***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: Results : Proportions of patients retaining  visual acuity of at least 20/200 were similar in the 2 dose groups at 5 years after radiation ( approximately 55 % ) . Similar numbers of patients in each group experienced tumor regrowth ( 2 patients at 50 CGE vs 3 patients at 70 CGE ; P .. 99 ) and metastasis ( 7 patients at 50 CGE vs 8 patients at 70 CGE ; P=.79 ) . Five-year rates of radiation maculopathy also were similar ( for both groups , approximately 75 % for tumors within 1 disc diameter and 40 % for tumors .1 disc diameter from the macula ) . Rates of radiation papillopathy were nonsignificantly decreased in the 50-CGE treatment group when tumors were located 1 disc diameter or less from the optic disc ( P=.20 ) . Patients treated with the lower dose also experienced significantly less visual field loss To the Editor : This opposing views article highlights some of the fundamental differences in how radiation oncologists view the burgeoning ( but not new ) application of proton beam therapy ( PBT ) to treat prostate cancer . Hoppe et al articulate the respective arguments of the so-called proton and photon “ camps ” that have emerged within our specialty . These camps predictably fall along the lines of whether one practice s at a center with PBT , and the financial differences between the 2 technologies are the key driver of the debate . Frankly none of us would be arguing against a product or device that delivers less unwanted radiation while maintaining ( if not increasing ) dose to the targetdif the cost is comparable to the alternatives . But it is different with prostate cancer . Excellent and affordable alternatives do exist , including brachytherapy , which is cheaper and more conformal than PBT and intensity modulated radiation therapy ( IMRT ) . Those who use PBT should ask the important clinical questions , test them , and be given the time and re sources to do so . Those who use only photon based techniques should , in turn , support these efforts , recognizing that IMRT was not held to the same st and ard when it was widely adopted over older and cheaper conventional techniques . Rather than recapitulating conflicting interpretations of the same method ologically flawed study , 1,2 as is done here , the radiation oncology community could look to patient level data on prospect ively collected toxicity and quality of life outcomes for a disease as prevalent as prostate cancer . 3 In the spirit of incorporating patient reported outcomes Hoppe and Bryant suggest that the retrospectively observed 6 % to 8 % difference in bowel quality of life as measured by EPIC ( Exp and ed Prostate Cancer Index Composite ) is not only statistically significant , but also clinical ly relevant . 4 S and ler references the currently open r and omized trial of IMRT vs proton therapy in prostate cancer , which has a primary end point of 2-year patient reported bowel quality of life ( using EPIC ) . While this study will examine whether the retrospectively observed difference in bowel quality of life is statistically significant in a phase III setting , will it answer the question of whether it is clinical ly meaningful ? If we do not see a difference for this specific end point , the trial will be negative . But will we truly feel that we answered the question of which is better ? The media and payers certainly will , and frankly in many cases they have already decided that cheaper is better , period . The tide against PBT due to its generally greater costs is a foregone conclusion in many parts of the country but we have not afforded it the opportunity to prove itself . The institutional studies that have been reported to date generally all used passive scatter technique , an increasingly out date d and suboptimal form of proton beam delivery . We need to compare the “ best ” PBT techniques ( ie pencil beam scanning ) to the best IMRT . This comparison will require patience as centers work to responsibly deploy such capabilities . 5 While time is a rare luxury in the world of “ do more with less , ” it is necessary if we really want to test the various hypotheses described by the authors . Although there is multidirectional pressure to produce and report trial results quickly , doing so in prostate cancer can give a limited view of a disease with a long natural history involving patients who are at risk for late toxicities and relapses . As S and ler notes , the proton debate in prostate cancer carries great economic importance . But the comparative effectiveness challenges inherent to prostate cancer hopefully will not translate to a general disregard of PBT for other cancers . As a genitourinary radiation oncologist who uses PBT and photon based IMRT , I would like us to focus our efforts on investigating the promise BACKGROUND Owing to its physical properties , intensity-modulated proton therapy ( IMPT ) used for patients with oropharyngeal carcinoma has the ability to reduce the dose to organs at risk compared to intensity-modulated radiotherapy ( IMRT ) while maintaining adequate tumor coverage . Our aim was to compare the clinical outcomes of these two treatment modalities . METHODS We performed a 1:2 matching of IMPT to IMRT patients . Our study cohort consisted of  IMPT patients from a prospect i ve quality of life study and consecutive IMRT patients treated at a single institution during the period 2010 - 2014 . Patients were matched on unilateral/bilateral treatment , disease site , human papillomavirus status , T and N status , smoking status , and receipt of concomitant chemotherapy .  Survival analyzes were performed using a Cox model and binary toxicity endpoints using a logistic regression analysis . RESULTS Fifty IMPT and 100 IMRT patients were included . The median follow-up time was 32months . There were no imbalances in patient/tumor characteristics except for age ( mean age 56.8years for IMRT patients and 61.1years for IMPT patients , p-value=0.010 ) . Statistically significant differences were not observed in overall survival ( hazard ratio (HR)=0.55 ; 95 % confidence interval ( CI ) : 0.12 - 2.50 , p-value=0.44 ) or in progression-free survival ( HR=1.02 ; 95 % CI : 0.41 - 2.54 ; p-value=0.96 ) . The age-adjusted odds ratio ( OR ) for the presence of a gastrostomy (G)-tube during treatment for IMPT vs IMRT were OR=0.53 ; 95 % CI : 0.24 - 1.15 ; p-value=0.11 and OR=0.43 ; 95 % CI : 0.16 - 1.17 ; p-value=0.10 at 3months after treatment . When considering the pre-planned composite endpoint of grade 3 weight loss or G-tube presence , the ORs were OR=0.44 ; 95 % CI : 0.19 - 1.0 ; p-value=0.05 at 3months after treatment and OR=0.23 ; 95 % CI : 0.07 - 0.73 ; p-value=0.01 at 1year after treatment . CONCLUSION Our results suggest that IMPT is associated with reduced rates of feeding tube dependency and severe weight loss without jeopardizing outcome . Prospect i ve multicenter r and omized trials are needed to vali date such findings PURPOSE We determined the long-term normal tissue effects of 77.4 Gy . delivered to the prostate in patients with locally advanced prostate cancer . METHODS AND MATERIAL S Between 1976 and 1992 , 167 men with stages T3 to 4 prostate cancer were treated on protocol with 50.4 Gy . photons at 1.8 Gy . per fraction using a 4-field box arrangement , followed by a conformal perineal proton boost of 27 Gy . ( cobalt Gy . equivalent ) in 11 fractions . The chart was review ed and 39 of the 42 surviving patients were interviewed . Median followup was 13.1 years ( range 7 to 23 ) . Normal tissue morbidity was recorded using Radiation Therapy Oncology Group criteria and the late effects normal tissue scale . RESULTS The actuarial incidence of grade 2 or greater genitourinary morbidity was 59 % at 15 years . However , these grade 2 or greater problems persisted to the time of the interview in only 7 of 39 cases . The actuarial incidence of grade 2 or greater hematuria was 21 % at 5 years and 47 % at 15 . For grade 3 or greater hematuria the risk was 3 % and 8 % at 5 and 15 years , respectively . No patient required cystectomy but 1 required diversion for morbidity . Urethral stricture and urinary incontinence with pads needed developed in 4 and 3 men , respectively . This particular morbidity was strongly associated with previous or subsequent prostate surgery . The actuarial incidence of grade 2 or greater gastrointestinal morbidity was 13 % at 5 and 15 years , while grade 1 rectal bleeding occurred in another 41 % . CONCLUSIONS High dose conformal radiation to the prostate is followed by a high rate of low grade rectal bleeding but a low rate of grade 2 or higher gastrointestinal morbidity . This rate is stable and does not increase beyond 5 years . Genitourinary morbidity continues to develop well into the second decade after treatment , although high grade morbidity is uncommon . These findings do not suggest that the modern trend toward high dose prostate treatment with conformal techniques will result in a high incidence of serious and permanent late sequelae but it appears that hematuria will be common We describe a framework for defining  pilot and feasibility studies  focusing on studies conducted in preparation for a r and omised controlled trial . To develop the framework , we undertook a Delphi survey ; ran an open meeting at a trial methodology conference ; conducted a review of definitions outside the health research context ; consulted experts at an international consensus meeting ; and review ed 27 empirical pilot or feasibility studies . We initially adopted mutually exclusive definitions of pilot and feasibility studies . However , some Delphi survey respondents and the majority of open meeting attendees disagreed with the idea of mutually exclusive definitions . Their viewpoint was supported by definitions outside the health research context , the use of the terms ‘ pilot ’ and ‘ feasibility ’ in the literature , and participants at the international consensus meeting . In our framework , pilot studies are a subset of feasibility studies , rather than the two being mutually exclusive . A feasibility study asks whether something can be done , should we proceed with it , and if so , how . A pilot study asks the same questions but also has a specific design feature : in a pilot study a future study , or part of a future study , is conducted on a smaller scale . We suggest that to facilitate their identification , these studies should be clearly identified using the terms ‘ feasibility ’ or ‘ pilot ’ as appropriate . This should include feasibility studies that are largely qualitative ; we found these difficult to identify in electronic search es because research ers rarely used the term ‘ feasibility ’ in the title or abstract of such studies . Investigators should also report appropriate objectives and methods related to feasibility ; and give clear confirmation that their study is in preparation for a future r and omised controlled trial design ed to assess the effect of an intervention PURPOSE Several r and omized trials have shown a benefit of dose escalation to 78 to 79 Gy for men treated with external radiation for localized prostate cancer . Single-institution data suggest a benefit with even higher doses . American College of Radiology 03 - 12 is a Phase II trial testing the safety and efficacy of 82 GyE ( Gray equivalent ) delivered with conformal proton radiation . METHODS AND MATERIAL S From 2003 - 2006 , 85 men with localized prostate cancer were accrued to American College of Radiology 03 - 12 . Eighty-four were eligible for analysis . They were treated with conformal proton radiation alone to a total dose of 82 GyE. The study was design ed to test whether the rate of 18-month Grade 3 + late toxicity was greater than 10 % . RESULTS The median follow-up was 31.6 months . Regarding treatment-related acute toxicity , there were 39 Grade 1 cases ( 46 % ) , 19 Grade 2 cases ( 23 % ) and 2 Grade 3 cases ( 2 % ) . Regarding genitourinary/gastrointestinal toxicity , there were 42 Grade 1 cases ( 50 % ) , 12 Grade 2 cases ( 14 % ) and 1 Grade 3 case ( 1 % ) . Regarding late toxicity , there were 28 Grade 1 cases ( 33 % ) , 22 Grade 2 cases ( 26 % ) , 6 Grade 3 cases ( 7 % ) , and 1 Grade 4 case ( 1 % ) . The late genitourinary/gastrointestinal rates were the same . The estimated rate of Grade 3 + late toxicity at 18 months was 6.08 % . CONCLUSIONS Although not free of late toxicity , 82 GyE at 2 GyE per fraction delivered with conformal proton radiation did not exceed the late morbidity target tested in this trial . There was sufficient morbidity , however , that this may be the maximal dose that can be delivered safely with this technique and fractionation CONTEXT Increased radiation doses improve prostate cancer control but also increase toxicity to adjacent normal tissue . Proton radiation may attenuate adverse effects . OBJECTIVE To determine long-term , patient-reported , dose-related toxicity . DESIGN , SETTING , AND PATIENTS We performed a post hoc cross-sectional survey of surviving participants in the Proton Radiation Oncology Group ( PROG ) 9509 - -a r and omized trial comparing 70.2 Gy vs 79.2 Gy of combined photon and proton radiation for 393 men with clinical ly localized prostate cancer ( stage T1b-T2b , prostate-specific antigen < 15 ng/mL , and no radiographic evidence of metastasis ) . The estimated 10-year biochemical progression rate for patients receiving st and ard do 
    Output:
    
Highlights • Less than half of published clinical studies of proton beam therapy are prospect ive.• Only 10 % of prospect i ve studies of proton beam therapy are r and omised.• Toxicity is the most common primary endpoint of interventional studies