Elevated tumor-to-liver uptake ratio (TLR) from 18F–FDG-PET/CT predicts poor prognosis in stage IIA colorectal cancer following curative resection

Abstract

PurposeThe prognostic value of the tumor-to-liver uptake ratio (TLR) from 18-fluoro-2-deoxyglucose positron emission tomography/computed tomography (18F–FDG-PET/CT) in the early stage of colorectal cancer (CRC) is unclear. Notably, some stage IIA CRC patients experience early recurrence even after curative resection and might benefit from neoadjuvant or adjuvant chemotherapy. This study aims to evaluate whether elevated TLR from 18F–FDG-PET/CT can predict poor prognosis in stage IIA CRC patients undergoing curative resection.MethodsFrom April 2010 to December 2013, 504 consecutive CRC patients with different TNM stages (I-IV) underwent 18F–FDG-PET/CT scans at the 6th Affiliated Hospital of Sun Yat-Sen University. Among the patients, 118 with stage IIA CRC who accepted preoperative 18F–FDG-PET/CT scanning and were treated with curative surgery alone were reviewed retrospectively. The maximum standardized uptake value (SUVmax) in the primary tumor, TLR, and demographic, clinical, histopathological, and laboratory data were analyzed. Receiver operating characteristic (ROC) curve, univariate and multivariate analyses were performed to identify prognostic factors associated with patient disease-free survival (DFS) and overall survival (OS).ResultsROC curve analysis demonstrated that TLR was superior to primary tumor SUVmax in predicting the risk of recurrence in stage IIA CRC. The optimal TLR cutoff was 6.2. Univariate analysis indicated that elevated TLR, tumor size, and lymphovascular/neural invasion correlated with DFS (P = 0.001, P = 0.002, and P = 0.001, respectively) and OS (P = 0.001, P = 0.003, and P < 0.001, respectively). The 1-, 3-, and 5-year DFS rates were 98.4%, 96.9%, and 96.9% for stage IIA CRC patients with lower TLR (≤6.2) versus 77.8%, 60.6%, and 60.6% for those with elevated TLR (>6.2), respectively. The 1-, 3-, and 5-year OS rates were 100.0%, 100.0%, and 98.3% for the patients with lower TLR versus 98.1%, 83.3%, and 74.3% for those with elevated TLR. Cox regression analysis showed that elevated TLR [>6.2; hazard ratio (HR): 3.109–57.463; P < 0.001] and tumor size (>4.4 cm; HR: 1.636–19.155; P = 0.006) were independent risk factors for DFS. Meanwhile, elevated TLR (>6.2; HR: 1.398–84.945; P = 0.023) and lymphovascular/neural invasion (positive; HR: 1.278–12.777; P = 0.017) were independent risk factors for OS.ConclusionElevated TLR predicted worse DFS and OS for stage IIA CRC patients and might serve as a potential radiological index to identify candidates for neoadjuvant or adjuvant chemotherapy. Stage IIA CRC patients with elevated TLR should be monitored carefully for early detection of possible recurrence.

The metabolic clinical risk score as a new prognostic model for surgical decision‐making in patients with colorectal liver metastases

“…We also hypothesized that the combination of these metabolic criteria with the standard CRS risk 17,19,20 It has been shown in various cancers that high FDG uptake is associated with poorer prognosis. 21,23 In colorectal cancer and in CRLM, the prognostic value of 18 FDG-PET/CT has also been demonstrated, but its value in association with a clinical score has not yet been explored. 20,[24][25][26][27][28] We first observed that individual preoperative clinicopathological factors, CRS scores, and high-and low-risk CRS were not significantly different between patients who had the opposite postoperative oncological outcomes, confirming the poor prognostic accuracy of traditional clinical surrogates.…”

“…[18][19][20] The predictive and prognostic value of metabolic parameters derived from preoperative 18 FDG-PET/CT has already been demonstrated in several cancers including lung, esophageal, and colorectal neoplasms. [21][22][23] In CRLM, several studies have also demonstrated the prognostic value of the metabolic parameters measured during preoperative 18 FDG-PET/CT. 20,[24][25][26][27][28] In the present study, we analyzed whether baseline 18 FDG-PET/ CT metabolic characteristics of CRLM may serve to discriminate between patients who will obtain a significant oncological benefit from surgery and those who will not.…”

Quantification: there is more to worry about than good scanner hardware and reliable calibration

“…So far, in oncological PET, especially the tumour to liver ratio (TLR) has been used (one example of this approach is the work of Huang et al [7]). More recently, we have proposed the imagederived tumour to arterial blood standard uptake ratio (SUR) as a promising alternative [8,9] and investigated its properties and performance compared to SUV [5,10,11].…”

“…Nevertheless, we can discriminate tumour viability from the immune reaction that will control the tumour or even destroy it. Actually, the intensity of the immune reaction might be a prognostic marker as suggested by Huang et al and others [7,15].…”

Radiomics Features of 18F-fluorodeoxyglucose Positron-Emission Tomography as a Novel Prognostic Signature in Colorectal Cancer

“…Some studies have demonstrated that conventional PET-derived parameters, such as maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG), carry their own significance in stratifying survival of patients with CRC [5][6][7][8]. However, other studies yielded equivocal results [9,10]. The prognostic impact of those conventional PET-based parameters was not evident for patients with CRC, and the National Comprehensive Cancer Network guidelines recommended that 18 F-FDG-PET or PET/CT should be used selectively for potentially surgically curable metastatic diseases or should only be used to evaluate an equivocal finding on a contrastenhanced CT or MRI [11].…”