***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: OBJECTIVE To perform a phase I study of topically applied dihematoporphyrin ether ( DHE ) in the photodynamic treatment ( PDT ) of cervical intraepithelial neoplasia ( CIN ) using fixed DHE doses and application schedules , and a variable dose of 630 nm red light delivered by an argon-pumped dye laser . METHODS Between February 1993 and April 1994 , 24 nonpregnant women with a histologic diagnosis of CIN were enrolled . All patients had lesions involving at least 25 % of the cervix that were colposcopically visible . Using a cervical cap , 2 ml of a 1 % solution of DHE ( Photofrin ) in a 4 % Azone and isopropyl alcohol vehicle were applied to the cervix 24 hr prior to PDT . An argon-pumped dye laser providing light at 630 nm was then used to perform PDT . Light was coupled into a 400-microm silica fiber optic terminating in a microlens which focused the laser radiation onto a circular field of uniform light intensity perpendicular to the tissue . The entire ectocervix was treated in a single field including a margin of 3 - 5 mm of normal cervix . Using a constant power density ( 150 mW/cm2 ) to avoid thermal injury , the PDT energy was increased every 4 patients in a phase I fashion ( 40 , 60 , 80 , 100 , 120 , and 140 J/cm2 ) . RESULTS Thirteen patients with CIN I , 7 patients with CIN II , and 4 patients with CIN III were treated . The maximal energy density was well tolerated . Toxicity was minimal with no patients experiencing local necrosis , sloughing , or scarring ; however , a mild vaginal discharge was noted in several patients . Systemic effects were absent . After 12 months of follow-up at 3-month intervals , 22 patients are evaluable of whom 15 ( 68 % ) are disease free . One patient was lost to follow-up and in another the cervical cap was dislodged . Four of the 7 failures or recurrences occurred at energy densities of 80 J/cm2 or less , while 8 of 11 ( 73 % ) patients were treated successfully with PDT at an energy density of 100 to 140 J/cm2 . CONCLUSIONS PDT with DHE and an argon-pumped dye laser at 630-nm wavelength delivering an energy density of 140 J/cm2 is safe and effective in treating CIN . Phase II studies using PDT at the prescribed application schedule and dose are indicated OBJECTIVE The objective of the study was to investigate the efficacy and safety of hexaminolevulinate ( HAL ) photodynamic therapy ( PDT ) , a novel therapy for women with cervical intraepithelial neoplasia (CIN)1/2 , to define the appropriate population and endpoints for a phase 3 program . STUDY DESIGN This was a double-blind , r and omized , placebo-controlled , dose-finding study that included a total of 262 women with biopsy-confirmed CIN 1/2 based on local pathology . Patients received 1 or 2 topical treatments of HAL hydrochloride 0.2 % , 1 % , 5 % , and placebo ointment and were evaluated for response after 3 - 6 months based on biopsy , Papanicolaou test , and oncogenic human papillomavirus ( HPV ) test . All efficacy analyses were performed on blinded central histology review to avoid interreader variability . Adverse events , blood biochemistry , and vital signs were assessed after 3 months . RESULTS There were no statistically significant differences between placebo and either the CIN 1 or combined CIN 1/2 population s. A clear dose effect with a statistically significant response in the HAL 5 % group of 95 % ( 18/19 patients ) compared to 57 % ( 12/21 patients ) in the placebo group ( P < .001 ) was observed at 3 months in women with CIN 2 , including an encouraging 83 % ( 5/6 patients ) clearance of HPV 16/18 compared to 33 % ( 2/6 patients ) in the placebo group at 6 months . The treatment was easy to use and well accepted by patients and gynecologists . Only local self-limiting adverse reactions including discharge , discomfort , and spotting were reported . CONCLUSION HAL PDT is a novel therapy that shows promise in the treatment of CIN 2 including clearance of oncogenic HPV , but not of CIN 1 . The positive risk/benefit balance makes HAL PDT a tissue-preserving alternative in women of childbearing age who wish to preserve the cervix . Confirmatory studies are planned We have analyzed the results of photodynamic therapy using light-sensitizing agent " Photogem " in 72 patients - 56 women with pre-cancerous lesions of cervix and 16 women with early cervical cancer ( group 1 ) ;  Photosens  in 47 patients - 35 women with pre-cancerous lesions ( CIN III ) , 12 women with non-invasive cervical cancer ( carcinoma in situ ) ( group 2 ) ; and  Alasens in 22 patients - 8 women with virus-associated pre-cancerous lesions ( high- grade CIN III ) , 14 with virus-associated early cervical cancer ( carcinoma in situ , cervical cancer 1A1 ) ( group 3 ) . The results were as follows : group 1 - complete regression of CIN III and non-invasive cervical cancer ( carcinoma in situ ) was achieved in 50 ( 89.2 % ) and 11 ( 68.8 % ) cases , significant regression was achieved in 2 cases ( 3.6 % ) and in 2 cases ( 12.5 % ) , stabilization was achieved in 2 cases ( 3.6 % ) and in 2 cases ( 12.5 % ) , progression was achieved in 2 cases ( 3.6 % ) and in 1 case ( 6.2 % ) accordingly . In the group of patients after PDT using Photosens  complete regression of CIN III and non-invasive cervical cancer ( carcinoma in situ ) was achieved in 33 cases ( 94.2 % ) and in 10 cases ( 83.4 % ) cases , significant regression was achieved in 1 case ( 2.9 % ) and in 1 case ( 8.3 % ) , stabilization was achieved in 1 cases ( 2.9 % ) and in 1 cases ( 8.3 % ) . In the group of women after surgical treatment anti-viral efficacy was assessed . It s necessary to note that not a single relapse was observed . Anti-viral effect was registered in 49 ( 90.4 % ) cases The longest HPV-free period that we observed was 5 years . 12 women with CIN III and 4 women with carcinoma in situ became pregnant Objective To study the effect of cervical screening on incidence of cervical cancer as a function of age with particular focus on women screened under the age of 25 . Design Population based case-control study with prospect ively recorded data on cervical screening . Setting Selected centres in the United Kingdom . Participants 4012 women aged 20 - 69 with invasive cancer diagnosed in participating centres and two controls per case individually matched on age and area of residence . Main outcome measures Odds ratios for strength of association between cervical cancer and screening at particular ages . Results There is no evidence that screening women aged 22 - 24 reduced the incidence of cervical cancer at ages 25 - 29 ( odds ratio 1.11 , 95 % confidence interval 0.83 to 1.50 ) . Similar results were seen for cancers restricted to squamous carcinoma or FIGO ( International Federation of Gynaecology and Obstetrics ) stage IB or worse , but the numbers are insufficient to provide narrow confidence intervals . Screening was associated with a 60 % reduction of cancers in women aged 40 , increasing to 80 % at age 64 . Screening was particularly effective in preventing advanced stage cancers . Conclusions Cervical screening in women aged 20 - 24 has little or no impact on rates of invasive cervical cancer up to age 30 . Some uncertainly still exists regarding its impact on advanced stage tumours in women under age 30 . By contrast , screening older women leads to a substantial reduction in incidence of and mortality from cervical cancer . These data should help policy makers balance the impact of screening on cancer rates against its harms , such as overtreatment of lesions with little invasive potential OBJECTIVE The aim of this study was to evaluate the efficacy of 5-aminolevulinic acid-mediated photodynamic therapy ( PDT ) on cervical condylomata accuminate ( CA ) and to determine the ultrastructural changes of the lesion after treatment . BACKGROUND DATA Although there are many methods to treat cervical CA , a high recurrence rate and cervical scars are troublesome problems . MATERIAL S AND METHODS Forty-eight patients with cervical CA were treated with topical 20 % ALA gel followed by PDT through a cylindrical fiber with a wavelength of 630 nm of laser light . The treatment was repeated 7 days later if the lesion had not been removed completely . Eight cases were biopsied before and after treatment , and the biopsied lesions were evaluated by electron microscopy . RESULTS After the first PDT treatment , the cervical condylomatous lesions were removed completely in 62.5 % ( 30/48 ) . The complete response ( CR ) rate was 95.8 % ( 46/48 ) after three treatments . The recurrence rate was 4.4 % at the 12-month follow-up . Electron microscopy revealed that ALA-PDT damaged proliferative keratinocytes of CA lesions while the surrounding normal tissue injury was less damaged . CONCLUSIONS ALA-PDT is an effective and minimally invasive treatment for cervical CA 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 DESIGN S/ MATERIAL S 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 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/cm2 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 63 
    Output:
    
Conclusions : PDT that targets CIN or cervical HPV infection improves the CRR , but slightly compromises safety .