Correlation Between TRG With SUV Of FDG-PET/CT In Rectal Cancer Treated With Preoperative Concurrent Chemoradiotherapy

Grounding and ObjectiveNeoadjuvant chemoradiotherapy has become the standard treatment of locallyadvanced rectal cancer. However，the response of individual tumors to preoperativechemoradiotherapy has large individual differences, quite a number of patients can’tbenefit from preoperative chemoradiotherapy. Therefore, it is necessary to predictearly colorectal cancer preoperative radiation and chemotherapy curative effect of18f-FDG PET/CT in high-tech functional anatomical imaging techniques, in cancerstaging, remote metastasis and recurrence monitoring application prospect iswidespread, yet in the LARC preoperative chemoradiotherapy for early evaluation ofcurative effect and prediction in terms of value remains controversial. This topic onthe basis of locally advanced rectal cancer to neoadjuvant therapy, use the analysisof locally advanced rectal cancer before and after neoadjuvant therapy for18f-FDGPET/CT SUV differences in metabolic parameters and its change law, to find18f-FDG PET/CT features of metabolic parameters can effective predictors of rectal cancer preoperative chemoradiation therapy, in order to evaluate the efficacy of NAT,early screening in patients with preoperative chemoradiotherapy sensitivity ofdifferent, respectively formulate and adopt suitable or adjusted for treatment, so as torealize the individualized treatment of tumor.Materials and methodsWe carried out a prospective longitudinal study in23patients diag-nosed with locallyadvanced rectal adenocarcinoma (stages II/III) in Shan dong Tumor Hospital betweenJuly2010and December2012, and who were candidates for neoadjuvant concurrentchemoradiotherapy. the total pelvic radiotherapy45-50.4Gy/25-28Fx/35-38days. TheXELOX program concurrent chemotherapy: oxaliplatin80mg/m combined withcapecitabine (1000mg/m BID D1-14), repeated every21days. All the patientsunderwent rectal surgery with curative intent6–8weeks after the end of neoadjuvanttreatment. PET-CT was performed initially for clinical staging at about1week priorto neoadjuvant CRT (pre-CRT PET-CT) and then repeaed5–7week s aftercompletion of chemoradiotherapy. Pre-CRTSUVmax (maximum standardized uptakevalue), post-CRTSUVmax, ΔSUVmax (difference between pre-andpost-CRTSUVmax), and RI-SUV (response index) were measured be-fore and afterCRT. A visual and semiquantitative analysis was carried out. The pathologicalresponse was classified according to the Dworak tumour regression grade (TRG).Then divided the patients with rectal cancer into two groups responders andnon-responders.The different metabolic parameters were analysed and correlated withthe tumour regression grade(TRG) score.Results123cases of patients, the preoperative chemotherapy drop of the16patients(69.6%), pathologic complete remission in5/23(21.7%).2The post-CRT SUVmax was significantly lower than pre-CRT SUVmax(17.2±3.7vs6.0±3.0, p <0.001),The significant differences were observed betweenSUVmax and pre-CRT SUVmax. 3Preoperative chemoradiotherapy responders group and non-responders groupSUV1statistically significant difference (p=0.854) after neoadjuvant chemotherapythe SUV2between the two groups was significant difference (p=0.001) between thetwo groups preoperative chemotherapy changes in the front and rear SUV to valueΔSUV (p=0.016) and the response index RI (p=0.000) between the two groupswere statistically significant. Two groups within the neoadjuvant therapy afterneoadjuvant therapy before SUVmax was significantly lower (17.1±3.2â†'3.8±1.9,p=0.000, vs17.4±4.2â†'8.0±2.4, p=0.000). Statistically significant. Wasobserved.4Put preoperative chemotherapy PCR group and the group of Non-pCR groupof neoadjuvant treatment before SUV1not find statistically significant difference(15.8±2.7vs17.6±3.9, p=0.371), preoperative radiotherapy and chemotherapySUV difference before and after the ΔSUV two groups between not statisticallysignificant (13.5±2.6vs10.5±4.0, p=0.179). Preoperative radiotherapy andchemotherapy from SUV2and two sets of reaction index RI were statisticallysignificant differences (2.2±0.3vs7.0±2.5, p=0.001,84.9±2.4vs61.2±14.2, p=0.001).5RI=63%for predicting preoperative radiotherapy and chemotherapy pCRcan become the best diagnostic cut off value, the sensitivity was80%and a specificityof82.7%. The area under the curve (Area Under The Curve, AUC) of0.841(p=0.037).Conclusions1Preoperative chemoradiotherapy in rectal cancer has been deemed tu reducerumor volume, downstage the tumor, convert an unresectable tumor into a resectabletumor, andu preserve the anal sphincter.218F FDG-PET/CT can be used as a cancer neoadjuvant therapy tools to predictmetabolic activity parameter can predict the short-term efficacy of preoperativeradiotherapy and chemotherapy.3The post-CRT SUV max and RI can predict tumor regression grading.The derived RI cut-off values of63%could be the best predictive factor to Preoperativechemoradiotherapy in rectal cancer..