***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: Objectives :  Clinical benefit response ( CBR )  , based on changes in pain , Karnofsky performance status , and weight , is an established palliative endpoint in trials for advanced gastrointestinal cancer . We investigated whether CBR is associated with survival , and whether CBR reflects a wide-enough range of domains to adequately capture patients ' perception . Methods : CBR was prospect ively evaluated in an international phase III chemotherapy trial in patients with advanced pancreatic cancer ( n = 311 ) in parallel with patient-reported outcomes ( PROs ) . Results : The median time to treatment failure was 3.4 months ( range : 0 - 6 ) . The majority of the  CBRs  ( n = 39 ) were noted in patients who received chemotherapy for at least 5 months . Patients with CBR ( n = 62 ) had longer survival than non-responders ( n = 182 ) ( hazard ratio = 0.69 ; 95 % confidence interval : 0.51 - 0.94 ; p = 0.013 ) . CBR was predicted with a sensitivity and specificity of 77 - 80 % by various combinations of 3 mainly physical PROs . A comparison between the duration of CBR  ( n = 62 , median = 8 months , range = 4 - 31 ) and clinical ly meaningful improvements in the PROs ( n = 100 - 116 ; medians = 9 - 11 months , range = 4 - 24 ) showed similar intervals . Conclusion : CBR is associated with survival and mainly reflects physical domains . Within phase III chemotherapy trials for advanced gastrointestinal cancer , CBR can be replaced by a PRO evaluation , without losing substantial information but gaining complementary information BACKGROUND AND OBJECTIVE CybeKnife is a newly developed technology in the field of stereotactic radiosurgery/radiotherapy ( SRS/SRT ) . Compared with conventional SRS/SRT , there are many advantages for CyberKnife in terms of treating tumors that move with respiration , being real-time image-guidance , frameless , high accurateness , and so on . Recently , it has been used to treat different types of malignant carcinoma including intracranial and caudomedial tumors . This study was design ed to evaluate the short-term efficacy and toxicity of the CyberKnife radiotherapy for locally advanced pancreatic cancer . METHODS A total of 20 patients with locally advanced ( stage II-III ) pancreatic cancer treated with CyberKnife were recruited between April 2009 and December 2009 . Of 20 patients , 13 were with cancer located at the pancreatic head and 7 were located at the pancreatic body and tail . The planning target volume ( PTV ) was defined as gross tumor volume ( GTV ) plus 2 - 3 mm , and more than 95 % PTV should be covered by 75 % isodose surface . The median of PTV was 47 cm³ ( 26 - 64 cm³ ) . The median total prescription dose was 40 Gy ( 32 - 55 Gy ) at 3 - 6 fractions . During treatment delivery , X-Sight Spine Tracking System was used in 5 patients to track movement of the tumor . Other 15 patients were implanted fiducials in the tumors to track movement of the tumor and patient breathing patterns . RESULTS The median follow-up time was 7 months ( 3 - 11 months ) . All patients had finished the treatment and 19 were alive by the last follow-up . Slight fatigue was the most common complain . Evaluated by CT scan , 6 were complete response , 9 were partial response , 3 were stable disease , and 1 was progression ; 1 was dead . There were 6 patients with grade I granulocytopenia , 7 with grade I nausea , and 5 with grade II vomiting . CONCLUSIONS The CyberKnife radiosurgery for the locally advanced pancreatic cancer shows a high rate of local control and minimal toxicity . Long-term follow-up is necessary to evaluate the survival and late toxicity Background Pancreatic cancer accounts for approximately 3 % of cancer deaths in Europe . Locally advanced pancreatic cancer ( LAPC ) involves vascular structures , and resectability is low , with a median survival time of 6 to 11 months . We conducted a prospect i ve , nonr and omized study of patients with LAPC to assess the effect of stereotactic body radiotherapy ( SBRT ) on local response , pain control , and quality of life ( QOL ) . Methods Twenty-three patients with histologically confirmed LAPC underwent SBRT . Radiotherapy ( 30 Gy ) was delivered in three fractions , and treatment toxicity was assessed according to the Common Terminology Criteria for Adverse Events ( CTCAE v. 3.0 ) . All patients received also gemcitabine chemotherapy and were followed up until death . Local control was assessed according to Response Evaluation Criteria in Solid Tumors ( RECIST ) criteria , pain control was assessed with a visual analog scale , and QOL was assessed with the SF-36 instrument ( Italian v. 1.6 ) . Results No grade 2 or higher acute or late toxicity was observed . The overall local response ratio was 82.6 % ( 14 partial response , 2 complete response , 3 stable disease ) . SBRT showed a good short-term efficacy in controlling both pain and QOL . Median survival was 10.6 months , with a median follow-up of 9 months . The LAPC became resectable in 8 % of the patients . Median time to progression of disease was 7.3 months . Six patients developed early metastatic disease . Conclusions The SBRT method is a promising treatment for LAPC . Local control rates , even compared to historical data from conventional radiotherapy , can be achieved with minimal toxicity . Resectability can also be achieved This phase 2 multi‐institutional study was design ed to determine whether gemcitabine ( GEM ) with fractionated stereotactic body radiotherapy ( SBRT ) results in acceptable late grade 2 to 4 gastrointestinal toxicity when compared with a prior trial of GEM with single‐fraction SBRT in patients with locally advanced pancreatic cancer ( LAPC ) PURPOSE The purpose of this trial was to evaluate the role of radiation therapy with concurrent gemcitabine ( GEM ) compared with GEM alone in patients with localized unresectable pancreatic cancer . PATIENTS AND METHODS Patients with localized unresectable adenocarcinoma of the pancreas were r and omly assigned to receive GEM alone ( at 1,000 mg/m(2)/wk for weeks 1 to 6 , followed by 1 week rest , then for 3 of 4 weeks ) or GEM ( 600 mg/m(2)/wk for weeks 1 to 5 , then 4 weeks later 1,000 mg/m(2 ) for 3 of 4 weeks ) plus radiotherapy ( starting on day 1 , 1.8 Gy/Fx for total of 50.4 Gy ) . Measurement of quality of life using the Functional Assessment of Cancer Therapy-Hepatobiliary question naire was also performed . RESULTS Of 74 patients entered on trial and r and omly assigned to receive GEM alone ( arm A ; n = 37 ) or GEM plus radiation ( arm B ; n = 34 ) , patients in arm B had greater incidence of grade s 4 and 5 toxicities ( 41 % v 9 % ) , but grade s 3 and 4 toxicities combined were similar ( 77 % in A v 79 % in B ) . No statistical differences were seen in quality of life measurements at 6 , 15 to 16 , and 36 weeks . The primary end point was survival , which was 9.2 months ( 95 % CI , 7.9 to 11.4 months ) and 11.1 months ( 95 % CI , 7.6 to 15.5 months ) for arms A and B , respectively ( one-sided P = .017 by stratified log-rank test ) . CONCLUSION This trial demonstrates improved overall survival with the addition of radiation therapy to GEM in patients with localized unresectable pancreatic cancer , with acceptable toxicity Aim : To analyze the results of extracranial stereotactic radiotherapy ( ESRT )  experience in pancreatic cancer patients . Methods : Four noncoplanar fixed beams were used in all patients . Results : Analysis of 16 patients was carried out . Overall response rate was 56.2 % . Fifteen patients experienced local and /or distant progression of disease ( median follow-up : 24 months ) . Two-year local progression-free , distant progression-free , and overall survivals were 85.7 % , 58.7 % , and 50.0 % , respectively . Toxicity was less than grade 2 in all , although 1 patient had severe duodenal bleeding . Quality of life scores were unchanged . Conclusions : ESRT was associated with low complication rate , and not worsening the patients ’ quality of life Stereotactic body radiation therapy ( SBRT ) provides a promising way to treat locally advanced pancreatic cancer and borderline resectable pancreatic cancer . A simultaneous integrated boost ( SIB ) to the region of vessel abutment or encasement during SBRT has the potential to downstage otherwise likely positive surgical margins . Despite the potential benefit of using SIB-SBRT , the ability to boost is limited by the local geometry of the organs at risk ( OARs ) , such as stomach , duodenum , and bowel ( SDB ) , relative to tumor . In this study , we have retrospectively replanned 20 patients with 25Gy prescribed to the planning target volume ( PTV ) and 33~80Gy to the boost target volume ( BTV ) using an SIB technique for all patients . The number of plans and patients able to satisfy a set of clinical ly established constraints is analyzed . The ability to boost vessels ( within the gross target volume [ GTV ] ) is shown to correlate with the overlap volume ( OLV ) , defined to be the overlap between the GTV + a 1(OLV1)- or 2(OLV2)-cm margin with the union of SDB . Integral dose , boost dose contrast ( BDC ) , biologically effective BDC , tumor control probability for BTV , and normal tissue complication probabilities are used to analyze the dosimetric results . More than 65 % of the cases can deliver a boost to 40Gy while satisfying all OAR constraints . An OLV2 of 100cm(3 ) is identified as the cutoff volume : for cases with OLV2 larger than 100cm(3 ) , it is very unlikely the case could achieve 25Gy to the PTV while successfully meeting all the OAR constraints AIM Aim of this study was to perform a planning feasibility analysis of a 3-level dose prescription using an IMRT-SIB technique . BACKGROUND Radiation therapy of locally advanced pancreatic cancer should administer a minimum dose to the duodenum and a very high dose to the vascular infiltration areas to improve the possibility of a radical resection . MATERIAL S AND METHODS Fifteen patients with pancreatic head adenocarcinoma and vascular involvement were included . The duodenal PTV ( PTVd ) was defined as the GTV overlapping the duodenal PRV . Vascular CTV ( CTVv ) was defined as the surface of contact or infiltration between the tumor and vessel plus a 5 mm margin . Vascular PTV ( PTVv ) was considered as the CTVv plus an anisotropic margin . The tumor PTV ( PTVt ) was defined as the GTV plus a margin including the PTVv and excluding the PTVd . The following doses were prescribed : 30 Gy ( 6 Gy/fraction ) to PTVd , 37.5 Gy ( 7.5 Gy/fraction ) to PTVt , and 45 Gy ( 9 Gy/fraction ) to PTVv , respectively . Treatment was planned with an IMRT technique . RESULTS The primary end-point ( PTVv Dmean > 90 % ) was achieved in all patients . PTVv D98 % > 90 % was achieved in 6 patients ( 40 % ) . OARs constraints were achieved in all patients . CONCLUSIONS Although the PTVv D95 % > 95 % objective was achieved only in 40 % of patients , the study showed that in 100 % of patients it was possible to administer a strongly differentiated mean/median dose . Prospect i ve trials based on clinical application of this strategy seem to be justified in selected patients without overlap between PTVd and PTVv PURPOSE A Phase I-II dose-escalation study was performed to evaluate the possible impact of the dose on response , toxicity , pain relief , and outcome in patients with unresectable pancreatic carcinoma . METHODS AND MATERIAL S A total of 50 patients entered the study . The external beam radiotherapy ( RT ) dose was 39.6 Gy in the first 15 patients , 50.4 Gy in the next 15 patients , and 59.4 Gy in the remaining 20 patients , at five 1.8-Gy fractions weekly . During external beam RT , patients received concurrent continuous infusion of 5-fluorouracil ( 1000 mg/m(2 ) on Days 1 - 4 and 21 - 24 ) . Patients were evaluated for toxic reactions , local disease control , survival , and pain relief . RESULTS No treatment-related deaths occurred from acute toxicity . Four patients required a temporary treatment interruption because of acute hematologic ( 2 patients ) or GI ( 2 patients ) toxicity , not correlated with the delivered RT dose . Three patients ( 6 % ) developed late toxicity ( duodenal ulcer in 2 and duodenal stenosis in 1 ) . All patients who developed late toxicity had received a dose of 59.4 Gy . At univariate analysis , only the RT dose correlated significantly with the incidence of late toxicity ( at 2 years , 
    Output:
    
SBRT  achieves pain relief in most patients with pancreatic cancer with an acceptable gastrointestinal toxicity rate .