***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 identify dosimetric parameters derived from anorectal , rectal , and anal wall dose distributions that correlate with different late gastrointestinal ( GI ) complications after  three-dimensional conformal radiotherapy for prostate cancer . METHODS AND MATERIAL S In this analysis , 641 patients from a r and omized trial ( 68 Gy vs. 78 Gy ) were included . Toxicity was scored with adapted Radiation Therapy Oncology Group/European Organization for the Research and Treatment of Cancer ( RTOG/EORTC ) criteria and five specific complications . The variables derived from dose-volume histogram of anorectal , rectal , and anal wall were as follows : % receiving > or = 5 - 70 Gy ( V5-V70 ) , maximum dose ( Dmax ) , and mean dose ( D(mean ) ) . The anus was defined as the most caudal 3 cm of the anorectum . Statistics were done with multivariate Cox regression models . Median follow-up was 44 months . RESULTS Anal dosimetric variables were associated with RTOG/EORTC Grade > or = 2 ( V5-V40 , D(mean ) ) and incontinence ( V5-V70 , D(mean ) ) . Bleeding correlated most strongly with anorectal V55-V65 , and stool frequency with anorectal V40 and D(mean ) . Use of steroids was weakly related to anal variables . No volume effect was seen for RTOG/EORTC Grade > or =3 and pain/cramps/tenesmus . CONCLUSION Different volume effects were found for various late GI complications . Therefore , to evaluate the risk of late GI toxicity , not only intermediate and high doses to the anorectal wall volume should be taken into account , but also the dose to the anal wall AIMS Increases to radiotherapy dose are constrained by normal tissue effects . The relationship between bowel dose volume data and late bowel toxicity in patients with muscle-invasive bladder cancer treated with radical radiotherapy  was assessed . MATERIAL S AND METHODS The bowel was contoured retrospectively on radiotherapy plans of 47 patients recruited to the BC2001 trial ( CRUK/01/004 ) . The relationship between bowel volume at various dose levels and prospect ively collected late bowel toxicity was explored . RESULTS Fifteen per cent and 6 % of patients experienced grade 1 and grade 2 or more late bowel toxicity , respectively . The mean bowel volume was significantly less at doses ≥50 Gy in those treated with reduced high dose volume radiotherapy compared with st and ard radiotherapy .  The probability of late bowel toxicity increased as bowel volume increased ( P ≤ 0.05 for dose levels 30 - 50 Gy ) . No grade 2 or more late bowel toxicity was observed in patients with bowel volumes under the thresholds given in the model that predict for 25 % probability of late bowel toxicity . CONCLUSIONS There is a dose volume effect for late bowel toxicity in radical bladder radiotherapy . We have modelled the probability of late bowel toxicity from absolute bowel volumes to guide clinicians in assessing radical bladder radiotherapy plans . Thresholds predicting for a 25 % probability of late bowel toxicity are proposed as dose volume constraints PURPOSE Toxicity concerns have limited pelvic nodal prescriptions to doses that may be suboptimal for controlling microscopic disease . In a prospect i ve trial , we tested whether image-guided intensity-modulated radiation therapy ( IMRT ) can safely deliver escalated nodal doses while treating the prostate with hypofractionated radiotherapy in 5½ weeks . METHODS AND MATERIAL S Pelvic nodal and prostatic image-guided IMRT was delivered to 53 National Comprehensive Cancer Network ( NCCN ) high-risk patients to a nodal dose of 56 Gy in 2-Gy fractions with concomitant treatment of the prostate to 70 Gy in 28 fractions of 2.5 Gy , and 50 of 53 patients received and rogen deprivation for a median duration of 12 months . RESULTS The median follow-up time was 25.4 months ( range , 4.2 - 57.2 ) . No early Grade 3 Radiation Therapy Oncology Group or Common Terminology Criteria for Adverse Events v.3.0 genitourinary ( GU ) or gastrointestinal ( GI ) toxicities were seen . The cumulative actuarial incidence of Grade 2 early GU toxicity ( primarily alpha blocker initiation ) was 38 % . The rate was 32 % for Grade 2 early GI toxicity . None of the dose-volume descriptors correlated with GU toxicity , and only the volume of bowel receiving ≥30 Gy correlated with early GI toxicity ( p = 0.029 ) . Maximum late Grade s 1 , 2 , and 3 GU toxicities were seen in 30 % , 25 % , and 2 % of patients , respectively . Maximum late Grade s 1 and 2 GI toxicities were seen in 30 % and 8 % ( rectal bleeding requiring cautery ) of patients , respectively . The estimated 3-year biochemical control ( nadir + 2 ) was 81.2 ± 6.6 % . No patient manifested pelvic nodal failure , whereas 2 experienced paraaortic nodal failure outside the field . The six other clinical failures were distant only . CONCLUSIONS Pelvic IMRT nodal dose escalation to 56 Gy was delivered concurrently with 70 Gy of hypofractionated prostate radiotherapy in a convenient , re source -efficient , and well-tolerated 28-fraction schedule . Pelvic nodal dose escalation may be an option in any future exploration of potential benefits of pelvic radiation therapy in high-risk prostate cancer patients AIMS About 17,000 patients receive radiotherapy for pelvic cancer in the UK annually . Up to 50 % are left with altered bowel function affecting quality of life . The UK National Cancer Survivorship Initiative Vision acknowledges that the needs of cancer survivors are not being met and challenges professionals to develop new models of care . MATERIAL S AND METHODS A prospect i ve , observational qualitative study was carried out to assess whether nurse-delivered care is feasible for patients with radiotherapy-induced bowel dysfunction .  The experience of a senior nurse , directed by an algorithm of investigation with a comprehensive treatment pathway , is reported . RESULTS Over 12 months , 59 new and 103 follow-up appointments were managed by the nurse . In total , 37 women and 73 men , with a median age of 69 years , were seen ; 9 had been treated for gastrointestinal , 33 for gynaecological and 68 for urological cancers , 26 months ( median ) previously . Sixty minutes ( new consultations ) ( median , range 35 - 80 ) and 40 minutes ( follow-up consultations ) ( range 20 - 85 ) were required . Ordering investigations , treatment initiation , long-term care planning and discharge seemed to be manageable in 83 % of patients . CONCLUSION An experienced nurse , working within a defined scope of practice , with medical support can manage care in patients with mild or moderate symptoms arising after pelvic radiotherapy . An ongoing r and omised controlled trial is assessing patient outcomes BACKGROUND AND PURPOSE The late morbidity of a r and omized study was analyzed after a follow up of 2 years . The difference in intestinal morbidity was analyzed as a function of the treatment arm and dose volume parameters . The correlation with acute toxicity and ( pre-existing ) bowel complaints was investigated . PATIENTS AND METHODS 266 T1 - 4N0M0 prostate cancer patients were r and omized for conventional ( open fields ) and 3D conformal radiotherapy using beams eye view blocked fields with the same dose ( 66 Gy ) and gross target volume-planning target volume margin ( 15 mm ) . Apart from the RTOG toxicity scoring system a patient self- assessment question naire was used to obtain detailed information on morbidity . RESULTS At 2 years there is only a trend for less rectal toxicity ( grade > /=1 ) in favor of the conformal radiotherapy ( grade 1 , 47 versus 40 % and grade 2 , 10 versus 7 % for conventional and conformal radiotherapy , respectively ( P=0.1 ) . A significant relation was found between late rectal toxicity ( grade > /=1 ) and the volume of the anus and rectum exposed to > /=90 % tumor dose ( TD ) . A highly significant relationship is observed between acute rectum and anal toxicity and late rectal toxicity . The patient self- assessment question naire analysis revealed that patients are most bothered by compliance related symptoms like urgency , soiling and fecal loss . In a multivariate analysis , all other variables loose significance , when anal volume exposed to > /=90 % TD and pre-treatment defaecation frequency are accounted for . Late anal toxicity is low and related only to acute anal toxicity . Late bladder toxicity is related solely to pre-treatment frequency and overall urological symptoms . The incidence of grade 2 toxicity increases with a factor 2.5 - 4 when ( stool or urine ) frequency is unfavorable at the start of treatment . CONCLUSIONS Conformal radiotherapy at the dose level of 66 Gy does not significantly decrease the incidence of rectal , anal and bladder toxicity compared to conventional radiotherapy . There is a significant relationship between acute and late toxicity and the anal volume exposed to 90 % TD . Intestinal ( and urological ) symptoms at start have a major impact on late toxicity Abstract Background Chronic gastrointestinal ( GI ) morbidity occurs in ≥50 % of patients after external beam radiotherapy ( EBRT ) for carcinoma of prostate ( CaP ) . This prospect i ve , longitudinal study examines which baseline measurements of : 1 ) homocysteine and micronutrients in plasma ; 2 ) chromosome damage/misrepair biomarkers ; and 3 ) anal and rectal dose volume metrics predict GI morbidity after EBRT . Patients and methods In total , 106 patients with CaP had evaluations of GI symptoms ( modified LENT-SOMA question naires ) before EBRT  and at one month , one , two and three years after its completion . Other variables measured before EBRT were : 1 ) plasma concentrations of homocysteine and micronutrients including caroteinoids and selenium ; 2 ) chromosome damage/DNA misrepair ( micronuclei/nucleoplasmic bridge ) indices ; and 3 ) mean anal and rectal wall doses and volumes of anal and rectal walls receiving ≥40 Gy and ≥60 Gy . Univariate and multivariate analyzes examined the relationships among : 1 ) plasma levels of homocysteine and micronutrients ; 2 ) indices of chromosome damage/DNA misrepair ; and 3 ) mean anal and rectal wall doses and volumes of anal and rectal walls receiving ≥40 Gy and ≥60 Gy and total GI symptom scores from one month to three years after EBRT . Results Increased frequency and urgency of defecation , rectal mucous discharge and bleeding after EBRT result ed in sustained rises in total GI symptom scores above baseline at three years . On univariate analysis , total GI symptom scores were significantly associated with : 1 ) plasma selenium and α tocopherol ; 2 ) micronuclei indices of DNA damage ; 3 ) mean anal and rectal wall doses ; and 4 ) volumes of anal and rectal wall receiving ≥40 Gy and ≥60 Gy ( p = 0.08–<0.001 ) . On multivariate analysis , only volume of anal wall receiving ≥40 Gy was significant for increased GI symptoms after EBRT ( p < 0.001 ) . Conclusion The volume of anal wall receiving ≥40 Gy predicts chronic GI morbidity after EBRT for PURPOSE To report on : 1 . Late radiotherapy-induced lower intestinal toxicity ( RILIT ) after intensity-modulated radiotherapy ( IMRT ) for prostate cancer . 2 . The correlation between late RILIT and volume parameters of the rectum , sigmoid colon and small bowel . MATERIAL S AND METHODS We included 241 patients with a follow-up of > or=18 months for this analysis . Late RILIT consisted of 8 different symptoms , comprising the 5 symptoms from the RTOG toxicity score supplemented with urgency , fecal incontinence and anal pain . Late RILIT and late RTOG toxicity were scored prospect ively and correlated with : 1 . Different rectum , sigmoid colon and small bowel volume parameters . 2 . Patient-related morbidity . We calculated the median , quartile and percentiles for the different volume parameters and correlated them with grade 1 - 3 late RILIT . RESULTS Median follow-up was 42 months . Three patients developed grade 3 red blood loss . We registered grade 2 RILIT and RTOG toxicity in 13 % and 10 % , respectively , the most frequent grade 1 symptom being fecal urgency . The intermediate rectal volume parameters were significantly correlated with late RILIT . We were able to calculate cut-off dose-volume histograms ( DVHs ) that predict for grade 0 - 2 RILIT . CONCLUSIONS After IMRT for prostate cancer , the overall incidence of grade > or=2 RILIT is low . Cut-off DVHs can be used for patient counseling PURPOSE To analyze whether inclusion of predisposing clinical features in the Lyman-Kutcher-Burman ( LKB ) normal tissue complication probability ( NTCP 
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Conclusions The anal canal is an important OAR for the development of late bowel toxicity symptoms .