Erschienen in:
01.09.2013 | Original Article
Predictive value of 18FDG PET-CT for tumour response in patients with locally advanced rectal cancer treated by preoperative chemoradiotherapy
verfasst von:
Jong Wan Kim, Hyun Chul Kim, Ji Won Park, Sung Chan Park, Dae Kyung Sohn, Hyo Seong Choi, Dae Yong Kim, Hee Jin Chang, Ji Yeon Baek, Sun Young Kim, Seok Ki Kim, Jae Hwan Oh
Erschienen in:
International Journal of Colorectal Disease
|
Ausgabe 9/2013
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Abstract
Purpose
Although 18fluorine-2-deoxy-D-glucose positron emission tomography-computed tomography (18FDG PET-CT) is considered a reliable modality for determining tumour response after neoadjuvant chemoradiotherapy (CRT) in locally advanced rectal cancer (LARC), the role of 18FDG PET-CT for predicting pathologic complete response (pCR) remains unclear. The aim of this study was to evaluate whether 18FDG PET-CT can predict tumour response after CRT in patients with LARC, in terms of downstaging and pCR.
Methods
Between March 2009 and February 2012, 151 patients with LARC treated with neoadjuvant CRT followed by radical surgery were reviewed retrospectively. Pre-CRT SUVmax (maximum standardized uptake value), post-CRT SUVmax, ΔSUVmax (difference between pre- and post-CRT SUVmax), and RI-SUV (response index) were measured before and after CRT. Univariate and multivariate analyses were used to analyse the association of PET-CT-related parameters and clinical variables, to assess downstaging and pCR.
Results
Downstaging occurred in 48 patients (31.7 %) and pCR in 19 patients (12.5 %). Univariate and multivariate analysis revealed post-CRT SUVmax as a significant factor for prediction of downstaging, with sensitivity of 60.4 %, specificity of 65.0 %, and accuracy of 55.9 %, for a cutoff value of 3.70. Regarding pCR, post-CRT SUVmax was again found as a significant parameter by univariate and multivariate analysis, with sensitivity of 73.7 %, specificity of 63.7 %, and accuracy of 64.9 %, for a cutoff value of 3.55.
Conclusions
The results indicate that post-CRT SUVmax independently predicts downstaging and pCR. However, the predictive values of post-CRT SUVmax for tumour response after neoadjuvant CRT are too low in sensitivity and specificity to change the treatment plan for LARC.