Performance of (18)F-FDG PET/CT as a postoperative surveillance imaging modality for asymptomatic advanced gastric cancer patients

Korean Practice Guidelines for Gastric Cancer 2024: An Evidence-based, Multidisciplinary Approach (Update of 2022 Guideline)

Gastric cancer is one of the most common cancers in both Korea and worldwide. Since 2004, the Korean Practice Guidelines for Gastric Cancer have been regularly updated, with the 4th edition published in 2022. The 4th edition was the result of a collaborative work by an interdisciplinary team, including experts in gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology, and guideline development methodology. The current guideline is the 5th version, an updated version of the 4th edition. In this guideline, 6 key questions (KQs) were updated or proposed after a collaborative review by the working group, and 7 statements were developed, or revised, or discussed based on a systematic review using the MEDLINE, Embase, Cochrane Library, and KoreaMed database. Over the past 2 years, there have been significant changes in systemic treatment, leading to major updates and revisions focused on this area. Additionally, minor modifications have been made in other sections, incorporating recent research findings. The level of evidence and grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation system. Key factors for recommendation included the level of evidence, benefit, harm, and clinical applicability. The working group reviewed and discussed the recommendations to reach a consensus. The structure of this guideline remains similar to the 2022 version. Earlier sections cover general considerations, such as screening, diagnosis, and staging of endoscopy, pathology, radiology, and nuclear medicine. In the latter sections, statements are provided for each KQ based on clinical evidence, with flowcharts supporting these statements through meta-analysis and references. This multidisciplinary, evidence-based gastric cancer guideline aims to support clinicians in providing optimal care for gastric cancer patients.

Serum NY-ESO-1 antibody as a predictive biomarker for postoperative recurrence of gastric cancer: a multicenter prospective observational study

BACKGROUND

No reliable marker has been identified to predict postoperative recurrence of gastric cancer. We designed a clinical trial to investigate the utility of serum NY-ESO-1 antibody responses as a predictive marker for postoperative recurrence in gastric cancer.

METHODS

A multicenter prospective study was conducted between 2012 and 2021. Patients with resectable cT3-4 gastric cancer were included. Postoperative NY-ESO-1 and p53 antibody responses were serially evaluated every 3 months for 1 year in patients with positive preoperative antibody responses. The recurrence rate was assessed by the positivity of antibody responses at 3 and 12 months postoperatively.

RESULTS

Among 1001 patients, preoperative NY-ESO-1 and p53 antibody responses were positive in 12.6% and 18.1% of patients, respectively. NY-ESO-1 antibody responses became negative postoperatively in non-recurrent patients (negativity rates; 45% and 78% at 3 and 12 months, respectively), but remained positive in recurrent patients (negativity rates; 9% and 8%, respectively). p53 antibody responses remained positive in non-recurrent patients. In multivariate analysis, NY-ESO-1 antibody positivity at 3 months (P  < 0.03) and 12 months (P  < 0.001) were independent prognostic factors for a shorter recurrence-free interval.

CONCLUSIONS

Serum NY-ESO-1 antibodies may be a useful predictive marker for postoperative recurrence in gastric cancer.

CLINICAL TRIAL REGISTRATION

UMIN000007925.

Diagnostic performance of F-18 FDG PET or PET/CT for detection of recurrent gastric cancer: a systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis investigated the diagnostic performance of F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) or PET/computed tomography (PET/CT) for the detection of disease recurrence after curative resection of gastric cancer.

METHODS

The PubMed and Embase databases, from the earliest available date of indexing through November 30, 2019, were searched for studies evaluating the diagnostic performance of F-18 FDG PET or PET/CT to detect recurrent disease after gastric cancer surgery.

RESULTS

Across 17 studies (1,732 patients), the pooled sensitivity for F-18 FDG PET or PET/CT was 0.82 (95% confidence interval [CI], 0.74-0.88) with heterogeneity of I2=76.5 (p<0.001), and the specificity was 0.86 (95% CI, 0.78-0.91) with heterogeneity of I2=94.2 (p<0.001). Likelihood ratio (LR) tests gave an overall positive LR of 6.0 (95% CI, 3.6-9.7) and negative LR of 0.2 (95% CI, 0.14-0.31). The pooled diagnostic odds ratio was 29 (95% CI, 13-63). The summary receiver operating characteristic curve indicates that the area under the curve was 0.91 (95% CI, 0.88-0.93).

CONCLUSION

The current meta-analysis showed good sensitivity and specificity of F-18 FDG PET or PET/CT for detecting recurrent disease after curative resection of gastric cancer despite heterogeneity in ethnicity, recurrence rate, histology, and interpretation method.

Korean Practice Guidelines for Gastric Cancer 2022: An Evidence-based, Multidisciplinary Approach

Gastric cancer is one of the most common cancers in Korea and the world. Since 2004, this is the 4th gastric cancer guideline published in Korea which is the revised version of previous evidence-based approach in 2018. Current guideline is a collaborative work of the interdisciplinary working group including experts in the field of gastric surgery, gastroenterology, endoscopy, medical oncology, abdominal radiology, pathology, nuclear medicine, radiation oncology and guideline development methodology. Total of 33 key questions were updated or proposed after a collaborative review by the working group and 40 statements were developed according to the systematic review using the MEDLINE, Embase, Cochrane Library and KoreaMed database. The level of evidence and the grading of recommendations were categorized according to the Grading of Recommendations, Assessment, Development and Evaluation proposition. Evidence level, benefit, harm, and clinical applicability was considered as the significant factors for recommendation. The working group reviewed recommendations and discussed for consensus. In the earlier part, general consideration discusses screening, diagnosis and staging of endoscopy, pathology, radiology, and nuclear medicine. Flowchart is depicted with statements which is supported by meta-analysis and references. Since clinical trial and systematic review was not suitable for postoperative oncologic and nutritional follow-up, working group agreed to conduct a nationwide survey investigating the clinical practice of all tertiary or general hospitals in Korea. The purpose of this survey was to provide baseline information on follow up. Herein we present a multidisciplinary-evidence based gastric cancer guideline.

Accuracy of 18F-FDG PET/CT and CECT for primary staging and diagnosis of recurrent gastric cancer: A meta-analysis

Contrast-enhanced computed tomography (CECT) is commonly used for staging and diagnosing recurrent gastric cancer. Recently, 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET)/CT gained popularity as a diagnostic tool owing to advantages including dual functional and anatomical imaging, which may facilitate early diagnosis. The diagnostic performance of 18F-FDG PET/CT and CECT has been assessed in several studies but with variable results. Therefore, the present meta-analysis aimed to evaluate the accuracy of 18F-FDG PET/CT and CECT for primary TNM staging and the diagnosis of recurrent gastric cancers. A systematic search of the PubMed Central, Medline, Scopus, Cochrane and Embase databases from inception until January 2020 was performed. The Quality Assessment of Diagnostic Accuracy Study-2 tool was used to determine the quality of the selected studies. Pooled estimates of sensitivity and specificity were calculated. A total of 58 studies comprising 9,997 patients were included. Most studies had a low risk of bias. The sensitivity and specificity for nodal staging of gastric cancer were 49% (95% CI, 37-61%) and 92% (95% CI, 86-96%) for 18F-FDG PET/CT, respectively, and 67% (95% CI, 57-76%) and 86% (95% CI, 81-89%) for CECT, respectively. For metastasis staging, the sensitivity and specificity were 56% (95% CI, 40-71%) and 97% (95% CI, 87-99%) for 18F-FDG PET/CT, respectively, and 59% (95% CI, 41-75%) and 96% (95% CI, 83-99%) for CECT, respectively. For diagnosing cancer recurrence, the pooled sensitivity and specificity were 81% (95% CI, 72-88%) and 83% (95% CI, 74-89%) for 18F-FDG PET/CT, respectively, and 59% (95% CI, 41-75%) and 96% (95% CI, 83-99%) for CECT, respectively. Both 18F-FDG PET/CT and CECT were deemed highly useful for diagnosing recurrent gastric cancer due to their high sensitivities and specificities. However, these techniques cannot be used to exclude or confirm the presence of lymph node metastases or recurrent gastric cancer tumors, but can be used for the confirmation of distal metastasis.

Pattern of extragastric recurrence and the role of abdominal computed tomography in surveillance after endoscopic resection of early gastric cancer: Korean experiences

BACKGROUND

Although extragastric recurrence after endoscopic resection of early gastric cancer is rare, it is important because of its potentially fatal outcomes. We investigated the patterns of extragastric recurrence after endoscopic resection and evaluated the role of abdominal computed tomography in surveillance.

METHODS

Between July 1994 and June 2014, 4915 patients underwent endoscopic resection of early gastric cancer. Because of follow-up periods of less than 6 months and consecutive surgery within 1 year, 810 patients were excluded. Thus, 4105 patients were retrospectively reviewed.

RESULTS

The median follow-up period was 37 months (interquartile range 20-59.6 months). The overall incidence of extragastric recurrence was 0.37% (n = 15). In patients who underwent curative resection, the incidence was 0.14% (n = 5). There were three recurrences in the absolute indication group, six in the expanded indication group, and six in the beyond expanded indication group. The median time to extragastric recurrence was 17 months (interquartile range 16.5-43.2 months). Of the 15 extragastric recurrences, 11 were in the regional lymph nodes and 4 were in the liver, adrenal gland, and peritoneum. Sixty percent (9/15) of the extragastric recurrences occurred without intragastric lesions. Eleven recurrences were detected by abdominal computed tomography, and eight patients underwent curative surgery.

CONCLUSIONS

After endoscopic resection of early gastric cancer, regional lymph node recurrence is the predominant extragastric recurrence pattern, which can be detected via abdominal computed tomography and cured by rescue surgery. Abdominal computed tomography should be considered as a surveillance method, especially in patients with an expanded indication.

PET/Computed Tomography and Precision Medicine: Gastric Cancer

Gastric cancer is a disease with low survival rates and high morbidity, requiring accurate and prompt diagnosis and treatment. Although limited in the evaluation of the primary tumor as such, the metabolic information of primary tumors in an ¹⁸F-FDG PET/CT study can assist in surgical and treatment planning and differentiating gastric cancers. It detects nodal disease with good specificity and positive predictive value, thus enabling appropriate therapy for individual patients. It provides valuable information about distant metastases, altering therapy decisions. It has reasonably good performance in detecting recurrent disease and in the follow-up of patients.

Fluorine-18-fluorodeoxyglucose positron emission tomography to evaluate recurrent gastric cancer after surgical resection: a systematic review and meta-analysis

We aimed to explore the diagnostic accuracy of (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) for detection of gastric cancer recurrence after surgical resection through a systematic review and meta-analysis. "PubMed", EMBASE, Web of Knowledge and Springer, from the beginning of 2002 to Feb 2015, were searched for studies evaluating the diagnostic performance of 18F-FDG PET in detecting recurrent gastric cancer. We calculated sensitivities, specificities, diagnostic odds ratios and likelihood ratios, and constructed summary receiver operating characteristic curves. Fourteen studies (828 patients) were included. On a per-patient basis, the forest plots showed that the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio of (18)F-FDG PET or PET/CT were 0.85 [95 % confidence interval (CI) 0.75-0.92], 0.78 (95 % CI 0.72-0.84), 3.9 (95 % CI 2.9-5.4), 0.19 (95 % CI 0.11-0.34), and 21 (95 % CI 9-47), respectively. On a per-lesion basis, the pooled sensitivity was 0.75 (95 % CI 0.61-0.86). The area under the SROC curve of PET/CT on the basis of per-patient was 0.86. (18)F-FDG PET had great value in the detection of gastric cancer recurrence after surgical resection. The sensitivities of (18)F-FDG PET were 85 and 75 %, respectively, on per-patient basis and on per-lesion basis.

Diagnostic performance of FDG PET/CT for surveillance in asymptomatic gastric cancer patients after curative surgical resection

PURPOSE

The present study evaluated the diagnostic performance of 2-[(18)F] fluoro-2-deoxy-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) for surveillance in asymptomatic gastric cancer patients after curative surgical resection.

METHODS

We retrospectively recruited 190 gastric cancer patients (115 early gastric cancer patients and 75 advanced gastric cancer patients) who underwent 1-year (91 patients) or 2-year (99 patients) postoperative FDG PET/CT surveillance, along with a routine follow-up program, after curative surgical resection. All enrolled patients were asymptomatic and showed no recurrence on follow-up examinations performed before PET/CT surveillance. All PET/CT images were visually assessed and all abnormal findings on follow-up examinations including FDG PET/CT were confirmed with histopathological diagnosis or clinical follow-up.

RESULTS

During follow-up, 19 patients (10.0 %) developed recurrence. FDG PET/CT showed abnormal findings in 37 patients (19.5 %). Among them, 16 patients (8.4 %) were diagnosed as cancer recurrence. Of 153 patients without abnormal findings on PET/CT, three patients were false-negative and diagnosed as recurrence on other follow-up examinations. The sensitivity, specificity, positive predictive value, and negative predictive value of FDG PET/CT were 84.2 %, 87.7 %, 43.2 %, and 98.0 %, respectively. Among 115 early gastric cancer patients, PET/CT detected recurrence in four patients (3.5 %) and one patient with local recurrence. Among 75 advanced gastric cancer patients, PET/CT detected recurrence in 12 patients (16.0 %), excluding two patients experiencing peritoneal recurrence. In addition, FDG PET/CT detected secondary primary cancer in six (3.2 %) out of all the patients.

CONCLUSIONS

Post-operative FDG PET/CT surveillance showed good diagnostic ability for detecting recurrence in gastric cancer patients. FDG PET/CT could be a useful follow-up modality for gastric cancer patients, especially those with advanced gastric cancer. However, further careful evaluation is needed because of false-positive findings on PET/CT.