TY - JOUR
T1 - Optimal timing for assessment of tumor response to neoadjuvant chemoradiation in patients with rectal cancer
T2 - Do all patients benefit from waiting longer than 6 weeks?
AU - Perez, Rodrigo O.
AU - Habr-Gama, Angelita
AU - São Julião, Guilherme P.
AU - Gama-Rodrigues, Joaquim
AU - Sousa, Afonso H.S.
AU - Campos, Fabio Guilherme
AU - Imperiale, Antonio R.
AU - Lynn, Patricio B.
AU - Proscurshim, Igor
AU - Nahas, Sergio Carlos
AU - Ono, Carla Rachel
AU - Buchpiguel, Carlos Alberto
N1 - Funding Information:
This work was supported by the Brazilian research funding agencies CNPq , grant no. 483752/2006-1 , and FAPESP , grant no. 07/51069-01 .
PY - 2012/12/1
Y1 - 2012/12/1
N2 - Purpose: To estimate the metabolic activity of rectal cancers at 6 and 12 weeks after completion of chemoradiation therapy (CRT) by 2-[fluorine-18] fluoro-2-deoxy-d-glucose-labeled positron emission tomography/computed tomography ([18FDG]PET/CT) imaging and correlate with response to CRT. Methods and Materials: Patients with cT2-4N0-2M0 distal rectal adenocarcinoma treated with long-course neoadjuvant CRT (54 Gy, 5-fluouracil-based) were prospectively studied (ClinicalTrials.org identifier NCT00254683). All patients underwent 3 PET/CT studies (at baseline and 6 and 12 weeks from CRT completion). Clinical assessment was at 12 weeks. Maximal standard uptake value (SUVmax) of the primary tumor was measured and recorded at each PET/CT study after 1 h (early) and 3 h (late) from 18FDG injection. Patients with an increase in early SUVmax between 6 and 12 weeks were considered "bad" responders and the others as "good" responders. Results: Ninety-one patients were included; 46 patients (51%) were "bad" responders, whereas 45 (49%) patients were "good" responders. "Bad" responders were less likely to develop complete clinical response (6.5% vs. 37.8%, respectively; P=.001), less likely to develop significant histological tumor regression (complete or near-complete pathological response; 16% vs. 45%, respectively; P=.008) and exhibited greater final tumor dimension (4.3 cm vs. 3.3 cm; P=.03). Decrease between early (1 h) and late (3 h) SUVmax at 6-week PET/CT was a significant predictor of "good" response (accuracy of 67%). Conclusions: Patients who developed an increase in SUVmax after 6 weeks were less likely to develop significant tumor downstaging. Early-late SUVmax variation at 6-week PET/CT may help identify these patients and allow tailored selection of CRT-surgery intervals for individual patients.
AB - Purpose: To estimate the metabolic activity of rectal cancers at 6 and 12 weeks after completion of chemoradiation therapy (CRT) by 2-[fluorine-18] fluoro-2-deoxy-d-glucose-labeled positron emission tomography/computed tomography ([18FDG]PET/CT) imaging and correlate with response to CRT. Methods and Materials: Patients with cT2-4N0-2M0 distal rectal adenocarcinoma treated with long-course neoadjuvant CRT (54 Gy, 5-fluouracil-based) were prospectively studied (ClinicalTrials.org identifier NCT00254683). All patients underwent 3 PET/CT studies (at baseline and 6 and 12 weeks from CRT completion). Clinical assessment was at 12 weeks. Maximal standard uptake value (SUVmax) of the primary tumor was measured and recorded at each PET/CT study after 1 h (early) and 3 h (late) from 18FDG injection. Patients with an increase in early SUVmax between 6 and 12 weeks were considered "bad" responders and the others as "good" responders. Results: Ninety-one patients were included; 46 patients (51%) were "bad" responders, whereas 45 (49%) patients were "good" responders. "Bad" responders were less likely to develop complete clinical response (6.5% vs. 37.8%, respectively; P=.001), less likely to develop significant histological tumor regression (complete or near-complete pathological response; 16% vs. 45%, respectively; P=.008) and exhibited greater final tumor dimension (4.3 cm vs. 3.3 cm; P=.03). Decrease between early (1 h) and late (3 h) SUVmax at 6-week PET/CT was a significant predictor of "good" response (accuracy of 67%). Conclusions: Patients who developed an increase in SUVmax after 6 weeks were less likely to develop significant tumor downstaging. Early-late SUVmax variation at 6-week PET/CT may help identify these patients and allow tailored selection of CRT-surgery intervals for individual patients.
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U2 - 10.1016/j.ijrobp.2012.01.096
DO - 10.1016/j.ijrobp.2012.01.096
M3 - Article
C2 - 22580120
AN - SCOPUS:84869141639
SN - 0360-3016
VL - 84
SP - 1159
EP - 1165
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 5
ER -