Clinical usefulness of dual-time FDG PET-CT in assessment of esophageal squamous cell carcinoma

Impact of retention index on the neoadjuvant chemotherapy effect and the prognosis in oesophageal cancer

OBJECTIVE

The relationship between retention index calculated from dual-time point 18F-fluorodeoxyglucose positron emission tomography-computed tomography and oesophageal cancer prognosis remains unknown. This study aimed to determine usefulness of retention index as a predictor of long-term prognosis of oesophageal cancer and neoadjuvant chemotherapy efficacy.

METHODS

A total of 151 patients with oesophageal cancer who underwent esophagectomy were evaluated retrospectively in this study. We acquired positron emission tomography scans 60 and 120 min (SUVmax1 and SUVmax2, respectively) after the intravenous administration of 3.7 Mbq/kg 18F-fluorodeoxyglucose. The patients were divided into two groups: high-retention index (retention index ≥29%, 107 patients) and low-retention index (retention index <29%, 44 patients). Retention index was calculated as follows: retention index (%) = [(SUVmax2 - SUVmax1)/SUVmax1] × 100.

RESULTS

The overall survival and relapse-free survival rates in the high-retention index group were significantly lower than those in the low-retention index group (P < 0.001). Our multivariate analysis identified that the high-retention index group contained independent risk factors for overall survival (hazard ratio: 2.44, P = 0.009) and relapse-free survival (hazard ratio: 2.61, P = 0.002). The high-retention index group exhibited a lower partial response rate to neoadjuvant chemotherapy evaluated by computed tomography (P < 0.001) and a lower pathological therapeutic effect in the resected specimen (P = 0.019) than the low-retention index group.

CONCLUSIONS

The retention index was associated with neoadjuvant chemotherapy responses and long-term prognosis for oesophageal cancer.

Value of 18F-FDG PET/CT in the diagnosis of portal vein tumor thrombus in patients with hepatocellular carcinoma

OBJECTIVE

The aim of this study was to evaluate the usefulness of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) for the diagnosis of a portal vein tumor thrombus (PVTT) in patients with hepatocellular carcinoma (HCC).

METHODS

One hundred fifty-four patients with histologically proven HCC underwent ¹⁸F-FDG PET/CT imaging. The maximum standardized uptake value (SUVmax) was calculated, and the change in SUVmax (retention index, RI) was defined as the ratio of the increase in SUVmax between early and delayed scans to the SUVmax in the early scan. The circular region of interest was placed on the transaxial images according to the corresponding CT images. The final diagnoses of a PVTT were confirmed by histopathology.

RESULTS

Of the patients examined, 101 (65.6%) had no confirmed instances of a PVTT, whereas 53 (34.4%) had a confirmed PVTT. The sensitivity of ¹⁸F-FDG PET/CT imaging was 62.3%, the specificity was 97.0%, the accuracy was 85.1%, the positive predictive value was 91.7%, and the negative predictive value was 83.1%. The SUVmax of the PVTT was 4.32 ± 1.96 and the SUVmax of the HCC lesions for these patients was 5.38 ± 2.79, but these differences were insignificant (t = 1.78, p = 0.08). For dual-time-point imaging, the SUV1 of the PVTT lesions was 3.75 ± 1.48, and SUV2 was 3.63 ± 1.41, but these differences were insignificant (t = 0.82, p = 0.42). The SUV1 of the HCC lesions was 4.47 ± 2.03, and the SUV2 was 4.90 ± 2.07, which were both also insignificant (t = - 1.81, p = 0.09). The RI of the PVTT lesions was - 2.05 ± 19.96%, and the RI of the HCC lesions was 11.87 ± 26.20%, with no significant differences between them (t = 1.58, p = 0.13).

CONCLUSIONS

¹⁸F-FDG PET/CT may potentially improve the accurate diagnoses of a PVTT in patients with HCC.

Systematic review and meta-analysis of the accuracy of 18F-FDG PET/CT for detection of regional lymph node metastasis in esophageal squamous cell carcinoma

Background

We performed a systematic review and meta-analysis to assess the accuracy of 18F-fluorodeoxyglucose positron emission tomography with computer tomography (18F-FDG PET/CT) for detection of regional lymph node metastasis in esophageal squamous cell carcinoma in per-patient and per-nodal station basis.

Methods

Electronic databases were researched for studies assessing the sensitivity and specificity of PET/CT to detect the regional lymph node metastasis published between January 2006 and December 2017 on esophageal squamous cell carcinoma. STATA software was performed to assess the sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odd ratio (DOR) and summary receiver operating characteristic (SROC) curve. The Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) and Deeks' Funnel Plot Asymmetry Test were performed to evaluate the study quality and publication bias of included studies.

Results

Nineteen studies were eligible for meta-analysis, comprising 1,089 patients with esophageal cancer who underwent 18F-FDG PET/CT before surgery. According to the content of the article, we divided the selected studies into per-patient basis group and per-nodal basis group (one of the articles was involved in both groups). For the per-nodal station basis group (12 studies, 5,681 stations), the pooled sensitivity and specificity estimates of 18F-FDG PET/CT for detecting regional lymph node metastasis were 66% [95% confidence interval (CI): 51-78%] and 96% (95% CI: 92-98%), respectively. The corresponding values on a per-patient basis group (8 studies; 506 patients) were 65% (95% CI: 49-78%) and 81% (95% CI: 69-89%) in sensitivity and specificity, respectively.

Conclusions

Overall, 18F-FDG PET/CT have a moderate to low sensitivity and a high to moderate specificity for detection of regional nodal metastasis in esophageal cancer. Therefore, since the false rate is considerable, extending the extent of lymph node dissection or radiotherapy target volume is necessary after diagnosis of regional nodal metastasis by 18F-FDG PET/CT.

Dual time point fluorodeoxyglucose positron emission tomography/computed tomography in differentiation between malignant and benign lesions in cancer patients. Does it always work?

OBJECTIVES

Assess the added value of dual time point F-18-fluorodeoxyglucose positron emission tomography/computed tomography (DTP F-18-FDG-PET/CT) in the differentiation of malignant from a benign lesion in cancer patients.

MATERIALS AND METHODS

Totally, 140 F-18-FDG PET/CT scans of 60 cancer patients who underwent DTP protocol (early whole body PET/CT [E] at 60 min [range, 45-76 min] and delayed limited PET/CT [D] on areas of interest at 120 min [range, 108-153 min] after the tracer injection) were retrospectively reviewed. Visual and semi-quantitative analysis was performed on both early and delayed images. All findings were confirmed by histopathology and/or at least 3 months follow-up (F-18-FDG PET/CT, CT, or magnetic resonance imaging). The result was considered true positive (TP) if delayed standardized uptake value (SUV) of suspicious lesions increased and confirmed to be malignant, false positive (FP) if delayed SUV increased and confirmed to be benign, true negative (TN) if delayed SUV unchanged or decreased and confirmed to be benign, and false negative (FN) if delayed SUV unchanged or decreased and confirmed to be malignant.

RESULTS

A total of 164 suspicious lesions were detected (20 presacral lesions, 18 lung nodules, 18 Hodgkin's disease (HD) lesions, 16 rectal lesions, 16 head and neck (H and N) lesions, 14 hepatic lesions, 14 non-Hodgkin's lymphoma (NHL) lesions, 12 mediastinal lymph nodes (LNs), 10 focal gastric uptake, 10 soft tissue lesions, 8 breast lesions, 4 peritoneal nodule, and 4 others). Sixty-four lesions were pathologically confirmed, and 100 lesions were confirmed based on 3-6 months follow-up. There were 62 TP lesions, 44 FP, 58 TN and no FN results. The overall sensitivity was 100% of DTP F-18-FDG PET/CT in detecting suspicious lesions. The specificity was 57% in differentiating malignant from benign lesions, and the accuracy was 73%. Positive predictive value was 59%, negative predictive value (NPV) 100%. All hepatic lesions were TP. Accuracy in metastatic hepatic lesions HD, presacral soft tissue, lung nodules, H, and N cancer, breast cancer, NHL and mediastinal LN was100%, 88.8%, 80%, 78%, 75%, 75%, 71%, and 33.3%, respectively.

CONCLUSIONS

DTP F-18-FDG-PET/CT protocol does not always work in differentiation between benign and malignant lesions. However; it has high NPV, and promising results was noted in hepatic lesions, lymphoma, and recurrent rectal cancer.

Dual-time-point Imaging and Delayed-time-point Fluorodeoxyglucose-PET/Computed Tomography Imaging in Various Clinical Settings

The techniques of dual-time-point imaging (DTPI) and delayed-time-point imaging, which are mostly being used for distinction between inflammatory and malignant diseases, has increased the specificity of fluorodeoxyglucose (FDG)-PET for diagnosis and prognosis of certain diseases. A gradually increasing trend of FDG uptake over time has been shown in malignant cells, and a decreasing or constant trend has been shown in inflammatory/infectious processes. Tumor heterogeneity can be assessed by using early and delayed imaging because differences between primary versus metastatic sites become more detectable compared with single time points. This article discusses the applications of DTPI and delayed-time-point imaging.

Predictive value of 18F-fluorodeoxyglucose positron emission tomography - computed tomography compared to postoperative pathological findings for patients with non-small-cell lung cancer

This study was conducted to investigate the predictive value of ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG PET-CT) in patients with non-small-cell lung cancer (NSCLC), compared to that of postoperative pathological findings, for T and N staging and the associations of the metabolic parameters of the primary tumor with histological type and differentiation. The preoperative contrast-enhanced CT and ¹⁸F-FDG PET-CT and postoperative pathological findings of 112 NSCLC patients treated with lobectomy or pneumonectomy combined with systematic mediastinal lymphadenectomy were retrospectively reviewed. Compared to the postoperative pathological findings, the effect of contrast-enhanced CT and ¹⁸F-FDG PET-CT on T and N staging were evaluated. The metabolic tumor volume (MTV) and maximum standardized uptake value (SUVmax) of the primary tumor were measured. The associations between these metabolic parameters and histological type and differentiation were also evaluated. The differences in the accuracy in overall staging and T staging between PET-CT and contrast-enhanced CT were significant (91.1 vs. 69.6%, P=0.000; and 92.9 vs. 76.8%, P=0.000, respectively). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of regional lymph node metastasis detection were 91.7, 93.0, 86.5, 95.8 and 92.6%, respectively, with PET-CT; and 71.3, 77.2, 60.6, 84.5 and 75.2%, respectively, with contrast-enhanced CT. The SUVmax (7.29±1.83 vs. 5.91±1.65, t=4.15, P=0.000) and MTV (48.20±22.47 vs. 30.21±19.72 cm³, t=4.48, P=0.000) were significantly higher for squamous cell carcinoma (SCC) compared to those for adenocarcinoma (AC). There was a positive correlation between the MTV and SUVmax of the primary tumor (Pearson's r=0.838, P=0.000). Significant differences were observed among differentiation subgroups in the SUVmax and MTV of the primary tumor for both SCC and AC. In conclusion, compared to the postoperative pathological findings, the predictive value of ¹⁸F-FDG PET-CT for T and N staging in NSCLC was higher compared to that of contrast-enhanced CT. The FDG uptake of the primary tumor was associated with histological type and differentiation and the difference was statistically significant. Therefore, the SUVmax and MTV of the primary tumor may be valuable indices to partly predict the histological type and grade of differentiation of NSCLC.

18F-FDG PET/CT oncologic imaging at extended injection-to-scan acquisition time intervals derived from a single-institution 18F-FDG-directed surgery experience: feasibility and quantification of 18F-FDG accumulation within 18F-FDG-avid lesions and background tissues

Background

¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) is a well-established imaging modality for a wide variety of solid malignancies. Currently, only limited data exists regarding the utility of PET/CT imaging at very extended injection-to-scan acquisition times. The current retrospective data analysis assessed the feasibility and quantification of diagnostic ¹⁸F-FDG PET/CT oncologic imaging at extended injection-to-scan acquisition time intervals.

Methods

¹⁸F-FDG-avid lesions (not surgically manipulated or altered during ¹⁸F-FDG-directed surgery, and visualized both on preoperative and postoperative ¹⁸F-FDG PET/CT imaging) and corresponding background tissues were assessed for ¹⁸F-FDG accumulation on same-day preoperative and postoperative ¹⁸F-FDG PET/CT imaging. Multiple patient variables and ¹⁸F-FDG-avid lesion variables were examined.

Results

For the 32 ¹⁸F-FDG-avid lesions making up the final ¹⁸F-FDG-avid lesion data set (from among 7 patients), the mean injection-to-scan times of the preoperative and postoperative ¹⁸F-FDG PET/CT scans were 73 (±3, 70-78) and 530 (±79, 413-739) minutes, respectively (P < 0.001). The preoperative and postoperative mean ¹⁸F-FDG-avid lesion SUV_max values were 7.7 (±4.0, 3.6-19.5) and 11.3 (±6.0, 4.1-29.2), respectively (P < 0.001). The preoperative and postoperative mean background SUV_max values were 2.3 (±0.6, 1.0-3.2) and 2.1 (±0.6, 1.0-3.3), respectively (P = 0.017). The preoperative and postoperative mean lesion-to-background SUV_max ratios were 3.7 (±2.3, 1.5-9.8) and 5.8 (±3.6, 1.6-16.2), respectively, (P < 0.001).

Conclusions

¹⁸F-FDG PET/CT oncologic imaging can be successfully performed at extended injection-to-scan acquisition time intervals of up to approximately 5 half-lives for ¹⁸F-FDG while maintaining good/adequate diagnostic image quality. The resultant increase in the ¹⁸F-FDG-avid lesion SUV_max values, decreased background SUV_max values, and increased lesion-to-background SUV_max ratios seen from preoperative to postoperative ¹⁸F-FDG PET/CT imaging have great potential for allowing for the integrated, real-time use of ¹⁸F-FDG PET/CT imaging in conjunction with ¹⁸F-FDG-directed interventional radiology biopsy and ablation procedures and ¹⁸F-FDG-directed surgical procedures, as well as have far-reaching impact on potentially re-shaping future thinking regarding the “most optimal” injection-to-scan acquisition time interval for all routine diagnostic ¹⁸F-FDG PET/CT oncologic imaging.

Meta-analysis of 18FDG PET-CT for nodal staging in patients with esophageal cancer

BACKGROUND

We aimed to evaluate the value of (18)FDG PET-CT for detection of regional nodal metastasis in patients with esophageal cancer before surgery.

METHODS

A computer search about PET-CT original articles was conducted from January 2000 to December 2012. The reference standard was histopathologic analysis. Two reviewers independently searched articles and extracted data. Sensitivity, specificity, diagnostic odds ratio, and likelihood ratio were pooled for PET-CT using bivariate models. Summary receiver operating characteristic (SROC) curves were also used to summarize overall test performance.

RESULTS

Across all seven studies on a per-station analysis (2232 stations), the pooled sensitivity and specificity with 95% confidence interval for PET-CT were 0.62 (0.40-0.79) and 0.96 (0.93-0.98). Across all 6 studies on a per-patient analysis (245 patients), corresponding values for PET-CT were 0.55 (0.34-0.74) and 0.76 (0.66-0.83).

CONCLUSIONS

(18)FDG PET-CT had lower sensitivity and accuracy for detection of regional nodal metastasis in patients with esophageal cancer before surgery.

Performance of whole-body PET/CT for the detection of distant malignancies in various cancers: a systematic review and meta-analysis

At present, there is no ideal imaging modality for the diagnosis of distant metastases and second primary cancers in cancer patients. We aimed to assess the accuracy of whole-body PET/CT for the overall assessment of distant malignancies in patients with various cancers.

METHODS

Studies about whole-body PET/CT for the detection of distant malignancies in cancer patients were systematically searched in MEDLINE and EMBASE. We determined sensitivities and specificities across studies, calculated positive and negative likelihood ratios, and constructed summary receiver operating characteristic curves using hierarchical regression models for whole-body PET/CT.

RESULTS

Across 41 studies (4,305 patients), the sensitivity and specificity of whole-body PET/CT were 0.93 (95% confidence interval [CI], 0.88-0.96) and 0.96 (95% CI, 0.95-0.96), respectively. Subgroup analysis showed that the sensitivity and specificity of whole-body PET/CT for various cancers, respectively, were as follows: head and neck cancer, 0.90 (95% CI, 0.83-0.95) and 0.95 (95% CI, 0.94-0.96); lung cancer, 0.91 (95% CI, 0.76-0.97) and 0.96 (95% CI, 0.94-0.98); breast cancer, 0.97 (95% CI, 0.93-0.99) and 0.95 (95% CI, 0.90-0.97); and cancer of digestive system, 0.92 (95% CI, 0.68-0.98) and 0.97 (95% CI, 0.91-0.99).

CONCLUSION

Whole-body PET/CT has excellent diagnostic performance for the overall assessment of distant malignancies in patients with various cancers, especially head and neck cancer, breast cancer, and lung cancer.