***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: Background Increasing clinical data supports a low α/β ratio for prostate adenocarcinoma , potentially lower than that of surrounding normal tissues . A hypofractionated , weekly radiation therapy ( RT ) schedule should result in improved tumour control , reduced acute toxicity , and similar or decreased late effects . We report the toxicity profile of such treatment . Material s and Methods We conducted a multi-institution phase I/II trial of three-dimensional conformal radiation therapy ( 3D-CRT )  for favourable-risk prostate cancer ( T1a-T2a , Gleason ≤ 6 and PSA < 10 ng/ml ) .  RT consisted of 45 Gy in nine 5 Gy fractions , once weekly . Primary end-points were feasibility and late gastrointestinal ( GI ) toxicity ( RTOG scale ) , while secondary end-points included acute GI toxicity , acute and late genitourinary ( GU ) toxicity , biochemical control , and survival . Results Between 2006 and 2008 , 80 patients were treated . No treatment interruptions occurred . The median follow-up is 33 months ( range : 20 - 51 ) . Maximal grade 1 , 2 , and 3 acute ( < 3 months ) GU toxicity was 29 % , 31 % and 5 % respectively ( no grade 4 ) . Acute GI grade 1 toxicity was reported in 30 % while grade 2 occurred in 14 % ( no grade 3 or 4 ) . Crude late grade ≥ 3 toxicity rates at 31 months were 2 % for both GU and GI toxicity . Cumulative late grade ≥ 3 GI toxicity at 3 years was 11 % . Two patients  had PSA failure according to the Phoenix definition . The three-year actuarial biochemical control rate is 97 % . Conclusions Weekly RT with 45 Gy in 9 fractions is feasible and results in comparable toxicity . Long term tumour control and survival remain to be assessed BACKGROUND / AIM Based on a radiobiological assumption of a low alpha/beta ( α/β ) ratio for prostate cancer , hypofractionated radiotherapy has increasingly gained traction in the clinical practice and recent guidelines have confirmed the non-inferiority of this approach . Nevertheless , the largest studies that have used hypofractionation so far , employed image-guided radiation therapy/intensity modulated radiation therapy ( IGRT/IMRT ) facilities that might have overcome the radiobiological advantages , which remain to be fully confirmed . The aim of this trial was to evaluate the feasibility of a hypofractionated schedule delivered with 3D-Conformal Radiotherapy to prostate and seminal vesicles in combination with hormonal therapy . PATIENTS AND METHODS The study included 97 consecutive patients with localized prostate cancer ( PCa ) , irrespective of risk class , treated with a schedule of 62 Gy in 20 fractions over 5 weeks ( 4 fractions of 3.1 Gy each per week ) . According to National Comprehensive Cancer Network ( NCCN ) prognostic classification , patients were divided into a favourable group ( 19 % ) , intermediate group ( 41 % ) and unfavourable group ( 40 % ) . Early and late toxicities were scored using the radiation toxicity grading/European Organisation for Research and Treatment of Cancer ( RTOG/EORTC ) criteria . Additionally , the international prostate symptom index ( IPSS ) for benign prostate hypertrophy was used to evaluate obstructive urinary symptoms . Biochemical outcome was reported according to the Phoenix definition for biochemical failure  . Hormonal therapy ( HT ) was administrated in 92 % of patients . RESULTS After a median follow-up of 39 months ( range=25 - 52 ) , maximum ≥G2 late genitourinary ( GU ) and gastrointestinal ( GI ) toxicities occurred in 8 % and 11 % patients , respectively . The corresponding figures for acute toxicities were 24 % and 15 % . Patients with higher IPSS score before enrolment had significantly worse urinary function after treatment . Only 2 % of patients died from PCa . Biochemical non- evidence of disease ( bNED ) was 83 % for all patients . CONCLUSION Our study confirms that 3D conformal radiotherapy ( 3DCRT ) remains a safe and effective method to deliver a dose-escalated hypofractionated regimen for PCa patients in all risk classes with acceptable toxicity rates and optimal biochemical control Objective : To report on the design , methodology , and early outcome results of a multi-institutional registry study of prostate cancer radiosurgery . Methods : The Registry for Prostate Cancer Radiosurgery ( RPCR ) was established in 2010 to further evaluate the efficacy and toxicity of prostate radiosurgery ( SBRT ) for the treatment of clinical ly localized prostate cancer . Men with prostate cancer were asked to voluntarily participate in the registry . Demographic , baseline medical , and treatment-related data were collected and stored electronically in a Health Insurance Portability and Accountability Act-compliant data base , maintained by Advertek , Inc. Enrolled men were asked to complete short , multiple choice question naires regarding their bowel , bladder , and sexual function . Patient-reported outcome forms were collected at baseline and at regular intervals ( every 3–6 months ) following treatment . Serial prostate-specific antigen measurements were obtained at each visit and included in the collected data . Results : From July 2010 to July 2013 , nearly 2000 men from 45 participating sites were enrolled in the registry . The majority ( 86 % ) received radiosurgery as monotherapy . At 2 years follow-up , biochemical disease-free survival was 92 % . No Grade 3 late urinary toxicity was reported . One patient developed Grade 3 gastrointestinal toxicity ( rectal bleeding ) . Erectile function was preserved in 80 % of men < 70 years old . Overall compliance with data entry was 64 % . Conclusion : Stereotactic radiosurgery is an alternative option to conventional radiotherapy for the treatment of organ-confined prostate cancer . The RPCR represents the collective experience of multiple institutions , including community-based cancer centers , with outcome results in keeping with published , prospect i ve trials of prostate SBRT Background and purpose For localized prostate cancer , treatment options include external beam radiotherapy ( EBRT ) , radical prostatectomy ( RP ) , and brachytherapy ( BT ) .  Erectile dysfunction ( ED ) is a common side-effect . Our aim was to evaluate penile erectile function ( EF ) before and after BT , EBRT , or RP using a vali date d self-administered quality -of-life survey from a prospect i ve registry . Material and methods Analysis included 478 patients undergoing RP ( n = 252 ) , EBRT ( n = 91 ) , and BT ( n = 135 ) with at least 1 year of follow-up and EF documented using IIEF-5 scores at baseline , 6 weeks , 6 months , 1 year , and annually thereafter . Results Differences among treatments were most pronounced among patients with no or mild initial ED ( IIEF-5 ≥ 17 ) . Overall , corrected for baseline EF and age , BT was associated with higher IIEF-5 scores than RP ( + 7.8 IIEF-5 score ) or EBRT ( + 3.1 IIEF-5 score ) . EBRT was associated with better IIEF-5 scores than RP ( + 4.7 IIEF-5 score ) . In patients undergoing EBRT or RP with bilateral nerve sparing ( NS ) , recovery of EF was observed and during follow-up , the differences to BT were not statistically significant . Overall age had a negative impact on EF preservation ( corrected for baseline IIEF ) . Conclusion In our series , EF was adversely affected by each treatment modality . Considered overall , BT provided the best EF preservation in comparison to EBRT or RP.ZusammenfassungHintergrund und ZielDie externe Radiotherapie ( EBRT ) , die radikale Prostatektomie ( RP ) sowie die Brachytherapie ( BT ) stellen Beh and lungsoptionen für das lokalisierte Prostatakarzinom dar . Die erektile Dysfunktion ( ED ) ist eine häufige Nebenwirkung dieser Therapien . Unser Ziel war es , die penile erektile Funktion ( EF ) vor und nach BT , EBRT und RP mit Hilfe eines validierten , vom Patienten ausgefüllten Lebensqualitätsfragebogens aus einer prospektiven Date nbank zu beurteilen . Material und Method enMit einer minimalen Nachbeobachtungszeit von einem Jahr wurden 478 Patienten analysiert , die eine RP ( n = 252 ) , EBRT ( n = 91 ) oder BT ( n = 135 ) erhalten hatten und deren EF mit dem IIEF-5-Score vor Therapie sowie nach 6 Wochen , 6 Monaten , nach einem Jahr und danach jährlich ermittelt worden sind . ErgebnisDie größten therapiebedingten Unterschiede wurden bei Patienten ohne oder nur mit milder initialer ED beobachtet ( IIEF-5 ≥ 17 ) . Korrigiert für die EF und das Alter bei Therapie , war die BT mit höherem IIEF-5-Score assoziiert als die RP ( + 7,8 IIEF-5-Score ) oder die EBRT ( + 3,1 IIEF-5-Score ) . Die EBRT war mit einem besseren IIEF-5-Score assoziiert als die RP ( + 4,7 IIEF-5-Score ) . Bei Patienten mit bilateraler nervenschonender RP oder einer EBRT wurde eine Erholung der EF beobachtet ; i m Verlauf war der Unterschied zur BT nicht mehr statistisch signifikant . Insgesamt hatte ein höheres Alter einen negativen Einfluss auf die Erhaltung der EF ( korrigiert für Ausgangs-EF).SchlussfolgerungIn unserer Serie verschlechterte sich die EF durch alle Therapieformen . Insgesamt bot die BT die beste EF-Erhaltung verglichen mit der EBRT oder RP PURPOSE To compare the toxicity between hypofractionation vs. conventional fractionation schedules in patients with high-risk prostate cancer . METHODS AND MATERIAL S Between January 2003 and December 2007 , 168 patients were r and omized to receive either hypofractionated ( 62 Gy in 20 fractions within 5 weeks , 4 fractions/wk ) or conventionally fractionated ( 80 Gy in 40 fractions within 8 weeks ) three-dimensional conformal radiotherapy to the prostate and seminal vesicles . All patients had undergone a 9-month course of total and rogen deprivation , with radiotherapy starting 2 months after initiation of the total and rogen deprivation . RESULTS The median follow-up was 32 and 35 months in the hypofractionation and conventional fractionation arms , respectively . For the patients developing acute toxicity , no difference between the two fractionation groups was found in either severity or duration of gastrointestinal or genitourinary toxicity . Also , no difference was found in the incidence and severity of late gastrointestinal and genitourinary toxicity between the two treatment schedules , with a 3-year rate of Grade 2 or greater toxicity of 17 % and 16 % for the hypofractionation arm and 14 % and 11 % for the conventional fractionation arm , respectively . A statistically significant correlation between acute and late gastrointestinal toxicity was found only in the conventional fractionation group . CONCLUSION Our findings suggest that the hypofractionation regimen used in our study is safe , with only a slight , nonsignificant increase in tolerable and temporary acute toxicity compared with the conventional fractionation schedule . The severity and frequency of late complications was equivalent between the two treatment groups PURPOSE To compare the toxicity and efficacy of hypofractionated ( 62 Gy/20 fractions/5 weeks , 4 fractions per week ) vs. conventional fractionation radiotherapy ( 80 Gy/40 fractions/8 weeks ) in patients with high-risk prostate cancer . METHODS AND MATERIAL S From January 2003 to December 2007 , 168 patients were r and omized to receive either hypofractionated or conventional fractionated schedules of three-dimensional conformal radiotherapy to the prostate and seminal vesicles . All patients received a 9-month course of total and rogen deprivation ( TAD ) , and radiotherapy started 2 months thereafter . RESULTS The median ( range ) follow-up was 32 ( 8 - 66 ) and 35 ( 7 - 64 ) months in the hypofractionation and conventional fractionation arms , respectively . No difference was found for late toxicity between the two treatment groups , with 3-year Grade 2 rates of 17 % and 16 % for gastrointestinal and 14 % and 11 % for genitourinary in the hypofractionation and conventional fractionation groups , respectively . The 3-year freedom from biochemical failure ( FFBF ) rates were 87 % and 79 % in the hypofractionation and conventional fractionation groups , respectively ( p = 0.035 ) . The 3-year FFBF rates in patients at a very high risk ( i.e. , pretreatment prostate-specific antigen ( iPSA ) > 20 ng/mL , Gleason score > or=8 , or T > or=2c ) , were 88 % and 76 % ( p = 0.014 ) in the former and latter arm , respectively . The multivariate Cox analysis confirmed fractionation , iPSA , and Gleason score as significant prognostic factors . CONCLUSIONS Our findings suggest that late toxicity is equivalent between the two treatment groups and that the hypofractionated schedule used in this trial is superior to the conventional fractionation in terms of FFBF BACKGROUND Studies have reported a low α/β ratio 
    Output:
    
Results Several large-scale trials on moderate hypofractionation with single doses from 2.4–3.4 Gy have recently finished recruiting or have published first results suggestive of equivalent outcomes although there might be a trend for increased short-term and possibly even long-term toxicity .