***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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    ***EXAMPLES*** 
    Input: PURPOSE To evaluate the impact of preoperative chemoradiation with raltitrexed ( Tomudex(1 ) ) on tumor response , sphincter preservation , and toxicity in patients with locally advanced rectal cancer . METHODS AND MATERIAL S Between 1998 and 2002 , 54 consecutive patients with Stage T3 or T2N+ resectable rectal carcinoma were treated with preoperative chemoradiation , i.v . bolus of raltitrexed on Days 1 , 19 , and 38 and concurrent 50 Gy external beam radiotherapy . Surgery was performed 6 - 8 weeks after the end of chemoradiation . RESULTS No patients had Grade 4 acute toxicity . Grade 3 acute toxicity occurred in 16.6 % of cases and was hematologic in 6 patients and GI in 2 . The overall clinical response rate was 88.8 % , with a complete response in 5.5 % , partial response in 83.3 % , and no change in 9.2 % . No patient showed disease progression . All patients underwent surgery . Sphincter saving was obtained in 83.3 % of patients . No perioperative mortality occurred , and the perioperative morbidity rate was 5.5 % . Of 20 resected patients ( 37 % ) who were c and i date s for abdominoperineal resection at diagnosis ( anorectal ring distance < or = 30 mm ) , 13 ( 65 % ) underwent a sphincter-saving procedure . At pathologic examination , 13 ( 24 % ) of 54 patients had a complete pathologic response ( pT0 ) and 10 ( 18.5 % ) had rare isolated residual cancer cells ( pT , microscopic foci ) . Overall , 42.5 % had major downstaging . The tumor regression grade ( TRG ) , using M and ard 's score system , was also applied and was TRG1 in 13 patients , TRG2 in 11 , TRG3 in 20 , and TRG4 in 10 patients ; no patient had TRG5 . CONCLUSION The use of raltitrexed in a neoadjuvant chemoradiation schedule promoted high pathologic tumor downstaging and use of a sphincter-saving procedure . The low toxicity profile supports the rationale to explore raltitrexed combined with other drugs with different biologic targets Background Magnetic resonance imaging ( MRI ) methods for chemoradiotherapy ( CRT ) response assessment of rectal cancer include posttreatment T staging ( ymrT ) , tumor regression grading ( mrTRG ) , volume reduction posttreatment , and modified RECIST measurement . We compared these methods in identifying good versus poor responders with the histopathological st and ards of T stage ( ypT ) and tumor regression grading ( TRG ) . Methods A total of 86 patients underwent CRT in a prospect i ve phase II trial for MRI-defined locally advanced rectal cancer . Two readers independently assessed MRIs for ymrT , mrTRG , volume change , and RECIST . Parameters for each case were categorized as good or poor response and analyzed against ypT and TRG by univariate logistic regression . Results A total of 83 patients had evaluable imaging , and 78 had final pathology ( five did not undergo surgery ) . Of these , 34 patients had good response ( ypT0 - 3a ) and 44 had poor response ( > ypT3a ) . Also , 27 patients had favorable pathologic TRG ( predominant fibrosis ) and 51 had unfavorable TRG ( predominant tumor ) . Good mrTRG and ymr < T3b stage were both significantly ( P = 0.001 ) associated with favorable pathology odds ratio [ OR ] = 16.11 ( 95 % confidence interval [ 95 % CI ] : 3.36–77.29 ) and 17.50 ( 95 % CI : 5.38–56.89 ) , respectively . RECIST measurements and volume reduction of > 80 % showed an OR of 3.23 ( 95 % CI : 1.14–9.17 ) , 4.25 ( 95 % CI : 0.92–15.45 ) , respectively , for a good ypT score ( P = 0.028 ) , but there was no association for histopathological TRG . Conclusion Favorable and unfavorable histopathology are predicted by both ymrT and mrTRG , and we recommend these parameters for post-treatment assessment of rectal cancers treated with CRT PURPOSE We assessed the impact of  tumor regression grading  ( TRG ) and its value in correlation to established prognostic factors in a cohort of rectal carcinoma patients treated by preoperative chemoradiotherapy ( CRT ) .  PATIENTS AND METHODS TRG was evaluated on surgical specimens of 385 patients treated within the preoperative CRT arm of the CAO/ARO/AIO-94 trial :  50.4 Gy was delivered , fluorouracil was given in the first and fifth week , and surgery was performed 6 weeks thereafter . TRG was determined by the amount of viable tumor versus fibrosis , ranging from TRG 4 when no viable tumor cells were detected , to TRG 0 when fibrosis was completely absent . TRG 3 was defined as regression more than 50 % with fibrosis outgrowing the tumor mass , TRG 2 was defined as regression less than 50 % , and TRG 1 was defined basically as a morphologically unaltered tumor mass . We performed an initially unplanned , hypothesis-generating analysis with respect to the prognostic value of this TRG system . RESULTS TRG 4 , 3 , 2 , 1 , 0 was found in 10.4 % , 52.2 % , 13.8 % , 15.3 % , and 8.3 % of the resected specimens , respectively . Five-year disease-free survival ( DFS ) after CRT and curative resection was 86 % for TRG 4 , 75 % for grouped TRG 2 + 3 , and 63 % for grouped TRG 0 + 1 ( P = .006 ) . On multivariate analysis , the pathologic T category and the nodal status after CRT were the most important independent prognostic factors for DFS . CONCLUSION In this exploratory analysis , complete ( TRG 4 ) and intermediate pathologic response ( TRG 2 + 3 ) suggested improved DFS after preoperative CRT . TRG assessment should be implemented in pathologic evaluation and prospect ively vali date d in further studies PURPOSE The aim this study was to determine the pathologic complete response ( pCR ) rate defined as tumor regression grade 1 ( TRG1 ) and toxicity profile of the combination of high-dose pre-operative radiotherapy and simultaneous UFT/leucovorin ( LV ) in patients with locally advanced rectal cancer . MATERIAL S/ METHODS Eligibility included biopsy proven rectal adenocarcinoma ; T3-T4 N0-N2 ; performance status < 2 ( ECOG ) and adequate blood , hepatic and renal function . Treatment consisted of radiotherapy 54 Gy at 1.8 Gy/day and UFT 300 mg/m(2)/day and LV 60 mg/day , given simultaneously daily for 6 weeks . Surgery was performed within 4 - 6 weeks period after chemoradiotherapy . Patients who did not achieve TGR1 were to receive 4 cycles of adjuvant UFT/LV on days 1 - 28 , every 5 weeks . RESULTS Sixty-eight patients were included . All but one received full dose of radiation and 62 had the total planned pre-operative UFT/LV dose . Grade 3 toxicities were diarrhea 7 % and proctitis 3 % . Complete resection was achieved in 62 patients ( 91 % ) . Tumor regression grade 1 ( TRG1 ) was seen in 11 patients ( 16 % ) . Forty-eight patients received adjuvant UFT/LV . Grade 3 toxicity during adjuvant UFT/LV included diarrhea 12 % , asthenia 4 % , neutropenia 2 % , and h and -foot syndrome 2 % . The 3-year disease-free survival was 71 % . CONCLUSIONS Simultaneous high-dose pre-operative localized radiation therapy concurrent with UFT/LV is feasible and has a low toxicity profile . This schedule is highly effective and merits further investigation BACKGROUND AND PURPOSE To explore the utility of tumour regression grading ( TRG , the amount of residual tumour cells in relation to extension of fibrosis ) after  chemoradiation  of rectal cancer . MATERIAL S AND METHODS Of 131 patients who received preoperative chemoradiation in the frame of the r and omized trial , pathological complete response ( pCR , TRG0 ) , good regression ( TRG1 ) , moderate regression ( TRG2 ) , and poor regression ( TRG3 ) were recorded in 17 % , 31 % , 31 % , and 22 % of patients , respectively . RESULTS The rates of ypN-positive category for TRG0 , TRG1 , TRG2 , and TRG3 groups were 5 % , 23 % , 45 % , and 46 % , respectively , p=0.001 . When ypT-category and TRG were evaluated by the logistic regression analysis , only ypT-category remained significant for independent prediction of the risk for mesorectal nodal metastases , p=0.006 . The 4-year ( median follow-up ) disease-free survival ( DFS ) for TRG0 , TRG1 , TRG2 , and TRG3 groups were 91 % , 67 % , 54 % , and 47 % . When patients with persistent disease ( TRG1 vs. TRG2 vs. TRG3 ) were analyzed separately , TRG had no prognostic value for DFS , p=0.402 . CONCLUSIONS TRG in patients with residual cancer had no prognostic value for the incidence of nodal disease and for DFS . Our findings and literature data question the need for the inclusion of TRG assessment into a routine pathological report AIM The value of grading tumor regression after neoadjuvant therapy  of rectal carcinoma was evaluated . PATIENTS AND METHODS Analysis was carried out using prospect i ve data of 225 patients with rectal carcinoma treated by neoadjuvant radiochemotherapy followed by radical resection with curative intent .  For the histological regression grading , the method of Dworak et al. ( 1997 ) was used with a slight modification . RESULTS After neoadjuvant radiochemotherapy , the most important prognostic factors are pathologically assessed circumferential resection margin , quality of surgery ( plane of surgery ) , and the ypT and ypN classification . In addition , the histological regression grade of primary tumor and regional lymph nodes influence outcome , especially the local recurrence rate . CONCLUSION After neoadjuvant therapy , the histological tumor regression grading should be assessed . A regression grading system based on the proposals of Dworak et al. ( 1997 ) is recommended PURPOSE To assess magnetic resonance imaging ( MRI ) and pathologic staging after neoadjuvant therapy for rectal cancer in a prospect ively enrolled , multicenter study . METHODS In a prospect i ve cohort study , 111 patients who had rectal cancer treated by neoadjuvant therapy  were assessed for response by MRI and pathology staging by T , N and circumferential resection margin ( CRM ) status . Tumor regression grade ( TRG ) was also assessed by MRI .  Overall survival ( OS ) was estimated by using the Kaplan-Meier product-limit method , and Cox proportional hazards models were used to determine associations between staging of good and poor responders on MRI or pathology and survival outcomes after controlling for patient characteristics . RESULTS On multivariate analysis , the MRI-assessed TRG ( mrTRG ) hazard ratios ( HRs ) were independently significant for survival ( HR , 4.40 ; 95 % CI , 1.65 to 11.7 ) and disease-free survival ( DFS ; HR , 3.28 ; 95 % CI , 1.22 to 8.80 ) . Five-year survival for poor mrTRG was 27 % versus 72 % ( P = .001 ) , and DFS for poor mrTRG was 31 % versus 64 % ( P = .007 ) . Preoperative MRI-predicted CRM independently predicted local recurrence ( LR ; HR , 4.25 ; 95 % CI , 1.45 to 12.51 ) . Five-year survival for poor post-treatment pathologic T stage ( ypT ) was 39 % versus 76 % ( P = .001 ) ; DFS for the same was 38 % versus 84 % ( P = .001 ) ; and LR for the same was 27 % versus 6 % ( P = .018 ) . The 5-year survival for involved pCRM was 30 % versus 59 % ( P = .001 ) ; DFS , 28 versus 62 % ( P = .02 ) ; and LR , 56 % versus 10 % ( P = .001 ) . Pathology node status did not predict outcomes . CONCLUSION MRI assessment of TRG and CRM are imaging markers that predict survival outcomes for good and poor responders and provide an opportunity for the multidisciplinary team to offer additional treatment options before planning definitive surgery . Postoperative histopathology 
    Output:
    
MRI indicates good and poor response by mrTRG1 - 3 and mrTRG4 - 5 , respectively