Advantages of positron emission tomography-computed tomography imaging in esophageal squamous cell carcinoma

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.

Diagnostic Performance of ¹⁸F-FDG PET and PET/CT for the Detection of Recurrent Esophageal Cancer After Treatment with Curative Intent: A Systematic Review and Meta-Analysis

The aim of this study was to assess the diagnostic performance of (18)F-FDG PET and integrated (18)F-FDG PET/CT for diagnosing recurrent esophageal cancer after initial treatment with curative intent.

METHODS

The PubMed, Embase, and Cochrane library were systematically searched for all relevant literature using the key words "(18)F-FDG PET" and "esophageal cancer" and synonyms. Studies examining the diagnostic value of (18)F-FDG PET or integrated (18)F-FDG PET/CT, either in routine clinical follow-up or in symptomatic patients in whom recurrence of esophageal cancer was suspected, were deemed eligible for inclusion. The primary outcome was the presence of recurrent esophageal cancer as determined by histopathologic biopsy or clinical follow-up. Risk of bias and applicability concerns were assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Sensitivities and specificities of individual studies were meta-analyzed using bivariate random-effects models.

RESULTS

Eight eligible studies were included for meta-analysis, comprising 486 patients with esophageal cancer who underwent (18)F-FDG PET or PET/CT after previous treatment with curative intent. The quality of the included studies assessed by the QUADAS-2 tool was considered reasonable; there were few concerns with regard to the risk of bias and applicability. Integrated (18)F-FDG PET/CT and standalone (18)F-FDG PET were used in 4 and 3 studies, respectively. One other study analyzed both modalities separately. In 4 studies, (18)F-FDG PET or PET/CT was performed as part of routine follow-up, whereas in 4 other studies the diagnostic test was performed on indication during clinical follow-up. Pooled estimates of sensitivity and specificity for (18)F-FDG PET and PET/CT in diagnosing recurrent esophageal cancer were 96% (95% confidence interval, 93%-97%) and 78% (95% confidence interval, 66%-86%), respectively. Subgroup analysis revealed no statistically significant difference in diagnostic accuracy according to type of PET scanner (standalone PET vs. integrated PET/CT) or indication of scanning (routine follow-up vs. on indication).

CONCLUSION

(18)F-FDG PET and PET/CT are reliable imaging modalities with a high sensitivity and moderate specificity for detecting recurrent esophageal cancer after treatment with curative intent. The use of (18)F-FDG PET or PET/CT particularly allows for a minimal false-negative rate. However, histopathologic confirmation of (18)F-FDG PET- or PET/CT-suspected lesions remains required, because a considerable false-positive rate is noticed.

Cks overexpression enhances chemotherapeutic efficacy by overriding DNA damage checkpoints

Cdc kinase subunit (Cks) proteins Cks1 and Cks2 are adaptor-like proteins that bind many cyclin-dependent kinases. A wealth of clinical data has shown that Cks proteins are overexpressed in many types of human cancers and this often correlates with increased tumor aggressiveness. Previously, we showed that Cks overexpression abrogates the intra-S-phase checkpoint, a major barrier to oncogene-mediated transformation. Interestingly, the intra-S-phase checkpoint is crucial for the cellular response to replication stress, a major pathway of apoptosis induction by many chemotherapeutic agents. Here, we demonstrate cancer cells that overexpress Cks1 or Cks2 override the intra-S-phase checkpoint in the presence of replication stress-inducing chemotherapies such as 5-Fluorouracil (5-FU) and methotrexate (MTX) leading to enhanced sensitivity in vitro and in vivo. Furthermore, enforced expression of Cks1 in an MTX-resistant breast cancer cell line was found to restore drug sensitivity. Our results suggest that Cks proteins are important determinants of apoptosis induction of replication stress-inducing chemotherapies such as 5-FU.

Diagnostic value of ¹⁸F-FDG PET/CT for lymph node metastasis of esophageal squamous cell carcinoma

PURPOSE

This study investigated the diagnostic accuracy of hybrid positron-emission tomography/computed tomography (PET/CT) for lymph node (LN) metastasis of esophageal cancer. We also investigated the correlation between the size of metastatic nests and the detection by PET/CT.

METHODS

Two hundred and fifty-eight patients with esophageal squamous cell carcinoma who underwent esophagectomy with two- or three-field radical lymphadenectomy were analyzed retrospectively. We compared the diagnosis of preoperative PET/CT to the postoperative histopathological examination by each anatomical field (n = 1,231) in all 258 patients. The metastatic LNs resected from PET/CT positive fields were classified as belonging to the PET/CT-N-positive group (n = 229) and those from negative fields as belonging to the PET/CT-N-negative group (n = 352). The cross-sectional areas of metastatic nests were measured in each metastatic LN.

RESULTS

Of the 1,231 fields, 275 (22 %) were positive for metastasis, including 581 LNs from 408 regional LN stations. The sensitivity and specificity of PET/CT examined by each anatomical field were 25.8 and 97.8 %, respectively. The median area of metastatic nests was 17.7 mm2 in the PET/CT-N-positive group, and 7.7 mm2 in the PET/CT-N-negative group (p < 0.001).

CONCLUSIONS

A significant correlation was suggested between the nest size and detection by PET/CT. Because of its low sensitivity, PET/CT alone is insufficient to determine the surgical procedures, especially when considering reduction surgery.

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.