***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: PURPOSE To perform a r and omized trial comparing 70 and 80 Gy radiotherapy for prostate cancer . PATIENTS AND METHODS A total of 306 patients with localized prostate cancer were r and omized . No and rogen deprivation was allowed . The primary endpoint was biochemical relapse according to the modified 1997-American Society for Therapeutic Radiology and Oncology and Phoenix definitions . Toxicity was grade d using the Radiation Therapy Oncology Group 1991 criteria and the late effects on normal tissues-subjective , objective , management , analytic scales ( LENT-SOMA ) scales . The patients ' quality of life was scored using the European Organization for Research and Treatment of Cancer Quality of Life Question  naire 30-item cancer-specific and 25-item prostate-specific modules . RESULTS The median follow-up was 61 months . According to the 1997-American Society for Therapeutic Radiology and Oncology definition , the 5-year biochemical relapse rate was 39 % and 28 % in the 70- and 80-Gy arms , respectively ( p = .036 ) . Using the Phoenix definition , the 5-year biochemical relapse rate was 32 % and 23.5 % , respectively ( p = .09 ) . The subgroup analysis showed a better biochemical outcome for the higher dose group with an initial prostate-specific antigen level > 15 ng/mL. At the last follow-up date , 26 patients had died , 10 of their disease and none of toxicity , with no differences between the two arms . According to the Radiation Therapy Oncology Group scale , the Grade 2 or greater rectal toxicity rate was 14 % and 19.5 % for the 70- and 80-Gy arms ( p = .22 ) , respectively . The Grade 2 or greater urinary toxicity was 10 % at 70 Gy and 17.5 % at 80 Gy ( p = .046 ) . Similar results were observed using the LENT-SOMA scale . Bladder toxicity was more frequent at 80 Gy than at 70 Gy ( p = .039 ) . The quality -of-life question naire results before and 5 years after treatment were available for 103 patients with no differences found between the 70- and 80-Gy arms . CONCLUSION High-dose radiotherapy provided a better 5-year biochemical outcome with slightly greater toxicity Background To evaluate the daily total error shift patterns on post-prostatectomy patients undergoing image guided radiotherapy ( IGRT ) with a diagnostic quality computer tomography ( CT ) on rails system . Methods A total of 17 consecutive post-prostatectomy patients receiving adjuvant or salvage IMRT using CT-on-rails IGRT  were analyzed . The prostate bed 's daily total error shifts were evaluated for a total of 661 CT scans . Results In the right-left , cranial-caudal , and posterior-anterior directions , 11.5 % , 9.2 % , and 6.5 % of the 661 scans required no position adjustments ; 75.3 % , 66.1 % , and 56.8 % required a shift of 1 - 5 mm ; 11.5 % , 20.9 % , and 31.2 % required a shift of 6 - 10 mm ; and 1.7 % , 3.8 % , and 5.5 % required a shift of more than 10 mm , respectively . There was evidence of correlation between the x and y , x and z , and y and z axes in 3 , 3 , and 3 of 17 patients , respectively . Univariate ( ANOVA ) analysis showed that the total error pattern was r and om in the x , y , and z axis for 10 , 5 , and 2 of 17 patients , respectively , and systematic for the rest . Multivariate ( MANOVA ) analysis showed that the ( x , y ) , ( x , z ) , ( y , z ) , and ( x , y , z ) total error pattern was r and om in 5 , 1 , 1 , and 1 of 17 patients , respectively , and systematic for the rest . Conclusions The overall daily total error shift pattern for these 17 patients simulated with an empty bladder , and treated with CT on rails IGRT was predominantly systematic . Despite this , the temporal vector trends showed complex behaviors and unpredictable changes in magnitude and direction . These findings highlight the importance of using daily IGRT in post-prostatectomy patients The National Cancer Institute of Canada ( NCIC ) Clinical Trials Group PR.3/Medical Research Council PR07/ Intergroup T94 - 0110 ( 1 ) was a r and omized controlled trial ( RCT ) of radiation therapy ( RT ) and and rogen deprivation therapy ( ADT ) vs. ADT alone , for men with locally advanced prostate cancer . The authors defined locally advanced as : ( I ) T3 - 4 , N0/X , M0 ; or ( II ) T1 - 2 with prostate specific antigen ( PSA ) > 40 ng/mL ; or ( III ) PSA 20 - 40 ng/mL and Gleason 8 - 10 . Men were r and omized to lifelong ADT vs. ADT + RT , 65 - 69 Gy in 1.8 Gy fractions , using 3D conformal RT , to the prostate and pelvis or prostate alone . Of the 1,205 patients treated between 1995 and 2005 , 602 received ADT alone and 603 received ADT + RT .  Overall survival ( OS ) was significantly improved in the patients allocated to ADT + RT [ hazard ratio ( HR ) = 0.70 ; 95 % CI , 0.57 - 0.85 ; P<0.001 ] . Prostate cancer specific mortality ( CSM ) was improved in the patients allocated to ADT + RT ( HR = 0.46 ; 95 % CI , 0.34 - 0.61 ; P<0.001 ) . Although patients on ADT + RT arm reported a higher rate of gastrointestinal ( GI ) toxicity , only 2 of 589 patients had grade 3 or greater diarrhea at 24 months after RT Objectives : Freedom from biochemical failure ( FFBF ) is a common primary outcome of r and omized-controlled trials of prostate cancer ( PCa ) . We aim ed to determine how increasing the PCa biologically equivalent dose ( BED ) of external radiation therapy ( RT ) is correlated with FFBF and overall patient outcomes : overall survival ( OS ) , distant metastasis ( DM ) , and cancer-specific mortality ( CSM ) ; as well as genitourinary ( GU ) , and gastrointestinal toxicities . Material s and Methods : We performed a meta- analysis of 6884 PCa patients from 12 r and omized-controlled trials of external beam RT .  Mixed effects regression models were used to estimate weighted linear relationships between BED and observed percentages of 5- and 10-year outcomes . For toxicities , a subset analysis of using 3-dimensional conformal RT ( 3D-CRT ) versus intensity-modulated RT ( IMRT ) was performed . Results : Increasing BED correlated with improved FFBF : 10-year absolute improvement of 9.6 % and 7.2 % for low-risk and intermediate-risk patients , respectively ( P<0.05 ) ; but not with improvement of OS , DM , or CSM at either time point . BED escalation was not correlated with increased acute toxicities ; it was correlated with increased late gastrointestinal toxicities in patients treated with 3D-CRT  ( 1.5 % increase over BED range , P<0.01 ) . IMRT patients had significantly fewer late toxicities , despite being treated at higher BED . Conclusions : RT BED escalation has result ed in significantly improved PCa FFBF at up to 10 years ; but not with improvement in OS , DM , or CSM . Thus , FFBF is a poor surrogate of overall patient outcomes for trials of RT . Late toxicities were less frequent with IMRT than with 3D-CRT , even at higher BED Objectives : Stereotactic body radiation therapy ( SBRT ) takes advantage of the prostate ’s low α/β ratio to deliver a large radiation dose in few fractions . Initial studies on small groups of low-risk patients support SBRT ’s potential for clinical efficacy while limiting treatment-related morbidity and maintained quality of life . This prospect i ve study exp and s upon prior studies to further evaluate SBRT efficacy for a large patient population with organ confined , low- and intermediate-risk prostate cancer patients . Methods : Four hundred seventy-seven patients with prostate cancer received CyberKnife SBRT . The median age was 68.6 years and the median PSA was 5.3 ng/mL. Three hundred twenty-four patients were low-risk ( PSA < 10 ng/mL and Gleason < 7 ) , 153 were intermediate-risk ( PSA 10–20 ng/mL or Gleason = 7 ) . And rogen deprivation therapy was administered to 51 patients for up to 6 months . One hundred fifty-four patients received 35 Gy delivered in five daily fractions ; the remaining patients received a total dose of 36.25 Gy in five daily fractions . Biochemical failure was assessed using the phoenix criterion . Results : Median follow-up was 72 months . The median PSA at 7 years was 0.11 ng/mL. Biochemical failures occurred for 11 low-risk patients ( 2 locally ) , 14 intermediate-risk patients ( 3 locally ) . The actuarial 7-year freedom from biochemical failure was 95.6 and 89.6 % for low- and intermediate-risk groups , respectively ( p < 0.012 ) . Among patients with intermediate-risk disease , those considered to have low intermediate-risk ( Gleason 6 with PSA > 10 , or Gleason 3 + 4 with PSA < 10 ; n = 106 ) had a significantly higher bDFS than patients with high intermediate-risk ( Gleason 3 + 4 with PSA 10–20 or Gleason 4 + 3 ; n = 47 ) , with bDFS of 93.5 vs. 79.3 % , respectively . For the low-risk and low intermediate-risk groups , there was no difference in median PSA nadir or biochemical disease control between doses of 35 and 36.25 Gy . Conclusion : CyberKnife SBRT produces excellent biochemical control rates . Median PSA levels compare favorably with other radiation modalities and strongly suggest durability of response . These results also strongly suggest that 35 Gy is as effective as 36.25 Gy for low- and intermediate-risk patients PURPOSE Hypofractionated radiotherapy has an intrinsically different normal tissue and tumor radiobiology . The results of a prospect i ve trial of stereotactic body radiotherapy ( SBRT ) for prostate cancer with long-term patient-reported toxicity and tumor control rates are presented . METHODS AND MATERIAL S From 2003 through 2009 , 67 patients with clinical ly localized low-risk prostate cancer were enrolled . Treatment consisted of 36.25 Gy in 5 fractions using SBRT with the CyberKnife as the delivery technology . No patient received hormone therapy . Patient self-reported bladder and rectal toxicities were grade d on the Radiation Therapy Oncology Group scale ( RTOG ) . RESULTS Median follow-up was 2.7 years . There were no grade 4 toxicities . Radiation Therapy Oncology Group Grade 3 , 2 , and 1 bladder toxicities were seen in 3 % ( 2 patients ) , 5 % ( 3 patients ) , and 23 % ( 13 patients ) respectively . Dysuria exacerbated by urologic instrumentation accounted for both patients with Grade 3 toxicity . Urinary incontinence , complete obstruction , or persistent hematuria was not observed . Rectal Grade 3 , 2 , and 1 toxicities were seen in 0 , 2 % ( 1 patient ) , and 12.5 % ( 7 patients ) , respectively . Persistent rectal bleeding was not observed . Low- grade toxicities were substantially less frequent with QOD vs. QD dose regimen ( p = 0.001 for gastrointestinal and p = 0.007 for genitourinary ) . There were two prostate-specific antigen ( PSA ) , biopsy-proven failures with negative metastatic workup . Median PSA at follow-up was 0.5 ± 0.72 ng/mL. The 4-year Kaplan-Meier PSA relapse-free survival was 94 % ( 95 % confidence interval , 85%-102 % ) . CONCLUSION Significant late bladder and rectal toxicities from SBRT for prostate cancer are infrequent . PSA relapse-free survival compares favorably with other definitive treatments . The current evidence supports consideration of stereotactic body radiotherapy among the therapeutic options for localized prostate cancer PURPOSE Report of clinical cancer control outcomes on Radiation Therapy Oncology Group ( RTOG ) 9406 , a three-dimensional conformal radiation therapy ( 3D-CRT ) dose escalation trial for localized adenocarcinoma of the prostate . METHODS AND MATERIAL S RTOG 9406 is a Phase I/II multi-institutional dose escalation study of  3D-CRT for men with localized prostate cancer . Patients were registered on five sequential dose levels : 68.4 Gy , 73.8 Gy , 79.2 
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The data for SBRT show encouraging and comparable results in terms of freedom from biochemical failure ( > 90 % for low and intermediate risk at 5 - 7 years ) and acute and late toxicity ( < 6 % grade 3 - 4 late toxicities ) .
At this time , neither SBRT device is recommended over the other for all patients ; however , gantry-based SBRT machines have the abilities of treating larger volumes with conventional fractionation , shorter treatment time per fraction ( ~15 minutes for gantry vs ~45 minutes for robotic arm ) , and the ability to achieve better plans among obese patients ( since they are able to use energies > 6 MV ) .
Finally , SBRT ( particularly on a gantry ) may also be more cost-effective than conventionally fractionated external-beam radiation therapy .