BACKGROUND: Early identification of inadequate response to preoperative chemoradiotherapy (CRT) may spare rectal cancer patients the toxicity of ineffective treatment. We prospectively evaluated tumor response with (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) early in the course of preoperative CRT. METHODS: A total of 27 prospectively accrued patients with locally advanced rectal cancer (T(3-4)/N(1)) received preoperative CRT (5040 cGy + 5FU-based chemotherapy). Patients underwent PET scanning before and 8-14 days after commencement of CRT. Scans were interpreted using 3 standard parameters: SUV(max), SUV(avg), and total lesion glycolysis (TLG) as well as an investigational parameter: visual response score (VRS). Percent pathologic response was quantified as a continuous variable. All PET parameters were correlated with pathology. Pathologic complete/near-complete response was defined as ≥95% tumor destruction, suboptimal response as <95%. Statistical analysis was performed using the Wilcoxon rank sum test and receiver operating characteristic (ROC) curve analysis. RESULTS: Of the 27 patients, 11 (41%) had pathologic complete/near-complete response; 16 (59%) had suboptimal response. SUV(max), SUV(avg), and TLG did not discriminate between responders and nonresponders. Visual response score (VRS) was statistically significantly higher for complete/near-complete responders than for suboptimal responders (65 vs. 33%, P = 0.02). Suboptimal responders were identified with 94% sensitivity and 78% accuracy using a VRS cut-off of 50%. CONCLUSIONS: In this pilot study, FDG-PET at 8-14 days after the beginning of preoperative CRT was unsuccessful at predicting pathological response with enough accuracy to justify an early change in therapy.
BACKGROUND: Early identification of inadequate response to preoperative chemoradiotherapy (CRT) may spare rectal cancerpatients the toxicity of ineffective treatment. We prospectively evaluated tumor response with (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET) early in the course of preoperative CRT. METHODS: A total of 27 prospectively accrued patients with locally advanced rectal cancer (T(3-4)/N(1)) received preoperative CRT (5040 cGy + 5FU-based chemotherapy). Patients underwent PET scanning before and 8-14 days after commencement of CRT. Scans were interpreted using 3 standard parameters: SUV(max), SUV(avg), and total lesion glycolysis (TLG) as well as an investigational parameter: visual response score (VRS). Percent pathologic response was quantified as a continuous variable. All PET parameters were correlated with pathology. Pathologic complete/near-complete response was defined as ≥95% tumor destruction, suboptimal response as <95%. Statistical analysis was performed using the Wilcoxon rank sum test and receiver operating characteristic (ROC) curve analysis. RESULTS: Of the 27 patients, 11 (41%) had pathologic complete/near-complete response; 16 (59%) had suboptimal response. SUV(max), SUV(avg), and TLG did not discriminate between responders and nonresponders. Visual response score (VRS) was statistically significantly higher for complete/near-complete responders than for suboptimal responders (65 vs. 33%, P = 0.02). Suboptimal responders were identified with 94% sensitivity and 78% accuracy using a VRS cut-off of 50%. CONCLUSIONS: In this pilot study, FDG-PET at 8-14 days after the beginning of preoperative CRT was unsuccessful at predicting pathological response with enough accuracy to justify an early change in therapy.
Authors: R O Perez; A Habr-Gama; G P São Julião; P B Lynn; C Sabbagh; I Proscurshim; F G Campos; J Gama-Rodrigues; S C Nahas; C A Buchpiguel Journal: Tech Coloproctol Date: 2014-02-08 Impact factor: 3.781
Authors: Oliver S Chow; Deborah Kuk; Metin Keskin; J Joshua Smith; Niedzica Camacho; Raphael Pelossof; Chin-Tung Chen; Zhenbin Chen; Karin Avila; Martin R Weiser; Michael F Berger; Sujata Patil; Emily Bergsland; Julio Garcia-Aguilar Journal: Ann Surg Oncol Date: 2016-03-28 Impact factor: 5.344
Authors: In Ja Park; Y Nancy You; John M Skibber; Miguel A Rodriguez-Bigas; Barry Feig; Sa Nguyen; Chung-Yuan Hu; George J Chang Journal: Dis Colon Rectum Date: 2013-02 Impact factor: 4.585