***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 investigate the impact of xerostomia on overall quality of life ( QoL ) outcome and related dimensions among head and neck cancer patients treated with primary radiotherapy .  METHODS AND MATERIAL S A total of 288 patients with Stage I-IV disease without distant metastases were included .  Late xerostomia according to the Radiation Therapy Oncology Group ( RTOG-xerostomia ) and QoL ( European Organization for Research and Treatment of Cancer QLC-C30 ) were assessed at baseline and every 6th month from 6 months to 24 months after radiotherapy . RESULTS A significant association was found between RTOG-xerostomia and overall QoL outcome ( effect size [ ES ] 0.07 , p < 0.001 ) . A significant relationship with global QoL , all functioning scales , and fatigue and insomnia was observed . A significant interaction term was present between RTOG-xerostomia and gender and between RTOG-xerostomia and age . In terms of gender , RTOG-xerostomia had a larger impact on overall QoL outcome in women ( ES 0.13 for women vs. 0.07 for men ) . Furthermore , in women ES on individual scales were larger , and a marked worsening was observed with increasing RTOG-xerostomia . No different ES according to age was seen ( ES 0.10 for 18 - 65 years vs. 0.08 for > 65 years ) . An analysis of the impact of RTOG-xerostomia on overall QoL outcome over time showed an increase from 0.09 at 6 months to 0.22 at 24 months . With elapsing time , a worsening was found for these individual scales with increasing RTOG-xerostomia . CONCLUSIONS The results of this prospect i ve study are the first to show a significant impact of radiation-induced xerostomia on QoL. Although the incidence of Grade > or = 2 RTOG-xerostomia decreases with time , its impact on QoL increases . This finding emphasizes the importance of prevention of xerostomia PURPOSE Variations in target volume delineation represent a significant hurdle in clinical trials involving conformal radiotherapy . We sought to determine the effect of a consensus guideline -based visual atlas on contouring the target volumes . METHODS AND MATERIAL S A representative case was contoured ( Scan 1 ) by 14 physician observers and a reference expert with and without target volume delineation instructions derived from a proposed rectal cancer clinical trial involving conformal radiotherapy . The gross tumor volume ( GTV ) , and two clinical target volumes ( CTVA , including the internal iliac , presacral , and perirectal nodes , and CTVB , which included the external iliac nodes ) were contoured . The observers were r and omly assigned to receipt ( Group A ) or nonreceipt ( Group B ) of a consensus guideline and atlas for anorectal cancers and then instructed to recontour the same case/images ( Scan 2 ) . Observer variation was analyzed volumetrically using the conformation number ( CN , where CN = 1 equals total agreement ) . RESULTS Of 14 evaluable contour sets ( 1 expert and 7 Group A and 6 Group B observers ) , greater agreement was found for the GTV ( mean CN , 0.75 ) than for the CTVs ( mean CN , 0.46 - 0.65 ) . Atlas exposure for Group A led to significantly increased interobserver agreement for CTVA ( mean initial CN , 0.68 , after atlas use , 0.76 ; p = .03 ) and increased agreement with the expert reference ( initial mean CN , 0.58 ; after atlas use , 0.69 ; p = .02 ) . For the GTV and CTVB , neither the interobserver nor the expert agreement was altered after atlas exposure . CONCLUSION Consensus guideline atlas implementation result ed in a detectable difference in interobserver agreement and a greater approximation of expert volumes for the CTVA but not for the GTV or CTVB in the specified case . Visual atlas inclusion should be considered as a feature in future clinical trials incorporating conformal RT PURPOSE To compare directly the effect of intensity-modulated radiotherapy ( IMRT ) vs. conventional radiotherapy ( CRT ) on salivary flow and quality of life ( QoL ) in patients with early-stage nasopharyngeal carcinoma ( NPC ) . METHODS AND MATERIAL S Fifty-one patients with T2 , N0/N1 , M0 NPC took part in a r and omized controlled clinical study and received IMRT or CRT .  Stimulated whole ( SWS ) and parotid ( SPS ) saliva flow were measured and Medical Outcomes Short Form 36 ( SF-36 ) , European Organization for Research and Treatment of Cancer ( EORTC ) core quetionnaire , and EORTC head- and -neck module ( QLQ-H&N35 ) were completed at baseline and 2 , 6 , and 12 months after radiotherapy . RESULTS Forty-six patients ( 88 % ) were in disease remission 12 months after radiotherapy . At 12 months postradiotherapy , 12 ( 50.0 % ) and 20 patients ( 83.3 % ) in the IMRT group had recovered at least 25 % of preradiotherapy SWS and SPS flow respectively , compared with 1 ( 4.8 % ) and 2 patients ( 9.5 % ) , respectively , in the CRT group . Global health scores showed continuous improvement in QoL after both treatments ( p < 0.001 ) . However , after 12 months subscale scores for role-physical , bodily pain , and physical function were significantly higher in the IMRT group , indicating a better condition ( p < 0.05 ) . Dry mouth and sticky saliva were problems in both groups 2 months after treatment . In the IMRT group , there was consistent improvement over time with xerostomia-related symptoms significantly less common than in the CRT group at 12 months postradiotherapy . CONCLUSIONS IMRT was significantly better than CRT in terms of parotid sparing and improved QoL for early-stage disease . The findings support the case for assessment of health-related QoL in relation to head- and -neck cancer using a site-specific approach Summary Background Xerostomia is the most common late side-effect of radiotherapy to the head and neck . Compared with conventional radiotherapy , intensity-modulated radiotherapy ( IMRT ) can reduce irradiation of the parotid gl and s. We assessed the hypothesis that parotid-sparing IMRT reduces the incidence of severe xerostomia . Methods We undertook a r and omised controlled trial between Jan 21 , 2003 , and Dec 7 , 2007 , that compared conventional radiotherapy ( control ) with parotid-sparing IMRT . We r and omly assigned patients with histologically confirmed pharyngeal squamous-cell carcinoma ( T1–4 , N0–3 , M0 ) at six UK radiotherapy centres between the two radiotherapy techniques ( 1:1 ratio ) . A dose of 60 or 65 Gy was prescribed in 30 daily fractions given Monday to Friday . Treatment was not masked . R and omisation was by computer-generated permuted blocks and was stratified by centre and tumour site . Our primary endpoint was the proportion of patients with grade 2 or worse xerostomia at 12 months , as assessed by the Late Effects of Normal Tissue ( LENT SOMA ) scale . Analyses were done on an intention-to-treat basis , with all patients who had assessment s included . Long-term follow-up of patients is ongoing . This study is registered with the International St and ard R and omised Controlled Trial register , number IS RCT N48243537 . Findings 47 patients were assigned to each treatment arm . Median follow-up was 44·0 months ( IQR 30·0–59·7 ) . Six patients from each group died before 12 months and seven patients from the conventional radiotherapy and two from the IMRT group were not assessed at 12 months . At 12 months xerostomia side-effects were reported in 73 of 82 alive patients ; grade 2 or worse xerostomia at 12 months was significantly lower in the IMRT group than in the conventional radiotherapy group ( 25 [ 74 % ; 95 % CI 56–87 ] of 34 patients given conventional radiotherapy vs 15 [ 38 % ; 23–55 ] of 39 given IMRT , p=0·0027 ) . The only recorded acute adverse event of grade 2 or worse that differed significantly between the treatment groups was fatigue , which was more prevalent in the IMRT group ( 18 [ 41 % ; 99 % CI 23–61 ] of 44 patients given conventional radiotherapy vs 35 [ 74 % ; 55–89 ] of 47 given IMRT , p=0·0015 ) . At 24 months , grade 2 or worse xerostomia was significantly less common with IMRT than with conventional radiotherapy ( 20 [ 83 % ; 95 % CI 63–95 ] of 24 patients given conventional radiotherapy vs nine [ 29 % ; 14–48 ] of 31 given IMRT ; p<0·0001 ) . At 12 and 24 months , significant benefits were seen in recovery of saliva secretion  with IMRT compared with conventional radiotherapy , as were clinical ly significant improvements in dry-mouth-specific and global quality of life scores . At 24 months , no significant differences were seen between r and omised groups in non-xerostomia late toxicities , locoregional control , or overall survival . Interpretation Sparing the parotid gl and s with IMRT significantly reduces the incidence of xerostomia and leads to recovery of saliva secretion and improvements in associated quality of life , and thus strongly supports a role for IMRT in squamous-cell carcinoma of the head and neck . Funding Cancer Research UK ( CRUK/03/005 ) PURPOSE Three-dimensional ( 3D ) conformal radiation therapy ( CRT ) assumes and requires the precise delineation of the target volume . To assess the consistency of target volume delineation by radiation oncologists , who treat esophageal cancers , we have performed a transCanada survey . MATERIAL S AND METHODS One of three case presentations , including CT scan images , of different stages of cervical esophageal cancer was r and omly chosen and sent by mail . Respondents were asked to fill in question naires regarding treatment techniques and to outline boost target volumes for the primary tumor on CT scans , using ICRU-50 definitions . RESULTS Of 58 radiation oncologists who agreed to participate , 48 ( 83 % ) responded . The external beam techniques used were mostly anterior-posterior fields , followed by a multifield boost technique . Brachytherapy was employed by 21 % of the oncologists , and concurrent chemotherapy by 88 % . For a given case , and the three volumes defined by ICRU-50 ( i.e. , gross tumor volume [ GTV ] , clinical target volume [ CTV ] , and planning target volume [ PTV ] ) we determined : 1 . The total length in the cranio-caudal dimension ; 2 . the mean diameter in the transverse slice that was located in a CT slice that was common to all participants ; 3 . the total volume for each ICRU volume ; and 4 . the ( 5 , 95 ) percentiles for each parameter . The PTV showed a mean length of 14.4 ( 9.6 , 18.0 ) cm for Case A , 9.4 ( 5.0 , 15.0 ) cm for Case B , 11.8 ( 6.0 , 16.0 ) cm for Case C , a mean diameter of 6.4 ( 5.0 , 9.4 ) cm for Case A , 4.4 ( 0.0 , 7.3 ) cm for Case B , 5.2 ( 3.9 , 7.3 ) cm for Case C , and a mean volume of 320 ( 167 , 840 ) cm3 for Case A and 176 ( 60 , 362 ) cm3 for Case C. The results indicate variability factors ( 95 percentile divided by 5 percentile values ) in target diameters of 1.5 to 2.6 , and in target lengths of 1.9 to 5.0 . CONCLUSION There was a substantial inconsistency in defining the planning target volume , both transversely and longitudinally , among radiation oncologists . The potential benefits of 3D treatment planning with high-precision dose delivery could be offset by this inconsistency in target-volume delineation by radiation oncologists . This may be particularly important for multicenter clinical trials , for which quality assurance of this step will be essential to the interpretation of results PURPOSE To compare quality of life ( QOL ) and xerostomia between head- and -neck cancer patients who received st and ard radiotherapy ( RT ) and patients matched by factors known to affect QOL who received intensity-modulated RT ( IMRT ) .  METHODS AND MATERIAL S This was a prospect i ve , longitudinal study of patients with head- and -neck cancer requiring bilateral neck irradiation who received IMRT at the University of Michigan and patients who received st and ard RT at affiliated clinics . Each patient received a vali date d head- and -neck cancer-related QOL question naire ( HNQOL ) consisting of four multi-item domains -- Eating , Communication , Pain , and Emotion-- and a vali date d patient-reported  xerostomia question  naire ( XQ ) . In both question naires , the answers were scored 0 - 100 , with higher scores denoting worse QOL or xerostomia . The question naires were given before therapy and at 1 , 3 , 6 , 12 , 18 , 
    Output:
    
Interobserver variation in parotid gl and delineation is significant .