Fluorine-18-fluorodeoxyglucose positron emission tomography to evaluate recurrent gastric cancer after surgical resection: a systematic review and meta-analysis. Ann Nucl Med. 2016;30:179-187. [PMID: 26830546 DOI: 10.1007/s12149-016-1058-y]

Tata Memorial Centre Evidence Based Use of Nuclear medicine diagnostic and treatment modalities in cancer

ABSTRACT

PET/CT and radioisotope therapy are diagnostic and therapeutic arms of Nuclear Medicine, respectively. With the emergence of better technology, PET/CT has become an accessible modality. Diagnostic tracers exploring disease-specific targets has led the clinicians to look beyond FDG PET. Moreover, with the emergence of theranostic pairs of radiopharmaceuticals, radioisotope therapy is gradually making it's way into treatment algorithm of common cancers in India. We therefore would like to discuss in detail the updates in PET/CT imaging and radionuclide therapy and generate a consensus-driven evidence based document which would guide the practitioners of Oncology.

A novel association between Bmi-1 protein expression and the SUVmax obtained by 18F-FDG PET/CT in patients with gastric adenocarcinoma

This study aimed to examine B-cell-specific Moloney murine leukemia virus integration site 1 (Bmi-1) in gastric adenocarcinoma (GAC) and its association with the maximal standard uptake value (SUVmax) of preoperative fluorine-18-fludeoosyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT). Clinicopathological data were retrospectively collected from 60 primary GAC patients. The Bmi-1 protein expression in GAC and adjacent noncancerous tissues was examined by immunohistochemistry and western blot analysis. Pearson's correlation analysis was conducted to assess the correlation between Bmi-1 expression and the SUVmax. The Bmi-1 protein levels were significantly greater in GAC versus noncancerous tissues, and higher Bmi-1 was significantly correlated with a lower degree of tumor differentiation, higher tumor stages, more lymph node metastasis, and depth of invasion. The SUVmax value was significantly correlated with the T stage, N stage, and clinical stage, but not with age, gender, tumor size, histological differentiation degree, or Lauren classification. Moreover, a significant positive correlation between Bmi-1 and SUVmax was observed in GAC tissues. In conclusion, our findings demonstrate a novel correlation between Bmi-1 and preoperative SUVmax in GAC patients who did not receive radiotherapy, chemotherapy, or targeted treatment before surgery, and both are positively correlated with unfavorable prognostic factors and a higher grade of malignancy.

HER2-Negative Schnitzler Metastasis to the Rectum Detected Using 18 F-FDG PET/CT

ABSTRACT

Gastric carcinoma metastasis occurs via hematogenous, lymphatic, or peritoneal seeding. We describe FDG PET/CT findings of Schnitzler metastasis to the rectum in a 39-year-old woman who had radical gastrectomy for signet ring gastric adenocarcinoma 2 years prior. FDG PET/CT demonstrated increased homogeneous round activity in the inner layer of rectal wall. Occult metastases of gastric carcinoma tend to be difficult to treat and have a poor prognosis. However, in some cases, FDG PET/CT might be beneficial for early detection and diagnosis of Schnitzler metastasis.

Predicting pathological response and overall survival in locally advanced gastric cancer patients undergoing neoadjuvant chemotherapy: the role of PET/computed tomography

BACKGROUND

Gastric cancer is the second leading cause of cancer-related deaths, with a 5-year survival rate of about 20-25%. The ability to predict pathological response (PR) to neoadjuvant chemotherapy (NACT); hence, overall survival (OS) probability of patients can allow the clinician to individualize treatment strategies. We investigated the role of F-18 fluorodeoxyglucose PET-computed tomography (F-18 FDG PET/CT) in predicting histopathologic response and prognosis in locally advanced gastric cancer (LAGC) patients undergoing NACT.

METHODS

F-18FDG PET/CT images taken before and after NACT, adenocarcinoma histopathology and operation pyesis reports of 43 LAGC patients were analyzed. Maximum (SUVmax) and mean (SUVmean) standardized uptake values, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of lesions were measured before and after NACT. Changes in percentage were calculated for ΔSUVmax%, ΔSUVmean%, ΔMTV%, ΔTLG%, and cutoff values were determined by receiver operating characteristic curve analysis. NACT response in pathology pyesis was determined according to the College of American Pathologists classification. PR and OS were analyzed with Kaplan-Meier and Cox proportional hazards regression models based on cutoffs found with PET measurements.

RESULTS

Cutoffs were ΔSUVmax = 33.31%, ΔSUVmean = 42.96%, ΔMTV = 30.38%, and ΔTLG = 28.14%, and all patients showed significance in PR and OS based on these cutoffs (all P < 0.01). PET/CT findings before and after NACT (ΔMTV > 30.38%, ΔTLG > 28.14%) predicted PR with 100% sensitivity and specificity. Multivariate analysis showed ΔSUVmean as an independent risk factor predicting OS (hazard ratio 0.348, 95% confidence interval 2.91-22.3, P = 0.03).

CONCLUSIONS

Metabolic parameters obtained with F-18 FDG PET/CT scanning before and after NACT in LAGC patients can accurately predict PR and OS.

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.

Value of regular endosonography and [18F]fluorodeoxyglucose PET-CT after surgery for gastro-oesophageal junction, stomach or pancreatic cancer

BACKGROUND

Most patients undergo follow-up after surgery for cancers of the gastro-oesophageal junction, stomach or pancreas, but data to support which modalities to use and the frequency of investigation are limited.

METHODS

Patients in the EUFURO study were randomized to either visits to the outpatient clinic at 3, 6, 9, 12, 18, and 24 months after surgery (standard), or to the addition of [18F]fluorodeoxyglucose (FDG) PET-CT and endoscopic ultrasonography (EUS) with guided fine-needle aspiration biopsy to clinical assessments (intervention). Data from the intervention arm were used to analyse the diagnostic performance of endosonography or [18F]FDG PET-CT in detecting recurrences.

RESULTS

During the scheduled follow-up, 42 of 89 patients developed recurrence; PET-CT and EUS in combination detected 38 of these recurrences. EUS detected 23 of the 42 patients with recurrent disease during follow-up and correctly diagnosed 17 of 19 locoregional recurrences. EUS was able to detect isolated locoregional recurrence in 11 of 13 patients. In five patients, EUS was false-positive for isolated locoregional recurrence owing to missed distant metastases. PET-CT detected locoregional recurrence in only 12 of 19 patients, and isolated locoregional recurrence in only 7 of 13. False-positive PET-CT results in 23 patients led to a total of 44 futile procedures.

CONCLUSION

Accuracy in detecting recurrences by concomitant use of PET-CT and EUS was high (90 per cent). PET-CT had moderate to high sensitivity for overall recurrence detection, but low specificity. EUS was superior to PET-CT in the detection of locoregional and isolated locoregional recurrences.

FDG PET Hybrid Imaging

Molecular imaging with positron emission tomography (PET) using tumour-seeking radiopharmaceuticals has gained wide acceptance in oncology with many clinical applications. The hybrid imaging modality PET/CT (computed tomography) allows assessing molecular as well as morphologic information at the same time. Therefore, PET/CT represents an efficient tool for whole-body staging and re-staging within one imaging modality. In oncology, the glucose analogue 18-F-fluorodeoxyglucose (FDG) is the most widely used PET/CT radiopharmaceutical in clinical routine. FDG PET and FDG PET/CT have been used for staging and re-staging of tumour patients in numerous studies. This chapter will discuss the use and the main indications of FDG PET/CT in oncology with special emphasis on lung cancer, lymphoma, head and neck cancer, melanoma and breast cancer (among other tumour entities). A review of the current literature is given with respect to primary diagnosis, staging and diagnosis of recurrent disease. Besides its integral role in diagnosis, staging and re-staging of disease in oncology, there is increasing evidence that FDG PET/CT can be used for therapy response assessment (possibly influencing therapeutic management and treatment planning) by evaluating tumour control, which will also be discussed in this chapter.

Metabolic tumor burden on postsurgical PET/CT predicts survival of patients with gastric cancer

Background

The prognostic value of postoperative ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) to patients with gastric cancer remains unclear. This study aims to investigate the prognostic value of whole body (WB) metabolic tumor burden (MTB_WB) on postsurgical ¹⁸F-FDG PET/CT to patients with gastric cancer.

Methods

A total of 376 patients with surgeries-confirmed gastric cancer were enrolled. Clinicopathologic information, overall survival (OS) and MTB_WB parameters on postsurgical PET/CT, in terms of WB maximum standardized uptake value (SUV_WBmax), WB metabolic tumor volume (MTV_WB), and WB total lesion glycolysis (TLG_WB) were collected. In-between differences of patient clinicopathologic characteristics, OS and MTB_WB measurements were compared using chi-square test, Fisher’s exact test, Student’s t test or the Kaplan-Meier survival analysis. The optimal cutoffs of MTB_WB measurements were calculated through the receiver operating characteristic (ROC) curve analysis. Univariable and multivariable Cox proportional hazard regression were performed to test the predictive value of the clinicopathologic factors and MTB_WB measurements to patient survival.

Results

The PET-positive patients had significantly decreased OS based on either Kaplan-Meier survival analysis (P <  0.001) or univariable Cox regression (hazard ratio [HR] = 2.850, P <  0.001). In patients with PET-positive tumors, the associations between OS and SUV_WBmax, MTV_WB and TLG_WB were significant, both in univariable analysis (P <  0.001, P <  0.001 and P = 0.001, respectively) and in multivariable analysis (P = 0.002, P <  0.001 and P = 0.005, respectively). Patient OS among groups dichotomized by cutoffs of SUV_WBmax > 8.6, MTV_WB > 91.5 cm³, and TLG_WB > 477.6 cm³ were significantly different (P = 0.001, P <  0.001 and P = 0.001, respectively).

Conclusions

MTB_WB, in terms of SUV_WBmax, MTV_WB and TLG_WB, on postsurgical ¹⁸F-FDG PET/CT provides prognostic value to patients with gastric cancer after curative resection.

Present and future roles of FDG-PET/CT imaging in the management of gastrointestinal cancer: an update

Positron emission tomography/computed tomography (PET/CT) integrated with 2-[¹⁸F]fluoro-2-deoxy-D-glucose (FDG) is a useful tool for acquisition of both glucose metabolism and anatomic imaging data, as only a single device and one diagnostic session is required, thus opening a new field in clinical oncologic imaging. FDG-PET/CT has been successfully used for initial staging, restaging, assessment of early treatment response, evaluation of metastatic disease response, and prognostication of intestinal cancer as well as various malignant tumors. We reviewed the current status and role of FDG-PET/CT for management of patients with esophageal cancer, gastric cancer, and colorectal cancer, with focus on both its usefulness and limitations.

Gastric cancer and imaging biomarkers: Part 1 - a critical review of DW-MRI and CE-MDCT findings

Abstract

The current standard of care for gastric cancer imaging includes heterogeneity in image acquisition techniques and qualitative image interpretation. In addition to qualitative assessment, several imaging techniques, including diffusion-weighted magnetic resonance imaging (DW-MRI), contrast-enhanced multidetector computed tomography (CE-MDCT), dynamic-contrast enhanced MRI and 18F-fluorodeoxyglucose positron emission tomography, can allow quantitative analysis. However, so far there is no consensus regarding the application of functional imaging in the management of gastric cancer. The aim of this article is to specifically review two promising biomarkers for gastric cancer with reasonable spatial resolution: the apparent diffusion coefficient (ADC) from DW-MRI and textural features from CE-MDCT. We searched MEDLINE/ PubMed for manuscripts published from inception to 6 February 2018. Initially, we searched for (gastric cancer OR gastric tumour) AND diffusion weighted magnetic resonance imaging. Then, we searched for (gastric cancer OR gastric tumour) AND texture analysis AND computed tomography. We collated the results from the studies related to this query. There is evidence that: (1) the ADC is a promising biomarker for the evaluation of the aggressiveness (T and N stage), treatment response and prognosis of gastric cancer; (2) textural features are related to the degree of differentiation, Lauren classification, treatment response and prognosis of gastric cancer. We conclude that these imaging biomarkers hold promise as effective additional tools in the diagnostic pathway of gastric cancer and may facilitate the multidisciplinary work between the radiologist and clinician, and across different institutions, to provide a greater biological understanding of gastric cancer.

Key Points

• Quantitative imaging is the extraction of quantifiable features from medical images for the assessment of normal or pathological conditions and represents a promising area for gastric cancer.

• Quantitative analysis from CE-MDCT and DW-MRI allows the extrapolation of multiple imaging biomarkers.

• ADC from DW-MRI and CE- MDCT-based texture features are non-invasive, quantitative imaging biomarkers that hold promise in the evaluation of the aggressiveness, treatment response and prognosis of gastric cancer.

Value of Preoperative PET-CT in the Prediction of Pathological Stage of Gastric Cancer

BACKGROUND

Preoperative precise staging is essential for the treatment of gastric cancer (GC); however, the diagnostic accuracy of conventional modalities needs to be increased. The present study investigated the clinical value of positron emission tomography-computed tomography (PET-CT) for the staging of GC.

METHODS

This was a retrospective study of 117 patients with a clinical diagnosis of advanced GC who underwent PET-CT followed by gastrectomy. The incidence of FDG uptake in the primary tumor or lymph nodes and its relationship with clinicopathological factors, particularly pathological stage (pStage) III/IV, were examined.

RESULTS

FDG uptake in the primary tumor was noted in 83 patients (70.9%). FDG uptake in the lymph nodes was detected in 21 patients (17.9%), and its sensitivity and specificity for lymph node metastasis were 22.7 and 90.5%, respectively. Multiple logistic regression analyses showed that FDG uptake in the primary tumor (odds ratio (OR) 2.764; 95% confidence interval (CI) 1.104-7.459, p = 0.029) and that in the lymph nodes (OR 4.660; 95% CI 1.675-13.84, p = 0.003) were factors independently associated with pStage III/IV. FDG uptake in the primary tumor detected pStage III/IV with higher sensitivity (80.4%) and that in lymph nodes found pStage III/IV with higher specificity (88.7%) than those of upper endoscopy plus CT (60.9 and 67.6%, respectively).

CONCLUSIONS

PET-CT appears to be a useful complementary modality in the assessment of pStage III/IV because of the high sensitivity of FDG uptake in the primary tumor and the high specificity of FDG uptake in the lymph nodes.

Highlights of articles published in annals of nuclear medicine 2016

This article is the first installment of highlights of selected articles published during 2016 in the Annals of Nuclear Medicine, an official peer-reviewed journal of the Japanese Society of Nuclear Medicine. A companion article highlighting selected articles published during 2016 in the European Journal of Nuclear Medicine and Molecular Imaging, which is the official peer-reviewed journal of the European Association of Nuclear Medicine, will also appear in the Annals Nuclear Medicine. This new initiative by the respective journals will continue as an annual endeavor and is anticipated to not only enhance the scientific collaboration between Europe and Japan but also facilitate global partnership in the field of nuclear medicine and molecular imaging.

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.

Follow-up after curative resection for gastric cancer: Is it time to tailor it?

There is still no consensus on the follow-up frequency and regimen after curative resection for gastric cancer. Moreover, controversy exists regarding the utility of follow-up in improving survival, and the recommendations of experts and societies vary considerably. The main reason to establish surveillance programs is to diagnose tumor recurrence or metachronous cancers early and to thereby provide prompt treatment and prolong survival. In the setting of gastric malignancies, other reasons have been put forth: (1) the detection of adverse effects of a previous surgery, such as malnutrition or digestive sequelae; (2) the collection of data; and (3) the identification of psychological and/or social problems and provision of appropriate support to the patients. No randomized controlled trials on the role of follow-up after curative resection of gastric carcinoma have been published. Herein, the primary retrospective series and systematic reviews on this subject are analyzed and discussed. Furthermore, the guidelines from international and national scientific societies are discussed. Follow-up is recommended by the majority of institutions; however, there is no real evidence that follow-up can improve long-term survival rates. Several studies have demonstrated that it is possible to stratify patients submitted to curative gastrectomy into different classes according to the risk of recurrence. Furthermore, promising studies have identified several molecular markers that are related to the risk of relapse and to prognosis. Based on these premises, a promising strategy will be to tailor follow-up in relation to the patient and tumor characteristics, molecular marker status, and individual risk of recurrence.

Surveillance for Gastric Cancer

This article discusses the current National Comprehensive Cancer Network guidelines and other available Western and Eastern guidelines for the surveillance of gastric cancer following surgical resection. It reviews the literature assessing the utility of intensive surveillance strategies for gastric cancer, which fails to show an improvement in survival. The unique issues relating to follow-up of early gastric cancer and after endoscopic resection of early gastric cancer are discussed. This article also reviews the available modalities for follow-up. In addition, it briefly discusses the advancements in treatment of recurrent and metastatic disease and the implications for gastric cancer survival and surveillance strategies.