery of nanophotosensitizers of chlorin e6 (Ce6)-conjugated hyaluronic acid (HA) against HeLa human cervical cancer cells. For the synthesis of nanophotosensitizers, thioketal diamine was conjugated with the carboxyl group in HA and then the amine end group of HA-thioketal amine conjugates was conjugated again with Ce6 (Abbreviated as HAthCe6). The HAthCe6 nanophotosensitizers were of small diameter, with sizes less than 200. Their morphology was round-shaped in the observations using a transmission electron microscope (TEM). The HAthCe6 nanophotosensitizers responded to oxidative stress-induced changes in size distribution when H₂O₂ was added to the nanophotosensitizer aqueous solution, i.e., their monomodal distribution pattern at 0 mM H₂O₂ was changed to dual- and/or multi-modal distribution patterns at higher concentrations of H₂O₂. Furthermore, the oxidative stress induced by the H₂O₂ addition contributed to the disintegration of HAthCe6 nanophotosensitizers in morphology, and this phenomenon accelerated the release rate of Ce6 from nanophotosensitizers. In a cell culture study using HeLa cells, nanophotosensitizers increased Ce6 uptake ratio, ROS generation and PDT efficacy compared to free Ce6. Since HA specifically bonds with the CD44 receptor of cancer cells, the pretreatment of free HA against HeLa cells decreased the Ce6 uptake ratio, ROS generation and PDT efficacy of HAthCe6 nanophotosensitizers. These results indicated that intracellular delivery of HAthCe6 nanophotosensitizers can be controlled by the CD44 receptor-mediated pathway. Furthermore, these phenomena induced CD44 receptor-controllable ROS generation and PDT efficacy by HAthCe6 nanophotosensitizers. During in vivo tumor imaging using HeLa cells, nanophotosensitizer administration showed that the fluorescence intensity of tumor tissues was relatively higher than that of other organs. When free HA was pretreated, the fluorescence intensity of tumor tissue was relatively lower than those of other organs, indicating that HAthCe6 nanophotosensitizers have CD44 receptor sensitivity and that they can be delivered by receptor-specific manner. We suggest that HAthCe6 nanophotosensitizers are promising candidates for PDT in cervical cancer.

Microfluidic system with light intensity filters facilitating the application of photodynamic therapy for high-throughput drug screening

BACKGROUND

Photodynamic therapy utilizes light energy with a photosensitizer (a light-sensitive drug) to kill cancer cells through light activation. When a photosensitizer is injected into the bloodstream and exposed to a specific wavelength of light, it generates oxygen to destroy or damage nearby cancer cells, while minimizing side effects on normal cells. Although photodynamic therapy is effective for treating cancer, various parameters, such as the optimum light intensity and photosensitizer dose, are currently poorly understood due to the complexity of conventional experimental schemes.

METHODS

To effectively perform a simultaneous single parallel test for several different light irradiation conditions on each cell, a microfluidic device was developed to generate eight different intensities from a single light-emitting diode source, through eight different color dye concentrations functioning as light intensity filters. To show that this novel high-throughput microfluidic system can analyze the effects of various light intensities during photodynamic therapy, the optimum light intensities and photosensitizer doses were determined for two different cancer cell lines.

RESULTS

Optimum light intensities and photosensitizer were determined for all cell lines. The photodynamic therapy effects in response to different irradiated light intensities were characterized by analyzing cell viability after photosensitizer treatment CONCLUSIONS: : The developed platform is capable of being used as a photodynamic therapy screening tool. The proposed platform provides a simple and robust way to optimize the combined parameters of light intensity and dosage for diverse types of cancer cells.

Redox-Sensitive and Folate-Receptor-Mediated Targeting of Cervical Cancer Cells for Photodynamic Therapy Using Nanophotosensitizers Composed of Chlorin e6-Conjugated β-Cyclodextrin via Diselenide Linkage

The aim of this study was to fabricate a reactive oxygen species (ROS)-sensitive and folate-receptor-targeted nanophotosensitizer for the efficient photodynamic therapy (PDT) of cervical carcinoma cells. Chlorin e6 (Ce6) as a model photosensitizer was conjugated with succinyl β-cyclodextrin via selenocystamine linkages. Folic acid (FA)-poly(ethylene glycol) (PEG) (FA-PEG) conjugates were attached to these conjugates and then FA-PEG-succinyl β-cyclodextrin-selenocystamine-Ce6 (FAPEGbCDseseCe6) conjugates were synthesized. Nanophotosensitizers of FaPEGbCDseseCe6 conjugates were fabricated using dialysis membrane. Nanophotosensitizers showed spherical shapes with small particle sizes. They were disintegrated in the presence of hydrogen peroxide (H₂O₂) and particle size distribution changed from monomodal distribution pattern to multimodal pattern. The fluorescence intensity and Ce6 release rate also increased due to the increase in H₂O₂ concentration, indicating that the nanophotosensitizers displayed ROS sensitivity. The Ce6 uptake ratio, ROS generation and cell cytotoxicity of the nanophotosensitizers were significantly higher than those of the Ce6 itself against HeLa cells in vitro. Furthermore, the nanophotosensitizers showed folate-receptor-specific delivery capacity and phototoxicity. The intracellular delivery of nanophotosensitizers was inhibited by folate receptor blocking, indicating that they have folate-receptor specificity in vitro and in vivo. Nanophotosensitizers showed higher efficiency in inhibition of tumor growth of HeLa cells in vivo compared to Ce6 alone. These results show that nanophotosensitizers of FaPEGbCDseseCe6 conjugates are promising candidates as PDT of cervical cancer.

Clinical treatment of intra-epithelia cervical neoplasia with photodynamic therapy

OBJECTIVES

This clinical study was developed to primarily evaluate the Complete Cytopathological Response Rate of Cervical Intraepithelial Neoplasms to PDT using chitosan nanocapsules containing Chlorocyan-aluminum phthalocyanine as a photoactive agent. Analyses of the Free Recurrence Interval, toxicity profile (immediate and late), and complications (immediate and late), were secondarily analyzed.

METHODS

This study was previously approved by the National Council of Ethics in Research of Brazil (CONEP), on May 28, 2014, under case number 19182113.4.0000.5009. On the surface of the cervix of each selected patient was applied one mL of the formulated gel, and after 30 min, the light was applied. Reports or the identification of adverse effects and/or complications were observed in follow-up visits, in addition to the collection of cervical oncotic cytology.

RESULTS

Out of the total group, 11 (91.7%) primarily treated patients evolved with negative cervical oncotic cytology as soon as in the first evaluation following treatment, and one did not achieve any therapeutic benefit, even after reapplication. Two patients with initially positive response presented cytological recurrence determined by histopathology. A new round of PDT was developed, and both evolved with cytological remission three weeks later, remaining negative until the last follow-up. No important side effects were observed in all the patients.

CONCLUSIONS

Our trial demonstrates that treatment of CIN 1 and 2 lesions using our PDT formulation is feasible and safe. Large randomized clinical trials are required to establish efficacy.

Efficacy of commercially available biological agents for the topical treatment of cervical intraepithelial neoplasia: a systematic review

BACKGROUND

Cervical cancer is a major public health issue in the world, especially in developing countries. It can be prevented through vaccination against HPV (primary prevention) and through screening and treatment of cervical intraepithelial neoplasia (CIN) (secondary prevention). Surgical methods for treatment of CIN are linked to complications such as bleeding and adverse pregnancy outcomes. Furthermore, these methods are not generally available in resource-poor settings. Therefore, topical agents for local application on the cervix have been used since decades to overpass complications and limitations of the surgical methods.

AIMS

Review of the literature on the efficacy of commercially available biological agents used for topical treatment of cervical intraepithelial neoplasia (CIN).

METHODS

A systematic search through PubMed and the Cochrane database was performed up to December 2017, using the medical subheadings (MesH) for topical agent, treatment, and cervical intraepithelial neoplasia. Appropriate inclusion/exclusion criteria have been used for the selection of eligible clinical studies. Clinical studies containing a minimum of 20 women, aged 18-50 with a diagnosis of CIN 1-3, and at least a 4 weeks follow-up after the end of the topical treatment were included.

RESULTS

The initial electronic database search resulted in a total of 849 articles. After screening titles and abstracts, 62 articles were selected as potential studies. Of these, six articles were included in the review after reading the full text: two were on 5-FluoroUracil, two on trans retinoic acid, one on Imiquimod, and one on Cidofovir. The reported regression/remission rates for CIN differed among studies. In CIN2 patients, the overall remission rate ranged between 43 and 93% for the active agents.

CONCLUSION

Among the topical agents studied, 5-FluoroUracil showed good remission rates above 80%. Varying results seen in this review is due to the differences in quality of the design between studies. Large-scale and less biaised studies are needed to elucidate the true efficacy and safety of topical agents in the treatment of CIN.

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.

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.

Can a less radical surgery using photodynamic therapy with acridine orange be equal to a wide-margin resection?

BACKGROUND

Wide-margin resections are an accepted method for treating soft tissue sarcoma. However, a wide-margin resection sometimes impairs function because of the lack of normal tissue. To preserve the normal tissue surrounding a tumor, we developed a less radical (ie, without a wide margin) surgical procedure using adjunctive photodynamic therapy and acridine orange for treating soft tissue sarcoma. However, whether this less radical surgical approach increases or decreases survival or whether it increases the risk of local recurrence remains uncertain.

QUESTIONS/PURPOSES

We determined the survival, local recurrence, and limb function outcomes in patients treated with a less radical approach and adjunctive acridine orange therapy compared with those who underwent a conventional wide-margin resection.

METHODS

We treated 170 patients with high-grade soft tissue sarcoma between 1999 and 2009. Fifty-one of these patients underwent acridine orange therapy. The remaining 119 patients underwent a conventional wide-margin resection for limb salvage surgery. We recorded the survival, local recurrence, and functional score (International Society of Limb Salvage [ISOLS]) score) for all the patients.

RESULTS

The 10-year overall survival rates in the acridine orange therapy group and the conventional surgery group were 68% and 63%, respectively. The 10-year local recurrence rate was 29% for each group. The 5-year local recurrence rates for Stages II, III, and IV were 8%, 36%, and 40%, respectively, for the acridine orange group and 13%, 27%, and 33%, respectively, for the conventional surgery group. The average ISOLS score was 93% for the acridine orange group and 83% for the conventional therapy group.

CONCLUSION

Acridine orange therapy has the potential to preserve limb function without increasing the rate of local recurrence. This therapy may be useful for eliminating tumor cells with minimal damage to the normal tissue in patients with soft tissue sarcoma.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of the levels of evidence.

In vitro and in vivo matrix metalloproteinase expression after photodynamic therapy with a liposomal formulation of aminolevulinic acid and its methyl ester

Photodynamic therapy (PDT) is a well-known method for the treatment of malignant tumors, and its principles have been well established over the past 30 years. This therapy involves the application of a chemical called a photosensitizer and its subsequent excitation with light at the appropriate wavelength and energy. Topical photodynamic therapy with aminolevulinic acid (5-ALA) is an alternative therapy for many malignant processes, including nonmelanoma skin cancers such as basal-cell carcinoma (BCC). Our novel approach for this study was to use a liposomal formulation of 5-ALA and its methyl ester (commercially available as metvix) both in vitro and in vivo, and to check whether the liposome-entrapped precursors of photosensitizers can induce the expression of metalloproteinases (MMPs) in animal tumor cells and in other tissues from tumor-bearing rats and in selected cell lines in vitro. We also checked whether the application of tissue inhibitors of matrix metalloproteinases (TIMPs) has any effect on MMPs in the above-mentioned experimental models, and if they can cause complete inhibition of MMP expression. Immunohistochemical studies revealed that after the PDT, the intensity of expression of MMPs in healthy animals was very low and seen in single cells only. After the PDT in tumor-bearing rats, MMP-3 was expressed in the tumor cells with the highest intensity of staining in the tissues directly adjacent to the tumors, while MMP-2 and -9 were not found. In the control groups, there was no observed expression of MMPs. In vitro studies showed that MMP-3 was expressed in MCF-7 cells after PDT, but MMP-9 was not observed and MMP-2 was only seen in single cases. Our studies confirmed that the application of an MMP-3 inhibitor may block an induction of MMP-3 expression which had previously been initiated by PDT. The preliminary data obtained from cancer patients revealed that new precursors are effective in terms of PDT, and that using MMP inhibitors should be considered as a potential enhancing factor in clinical PDT.

Design and evaluation of a water-soluble bioadhesive patch formulation for cutaneous delivery of 5-aminolevulinic acid to superficial neoplastic lesions

Photodynamic therapy of superficial neoplastic lesions generally uses high aminolevulinic acid (ALA) loadings (20%, w/w) in emulsion-type systems under occlusion. This approach makes ALA dosing difficult and delivery to demanding areas, such as the vulval, perineal and perianal skin, are seldom possible. This work evaluated a water-soluble bioadhesive patch, loaded with ALA, which can adhere to both intact skin and mucous surfaces. ALA loading in the patch (38 mg cm(-2)) was chosen using a simple comparative procedure. Tensile measurements showed that large ALA loadings did not adversely affect adhesion to porcine skin, achieving a mean strength of 1.7 N cm(-2). Increasing the loading was, however, shown to lower break strength and enhance percentage elongation at break. Water uptake studies showed an initial, rapid weight gain followed by gradual patch dissolution over 60 min. Drug release studies demonstrated that 57% of ALA was released across an aqueous semi-permeable membrane within 6 h, compared to 42% released from a proprietary cream formulation. The patch designed in this work is suited to definable ALA delivery to diverse regions, such as the lower female reproductive tract and lesions on exposed skin. Adhesion is sufficiently tenacious to allow photodynamic therapy (PDT), without the need to immobilise patients for up to 6 h, as was common with the cream-under-occlusion approach.

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.

Phototoxicity of 5-aminolevulinic acid in the HeLa cell line as an indicative measure of photodynamic effect after topical administration to gynecological lesions of intraepithelial form

PURPOSE

The depth-resolved pattern of aminolevulinic acid (ALA) concentration in excised vaginal tissue was determined after in vitro application of an ALA-loaded bioadhesive patch. From this data, the tissue concentration of ALA achievable at a specified depth from the surface could be related to the concentration needed to elicit a photodynamic effect in a model gynecological tumor cell line (HeLa).

METHODS

Excised vaginal tissue was mounted in a modified Franz diffusion cell and exposed to a water-soluble, ALA-loaded, bioadhesive patch. After a period of time, the tissue was cryostatically sectioned and the stratal concentration of radiolabeled ALA determined using scintillation spectroscopy. HeLa cells were cultured in media containing specific concentrations of ALA and exposed to standard photodynamic protocols of light exposure.

RESULTS

An ALA concentration of 65.6 mM was achievable at 2.375 mm from the tissue surface after application of ALA-loaded patch. The photodynamic effectiveness of this concentration was demonstrated in HeLa with exposure to concentrations exceeding 1.0 mM ALA bringing about reductions in viable cell numbers by 90%. An enhancement of PpIX production using adjunctive EDTA over the clinically relevant 4 h application time interval was shown to be minimal in HeLa. Instead, PpIX production was more closely correlated with ALA concentration, with 100 mM ALA producing approximately 3100 ng PpIX mg(-1) protein in the same time period.

CONCLUSIONS

Given that vaginal intraepithelial neoplasias can extend to 2.0 mm from the lesion surface, the ALA permeability derived from a bioadhesive patch is sufficient to induce photosensitization suitable for light induced destruction at deep sites of this type of lesion.

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

BACKGROUND AND OBJECTIVES

To determine the safety and efficacy of 5-aminolevulinic acid (ALA) as a topically applied photosensitizer for photodynamic therapy (PDT) of cervical intraepithelial neoplasia (CIN).

STUDY DESIGNS/MATERIALS AND METHODS

Forty women, who were at least 18 years old with persistent biopsy-proven CIN 2 and CIN 3 within the previous 3 months of enrollment, underwent PDT in a phase I and II design. Five escalating radiant energies (increments of 25 J/cm(2), beginning at 50-150 J/cm(2)) using a Coherent Dye Model 920 argon pumped dye laser providing light at 630 nm (maximum output 0.8 W) were used to perform PDT with a fixed dose of ALA (200 mg/ml). ALA was placed in a cervical cap fitted to the cervix. After 90 minutes, the cap was removed and the ectocervix was illuminated for 5-16 minutes, depending on the irradiance. Success was defined as the absence of CIN on Pap smear or colposcopic examination at 12-months. Patients were monitored for toxicity.

RESULTS

Thirty-two women (80%) completed the study with 1 year of follow-up. Sixty percent had CIN 3 and 40% CIN 2. Success rates at 4, 8, and 12 months were 51, 46, and 31%, respectively, and were not light-dose dependent. Three patients progressed from CIN 2 to CIN 3. Toxicity was tolerable and only consisted of spotting, vaginal discharge, mild cramping, and vaginal warmth. There was no apparent dose relationship to toxicity.

CONCLUSIONS

PDT at this light and ALA dose is well tolerated but has minimal activity in the treatment of CIN 2 and CIN 3. Other doses and schedules of light and ALA or novel photosensitizers may improve efficacy.

Management of precursor lesions of cervical carcinoma: history, host defense, and a survey of modalities

Before the initiation of screening and treatment for cervical cancer precursors, approximately 3% to 4% of women were destined to eventually develop cervical cancer. During the last 50 years the rate of cervical cancer incidence and mortality has decreased by more than 75% primarily because of the widespread availability of cervical cytologic screening and of treatment for documented cervical precancer. Successful screening of the entire population and appropriate treatment of lesions could theoretically reduce this risk to one tenth of the risk of an unscreened population [7,28]. The relatively recent understanding of the etiology of cervical cancer precursor lesions and of the immune response to them has given new direction to management options that incorporate healthy habits and dietary measures as part of traditional ablative or excisional treatment options. As we look to the future we can expect that new markers that more specifically identify individuals at-risk for cervical precancer and cancer will be developed and take precedence in cervical screening. At the same time, treating the cause of these lesions, rather than the result, should provide less traumatic and more successful therapies. To this end, harnessing the immune system through immune response modifiers and HPV vaccines seems to be on the horizon, as do new chemopreventative approaches. Of all human cancers, only cervical cancer, once the second most common cancer among women, stands on the threshold of being virtually eliminated.

Detection of female lower genital tract dysplasia using orally administered 5-aminolevulinic acid induced protoporphyrin IX: a preliminary study

OBJECTIVE

Previous studies have suggested that 5-aminolevulinic acid (ALA) may be used topically on the cervix to allow optical detection of cervical dysplasia, based on the fluorescence of protoporphyrin IX (PpIX) synthesized in situ from ALA. However, the uniformity of distribution of topically applied PpIX and the sensitivity and specificity of detection are not optimal. The current study was undertaken to demonstrate the feasibility of administering ALA by mouth (po) with the hypothesis that systemic administration might provide a more reliable diagnostic tool.

METHODS

Oral ALA was administered to 14 patients with abnormal Pap smears in a dose- and time-intensity design. Institutional review board approval was obtained. A starting dose of 10 mg/kg of po ALA was administered and colposcopy was performed in 3 patients at 1 h, 3 patients at 2 h, 6 patients at 3 h, and 2 patients at 4 h. The study was written with the intent to increase the dose in 10 mg/kg increments if fluorescence was not detected; however, fluorescence was detected at the first dose level. Liver function tests were checked pre and post ALA and follow-up telephone calls were made regarding possible side effects. Both white and blue light colposcopy examinations were performed by two blinded clinicians and biopsies of all abnormal areas were performed.

RESULTS

All patients tolerated po ALA well, with no systemic side effects. At the 10 mg/kg dose there was no reported nausea or photosensitivity. Optimal fluorescence was achieved at the 3-h time point, with quenching noted at the 4-h time point. Excellent absorption was documented with fluorescence of the lip demonstrated with Wood's lamp. In some cases fluorescence correlated with dysplasia on biopsy.

CONCLUSION

5-ALA given via the po route and at the dose and time period studied is well tolerated and affords fluorescence of the cervix. Future study is needed to demonstrate the successful identification of dysplastic lesions, with the ultimate goal of treating dysplasia of the lower genital tract with 5-ALA and light therapy.

Photodynamic effects induced by aminolevulinic acid esters on human cervical carcinoma cells in culture

Fluorescence diagnosis and photodynamic therapy using 5-aminolevulinic acid (ALA) provide new methods for the detection and treatment of cervical cancer and especially its precursors. However, these techniques are restricted by the rate of uptake of the hydrophilic ALA, its poor diffusion through the bilayer of biological membranes or both. In this study we evaluated the effect of some esterified ALA derivatives on the induction of the endogenous photosensitizer, protoporphyrin IX (PpIX), and the photodamage in cultured human cervical cells (C33-A and CaSki). The kinetics of PpIX accumulation showed that ALA esters, especially the ALA-hexylester (h-ALA), induced significantly faster PpIX formation than ALA at the same concentration (0.5 mM). The PpIX induction showed a dose-dependent characteristic. The highest PpIX values could be achieved by an up to 1.3-13-fold lower concentration of ALA esters than with ALA. Using the Annexin V assay, apoptosis was found to be induced rapidly after irradiation in both ALA- and ALA esters-treated cells. On measuring mitochondrial activity, the incubation with h-ALA induced a more pronounced photodamage. The results indicate that improved or at least comparable photodynamic effects can be achieved by using remarkably lower doses of ALA esters.

Fluorescence detection of cervical intraepithelial neoplasia for photodynamic therapy with the topical agents 5-aminolevulinic acid and benzoporphyrin-derivative monoacid ring

OBJECTIVE

The aim of this study was to determine whether 2 photosensitizers, benzoporphyrin-derivative monoacid ring and 5-aminolevulinic acid, are selectively absorbed by dysplastic cervical cells after topical administration.

STUDY DESIGN

This phase I clinical trial involved 18 women with biopsy-proven cervical intraepithelial neoplasia at the Beckman Laser Institute, Irvine, Calif. Colposcopically directed cervical biopsy specimens obtained after 1.5, 3, or 6 hours of exposure to a randomly assigned photosensitizer were evaluated for selective drug absorption with hematoxylin and eosin staining and fluorescence microscopy.

RESULTS

After exposure to 5-aminolevulinic acid, cervical tissue showed maximal fluorescence in dysplastic cells relative to normal cells, with negligible stromal fluorescence. According to our detection methods benzoporphyrin-derivative monoacid ring demonstrated nonselective, diffusion-driven uptake, with fluorescence appearing in the superficial cells, followed by nonselective drug absorption in the remaining cells and stroma of the epithelium.

CONCLUSION

Our data demonstrated selective absorption of 5-aminolevulinic acid by dysplastic cervical cells. This agent therefore represents a promising photosensitizing prodrug for the treatment of cervical intraepithelial neoplasia with photodynamic therapy.

Photodynamic therapy of vulvar intraepithelial neoplasia using 5-aminolevulinic acid

Photodynamic (PDT) therapy is a relatively new technique with unique properties that make it attractive for the local treatment of superficial epithelial disorders. The objective of this study was to investigate the clinical response of PDT with the photosensitizing agent 5-aminolevulinic acid (5-ALA) in patients with vulvar intraepithelial neoplasia (VIN) grades 1 to 3. Twenty-five patients with 111 lesions of VIN 1-3 were topically sensitized with 10 ml of a 20% solution of 5-ALA and treated with 57 cycles of laser light at 635 nm (100 J/cm(2)). Seventy (64%) of the 111 VIN lesions regressed after various PDT cycles. A complete response was achieved in 13 patients (52%) with 27 lesions. All patients with VIN 1 and mono- and bifocal VIN 2-3 showed complete clearance. However, a complete response could be achieved in only 4 (27%) of 15 women with multifocal VIN 2-3, whereas a partial response was noted in 9 of these patients with a total of 70 lesions, out of which 44 (63%) lesions disappeared. No response was seen in 2 patients with multifocal VIN 3. Histological assessment of the fluorescence-directed biopsies revealed that increased pigmentation and hyperkeratosis of the lesions were associated with low response rates. PDT using 5-ALA represents an alternative treatment modality for VIN which is easy to perform and has the advantage of minimal tissue destruction, low side effects and excellent cosmetic results. However, multifocal VIN disease with pigmented and hyperkeratinic lesions remains difficult to treat.

Prevention of cervix cancer

Cervix carcinoma is an important health problem world-wide, being the second most common cancer among women, ranking first in many developing countries. A number of important epidemiological risk factors have been identified as contributing to the development of CIN and invasive cervix carcinoma. Of key importance is infection with human papillomavirus (HPV), which is the primary risk factor. There are evolving primary and secondary preventive strategies that could further reduce the burden from cervical carcinoma. The possible primary preventive strategies include risk reduction, diet or dietary supplements, HPV vaccines, and other chemopreventive agents. The possible advances in secondary preventive strategies include new technologies for Pap smears, HPV typing triage, and other adjuvant screening procedures. The impact of these strategies will depend upon evidence to support their use along with the characteristics of the population and environment in which they are used.

Cidofovir, a new approach for the treatment of cervix intraepithelial neoplasia grade III (CIN III)

Cervix intraepithelial neoplasia grade III (CIN III) is an intraepithelial proliferative process with different levels of severity depending on both the extension of the proliferation in the epithelium and the presence of cellular atypia. Human papillomavirus (HPV) has been clearly associated with such lesions. The results of a preliminary study are described on the local application of cidofovir, an acyclic nucleoside phosphonate derivative with broad-spectrum anti-DNA virus activity for the treatment of CIN III. Cidofovir 1% in gel was applied three times, every other day, on the cervix of each of 15 women with biopsy proven CIN III. Within 1 month after the start of treatment, the cervix was removed surgically. Histology and human papillomavirus polymerase chain reaction (HPV-PCR) were carried out. In 7 of the 15 patients the histology showed a complete response, whereas 5 patients had a partial response characterized by the persistence of CIN II-III lesions, 1 patient had a dysplasia of lower grade (CIN I), and 2 patients did not show differences in the histology. Complete response was confirmed by PCR in 4 of the 7 patients, with complete response histologically. Cidofovir was not toxic to the normal epithelium. Cidofovir 1% gel was able to inhibit partially or completely cervical dysplasia lesions after only three applications (every other day). This effect was specific and tissue other than the dysplastic epithelium was not affected by the treatment.

Quantitative near-infrared spectroscopy of cervical dysplasia in vivo

The aims of this study were: (i) to quantify near-infrared optical properties of normal cervical tissues and high-grade squamous intra-epithelial lesions (H-SIL); (ii) to assess the feasibility of differentiating normal cervical tissues from H-SIL on the basis of these properties; and (iii) to determine how cervical tissue optical properties change following photodynamic therapy (PDT) of H-SIL in vivo. Using the frequency domain photon migration technique, non-invasive measurements of normal and dysplastic ecto-cervical tissue optical properties, i.e. absorption (mu(a)) and effective scattering coefficients, and physiological parameters, i.e. tissue water and haemoglobin concentration, percentage oxygen saturation (%SO(2)), were performed on 10 patients scheduled for PDT of histologically-proven H-SIL. Cervix absorption and effective scattering parameters were up to 15% lower in H-SIL sites compared with normal cervical tissue for all wavelengths studied (674, 811, 849, 956 nm). Following PDT, all mu(a) values increased significantly, due to elevated tissue blood and water content associated with PDT-induced hyperaemia and oedema. Tissue total haemoglobin concentration ([TotHb]) and arterio-venous oxygen saturation measured in H-SIL sites were lower than normal sites ([TotHb]: 88.6 +/- 35.8 micromol/l versus 124.7 +/- 22.6 micromol/l; %SO(2): 76.5 +/- 14.7% versus 84.9 +/- 3.4%).

5-aminolevulinic acid-mediated photodynamic therapy of intraepithelial neoplasia and human papillomavirus of the uterine cervix--a new experimental approach

The aim of this study was to treat patients for ectocervical dysplasia [cervical intraepithelial neoplasia (CIN) grades 1 and 2] and associated human papilloma virus (HPV) infections with photodynamic therapy (PDT). In 20 patients, 5-aminolevulinic acid (5-ALA, 12% w/v) was applied topically with a cervical cap 8 h prior to illumination. A thermal light source (150 W halogen lamp) emitting a broadband red light (total energy: 100 J/cm2, fluence rate: 90 mW/cm2) was used for superficial illumination of the portio. In addition, an Nd:YAG pumped dye laser (652 nm) was used to illuminate the cervical canal (total energy: 50 J/cm2, fluence rate: 300 mW/cm2). Preliminary results of follow-ups at 1, 3, 6, and 9 months posttherapy showed a cytological improvement in the grading of the PAP smears in 19 patients and the eradication of cervical HPV in 80%. These results demonstrate that ectocervical dysplasia and associated HPV infections can be treated by PDT.

Photodynamic therapy in women with cervical intraepithelial neoplasia using topically applied 5-aminolevulinic acid

Photodynamic therapy (PDT) is a novel treatment modality that produces local tissue necrosis with laser light after prior administration of a photosensitizing agent. We performed a study of topically applied 5-aminolevulinic acid (5-ALA) in the photodynamic treatment of women with high-grade cervical intraepithelial neoplasia (CIN) using fixed 5-ALA doses and application protocols derived from previous in vitro and in vivo results. Three to 5 hr prior to PDT, 10 ml of a 20% solution of 5-ALA was topically applied using a cervical cap. PDT was performed with irradiation of 100 J/cm2 at an irradiance of 100-150 mW/cm2 with an argon-ion-pumped dye laser at 635 nm. For the endocervix, a specifically designed cylindrical applicator was used. Ten treatment cycles of PDT using 5-ALA were performed in 7 patients with high-grade CIN. Non-thermal laser treatment with 100-150 mW/cm2 was well tolerated. Local toxicity was minor as several patients reported burning sensations and vaginal discharge, but no necrosis, sloughing or scarring occurred. After 3 months, a significant reduction in the size of the ectocervical CIN lesions was noted in only 3 patients, who underwent a second PDT cycle. However, no significant improvement in CIN lesions was noted since cold knife conization revealed persistent CIN in all 7 cases. Therefore, PDT after topical application of 5-ALA using an irradiation of 100 J/cm2 produces only minimal side effects. However, it does not appear to be effective in treating CIN.

Pharmacokinetics and selectivity of aminolevulinic acid-induced porphyrin synthesis in patients with cervical intra-epithelial neoplasia

Photodynamic therapy (PDT), due to its tumor selectivity, represents an alternative approach to diagnose and treat cervical intra-epithelial neoplasia (CIN) without altering normal surrounding tissue. Our aim was to investigate the pharmacokinetics and the selectivity of 5-aminolevulinic acid (5-ALA)-induced porphyrin fluorescence after topical administration, to obtain basic clinical data for future diagnostic fluorescence imaging and PDT protocols for CIN. Twenty-eight non-pregnant women with a cytological diagnosis of low-grade or high-grade squamous intra-epithelial lesions were included. An aqueous solution containing 3% 5-ALA was topically applied 1 to 6 hrs prior to conization using a cervical cap. After excision, porphyrin-induced fluorescence was quantified in dysplastic (n = 14) and normal epithelium (n = 28) by means of quantitative fluorescence microscopy. High values of porphyrin fluorescence were found in squamous epithelium between 150 and 450 min, with a maximum at 300 min following administration of 5-ALA. Ratios of porphyrin fluorescence of dysplastic vs. surrounding normal epithelium were 1.3 and 1.21 for CIN 1 (n = 3) and CIN 2 (n = 3), respectively. In CIN 3 patients (n = 8), this ratio was 2.35; the best selectivity of 5-ALA-induced porphyrin fluorescence in CIN 3 lesions (ratio 3) was observed with a topical administration time of between 150 and 250 min. Our results demonstrate that patients with CIN 3 show higher 5-ALA-induced fluorescence compared with normal epithelium. The optimal administration time of topically applied 5-ALA was between 3 and 4 hr. Our data suggest that topical ALA-PDT and photodynamic diagnosis might be suitable for detecting CIN.