Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2011 Oct;18(10):2783-9.
doi: 10.1245/s10434-011-1634-2. Epub 2011 Apr 8.

Evaluation of ¹⁸F-FDG-PET for early detection of suboptimal response of rectal cancer to preoperative chemoradiotherapy: a prospective analysis

Tobias Leibold  1 , Timothy J Akhurst, David B Chessin, Henry W Yeung, Homer Macapinlac, Jinru Shia, Bruce D Minsky, Leonard B Saltz, Elyn Riedel, Madhu Mazumdar, Philip B Paty, Martin R Weiser, W Douglas Wong, Steven M Larson, José G Guillem
Affiliations

Evaluation of ¹⁸F-FDG-PET for early detection of suboptimal response of rectal cancer to preoperative chemoradiotherapy: a prospective analysis

Tobias Leibold et al. Ann Surg Oncol. 2011 Oct.

Abstract

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.

PubMed Disclaimer

Figures

Figure 1:
Figure 1:. Example of 18F-FDG PET scan prior to (baseline) and 10 days after (intermediate) commencement of preoperative CRT
The image to the left shows a baseline 18F-FDG-PET in a patient with rectal cancer (arrow indicates the rectal cancer). The image to the right shows an intermediate 18F-FDG-PET in the same patient performed 10 days after commencement of CRT. (18F-FDG-PET, 18F-fluorodeoxyglucose positron emission tomography; CRT, chemoradiotherapy)
Figure 2:
Figure 2:. ROC analysis for VRS
Using a VRS cut-off of 50%, sensitivity = 94% and specificity = 55%. (VRS, visual response score; ROC, receiver operating characteristic)
Figure 3:
Figure 3:. Concordance Correlation Coefficient:
0.72 (indicates fair agreement) Concordance between two PET readers regarding VRS
See this image and copyright information in PMC

References

    1. Sauer R, Becker H, Hohenberger W, Rodel C, et al. German Rectal Cancer Study Group: Preoperative versus postoperative chemoradiotherapy for rectal cancer. N Engl J Med 2004;351:1731–1740. - PubMed
    1. Grann A, Feng C, Wong D, et al. Preoperative combined modality therapy for clinically resectable uT3 rectal adenocarcinoma. Int J Radiat Oncol Biol Phys 2001;49:987–995. - PubMed
    1. Garcia-Aguilar J, Hernandez de Anda E, Sirivongs P, et al. A pathologic complete response to preoperative chemoradiation is associated with lower local recurrence and improved survival in rectal cancer patients treated by mesorectal excision. Dis Colon Rectum 2003;46:298–304. - PubMed
    1. Medich D, McGinty J, Parda D, et al. Preoperative chemoradiotherapy and radical surgery for locally advanced distal rectal adenocarcinoma: pathologic findings and clinical implications. Dis Colon Rectum 2001;44:1123–1128. - PubMed
    1. Onaitis MW, Noone RB, Fields R, et al. Complete response to neoadjuvant chemoradiation for rectal cancer does not influence survival. Ann Surg Oncol 2001;8:801–806. - PubMed

Publication types

MeSH terms

LinkOut - more resources