In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 30, No. 15_suppl ( 2012-05-20), p. e21118-e21118
Abstract:
e21118 Background: A favourable outcome is associated with pCR in LARC treated with NACR; pCR prediction through functional imaging may help the prospective evaluation of management strategies alternative to standard surgery. The aim of this prospective study was to identify whether FDG-PET activity and early/late response predicted independently pCR. Methods: Patients with histologically diagnosed cT3-4 and/or N+ primary rectal cancer were treated homogeneously with NACR (simultaneous boost technique radiotherapy 54 Gy on GTV/24 fractions plus capecitabine 1650 mg/mq/day) and total mesorectal excision 7-8 weeks later. FDG-PET uptake, expressed as maximum standardized uptake value, was obtained at baseline (SUV-1), at interim (2 weeks after treatment start: SUV-2) and 6 weeks after NARC completion (SUV-3) and was calculated as percentage difference (Δ-SUV). The role of SUV-1, SUV-2, SUV-3, Δ-SUV(1-2) and Δ-SUV(1-3) for pCR prediction was assessed using logistic regression analysis; ROC analysis was performed to identify the optimal thresholds. Results: The study enrolled 30 pts (median age 59 yrs; 12M:18F) treated from January 2009 to November 2011 at Istituto Nazionale Tumori of Milan. All underwent FDG-PET at baseline and post-NACR and 80% consented to an interim assessment; one patient was excluded due to surgery refusal. pCR rate was 28%. Among all parameters, only post-NACR SUV (mean 4 +/- 1.7 for pCR vs 8.7 +/-5.8 for non-pCR; P=0.001 by Mann-Whitney test) showed significant association with pCR at univariate analysis (P=0.03). At multivariate analysis including baseline SUV, post-NACR SUV, Δ-SUV, age (≤ or 〉 65 yrs), sex (F or M) and pre-treatment stage (N- or N+/cT3 or cT4), only female sex and post-NACR SUV predicted independently pCR (both P=0.01). With ROC analysis, a post-NACR SUV threshold 〈 5.5 had 88% sensitivity and 81% specificity, with 83% overall accuracy. Conclusions: The SUV cut-off of 5.5, explained by inflammatory modifications, could limit the applicability in clinical practice assuming values ≤2.5 for negativity. However, FDG-PET SUV post-NACR may serve as useful predictive biomarker in LARC.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/jco.2012.30.15_suppl.e21118
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2012
detail.hit.zdb_id:
2005181-5
Permalink