Diagnosis and evaluation of gastric cancer by positron emission tomography

Role of PET/Computed Tomography in Gastric and Colorectal Malignancies

This article focuses on the role of PET/computed tomography in evaluating and managing gastric cancer and colorectal cancer. The authors start with describing the common aspects of imaging with 2-deoxy-2-18F-d-glucose, followed by tumor-specific discussions of gastric and colorectal malignancies. Finally, the authors provide a brief overview of non-FDG tracers including their potential clinical applications, and describe future directions in imaging these malignancies.

Application of CD34 expression combined with three-phase dynamic contrast-enhanced computed tomography scanning in preoperative staging of gastric cancer

BACKGROUND

Accurate preoperative staging of gastric cancer (GC), a common malignant tumor worldwide, is critical for appropriate treatment plans and prognosis. Dynamic three-phase enhanced computed tomography (CT) scanning for preoperative staging of GC has limitations in evaluating tumor angiogenesis. CD34, a marker on vascular endothelial cell surfaces, is promising in evaluating tumor angiogenesis. We explored the value of their combination for preoperative staging of GC to improve the efficacy and prognosis of patients with GC.

AIM

To explore the evaluation value of CD34 expression + dynamic three-phase enhanced CT scanning in preoperative staging of GC.

METHODS

Medical records of 106 patients with GC treated at the First People's Hospital of Lianyungang between February 2021 and January 2023 were retrospectively studied. All patients underwent three-phase dynamic contrast-enhanced CT scanning before surgery, and CD34 was detected in gastroscopic biopsy specimens. Using surgical and pathological results as the gold standard, the diagnostic results of three-phase dynamic contrast-enhanced CT scanning at different T and N stages were analyzed, and the expression of CD34-marked microvessel density (MVD) at different T and N stages was determined. The specificity and sensitivity of three-phase dynamic contrast-enhanced CT and CD34 in T and N staging were calculated; those of the combined diagnosis of the two were evaluated in parallel. Independent factors affecting lymph node metastasis were analyzed using multiple logistic regression.

RESULTS

The accuracy of three-phase dynamic contrast-enhanced CT scanning in diagnosing stages T1, T2, T3 and T4 were 68.00%, 75.00%, 79.41%, and 73.68%, respectively, and for diagnosing stages N0, N1, N2, and N3 were 75.68%, 74.07%, 85.00%, and 77.27%, respectively. CD34-marked MVD expression increased with increasing T and N stages. Specificity and sensitivity of three-phase dynamic contrast-enhanced CT in T staging were 86.79% and 88.68%; for N staging, 89.06% and 92.86%; for CD34 in T staging, 64.15% and 88.68%; and for CD34 in N staging, 84.38% and 78.57%, respectively. Specificity and sensitivity of joint diagnosis in T staging were 55.68% and 98.72%, and N staging were 75.15% and 98.47%, respectively, with the area under the curve for diagnosis improving accordingly. According to multivariate analysis, a longer tumor diameter, higher pathological T stage, lower differentiation degree, and higher expression of CD34-marked MVD were independent risk factors for lymph node metastasis in patients with GC.

CONCLUSION

With high accuracy in preoperatively determining the invasion depth and lymph node metastasis of GC, CD34 expression and three-phase dynamic contrast-enhanced CT can provide a reliable basis for surgical resection.

[68Ga]Ga-FAPI PET for the evaluation of digestive system tumors: systematic review and meta-analysis

PURPOSE

Digestive system tumors are a group of tumors with high incidence in the world nowadays. The assessment of digestive system tumor metastasis by conventional imaging seems to be unsatisfactory. [⁶⁸Ga]Ga-FAPI, which has emerged in recent years, seems to be able to evaluate digestive system tumor metastasis. We aimed to summarize the current evidence of [⁶⁸Ga]Ga-FAPI PET/CT or PET/MR for the assessment of primary tumors, lymph node metastases, and distant metastases in digestive system tumors. Besides, we also aimed to perform a meta-analysis of the sensitivity of [⁶⁸Ga]Ga-FAPI PET diagnosis to discriminate between digestive system tumors, primary lesions, and non-primary lesions (lymph node metastases and distant metastases).

MATERIALS AND METHODS

PubMed, MEDLINE and Cochrane Library databases were searched from the beginning of the database build to August 12, 2022. All studies undergoing [⁶⁸Ga]Ga-FAPI PET for the evaluation of digestive tumors were included in the screening and review. Screening and full text review was performed by 3 investigators and data extraction was performed by 2 investigators. Risk of bias was examined with the QUADAS-2 criteria. Diagnostic test meta-analysis was performed with a random-effects model.

RESULTS

A total of 541 studies were retrieved. Finally, 22 studies were selected for the systematic review and 18 studies were included in the meta-analysis. In the 18 publications, a total of 524 patients with digestive system tumors, 459 primary tumor lesions of digestive system tumors, and 1921 metastatic lesions of digestive system tumors were included in the meta-analysis. Based on patients, the sensitivity of [⁶⁸Ga]Ga-FAPI PET for the diagnosis of digestive system tumors was 0.98 (95% CI: 0.94-0.99). Based on lesions, the sensitivity of [⁶⁸Ga]Ga-FAPI PET for the diagnostic evaluation of primary tumor lesions of the digestive system was 0.97 (95% CI: 0.93-0.99); the sensitivity of [⁶⁸Ga]Ga-FAPI PET for the diagnostic evaluation of non-primary lesions (lymph node metastases and distant metastases) of the digestive system tumors was 0.94 (95% CI: 0.79-0.99).

CONCLUSION

[⁶⁸Ga]Ga-FAPI PET has high accuracy and its sensitivity is at a high level for the diagnostic evaluation of digestive system tumors. Clinicians, nuclear medicine physicians, and radiologists may consider using [⁶⁸Ga]Ga-FAPI PET/CT or PET/MR in the evaluation of primary tumors, lymph node metastases, and distant metastases in digestive system tumors.

Utility of [68Ga]FAPI-04 and [18F]FDG dual-tracer PET/CT in the initial evaluation of gastric cancer

Objectives

We aimed to investigate the role of [68Ga]FAPI-04 and [18F]FDG dual-tracer PET/CT for the initial assessment of gastric cancer and to explore the factors associated with their uptake.

Methods

This study enrolled 62 patients with histopathologically confirmed gastric cancer. We compared the diagnostic performance of [68Ga]FAPI-04, [18F]FDG, and combined dual-tracer PET/CT. The standardized uptake value (SUV) and tumor-to-background ratio (TBR) were also measured, and the factors that influence tracer uptake were analyzed.

Results

[68Ga]FAPI-04 PET/CT detected more primary lesions (90.3% vs 77.4%, p = 0.008) and peritoneal metastases (91.7% vs 41.7%, p = 0.031) and demonstrated higher SUVmax and TBR values (p < 0.001) of primary lesions compared to [18F]FDG PET/CT. Dual-tracer PET/CT significantly improved the diagnostic sensitivity for the detection of distant metastases, compared with stand-alone [18F]FDG (97.1% vs 73.5%, p = 0.008) or [68Ga]FAPI-04 (97.1% vs 76.5%, p = 0.016) PET/CT. Subsequently, treatment strategies were changed in nine patients following [68Ga]FAPI-04 and [18F]FDG dual-tracer PET/CT. Nevertheless, [68Ga]FAPI-04 uptake was primarily influenced by the size and invasion depth of the tumor. Both [68Ga]FAPI-04 and [18F]FDG PET/CT showed limited sensitivity for detecting early gastric cancer (EGC) (37.5% vs 25.0%, p > 0.05).

Conclusions

In this initial study, [68Ga]FAPI-04 and [18F]FDG dual-tracer PET/CT were complementary and improved sensitivity for the detection of distant metastases pre-treatment in gastric cancer and could improve treatment stratification in the future. [68Ga]FAPI-04 had limited efficacy in detecting EGC.

Key Points

•[68Ga]FAPI-04 and[18F]FDG dual-tracer PET/CT are complementary to each other for improving diagnostic sensitivity in the initial evaluation of distant metastases from gastric cancer.

•[68Ga]FAPI-04 PET/CT showed limited sensitivity in detecting EGC.

• Need for further validation in a larger multi-centre prospective study.

Evaluation of multiple biological indicators for combined diagnosis of gastric cancer: A retrospective analysis

To assess carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), platelet distribution width (PDW), neutrophil-to-lymphocyte ratio (NLR), and platelet-lymphocyte ratio (PLR) for gastric cancer's (GC) diagnostic efficiency, and the use of receiver operating characteristic curves (ROC) combined with logistic regression to evaluate multi-index combination's diagnostic value of GC. 773 GC patients' clinical data were retrospectively collected in the Weihai Municipal Hospital, affiliated hospital of Shandong University from April 2018 to May 2021, and selected 2368 healthy physical examination patients during the same period as the control group. A total of 3141 samples was included in this study, including 773 cases in the GC group and 2368 cases in the healthy physical examination group. The results of the overall comparison between groups showed that apart from gender, the age differences, CEA, CA19-9, PDW, NLR, and PLR were statistically significant (P < .001). Spearman ranks correlation analysis's results showed that CA19-9, CEA, PLR, and NLR were correlated with GC patients' clinical-stage positively, and the correlation coefficients r was 0.249, 0.280, 0.252, 0.262 (all P < .001), and PDW was correlated with the clinical stage negatively (r = -0.186, P < .001). The ROC curve analysis results of CEA, CA19-9, PDW, NLR and PLR showed that CEA's diagnostic cutoff value for GC was 3.175 (area under the curve [AUC] = 0.631, 95% CI: 0.606-0.655, P < .001), the CA19-9's diagnostic cutoff value is 19.640 (AUC = 0.589, 95% CI: 0.563-0.615, P < .001), PDW's diagnostic cutoff value is 15.750 (AUC = 0.799, 95% CI: 0.778-0.820, P < .001), NLR's diagnostic cutoff value was 2.162 (AUC = 0.699, 95% CI: 0.675-0.721, P < .001), and PLR's diagnostic cutoff value was 149.540 (AUC = 0.709, 95% CI: 0.688-0.732, P < .001). The area under the ROC curve for the combined diagnosis of GC with 5 indicators was 0.877 (95% CI: 0.860-0.894, P < .001), which was better than a single indicator (P < .05). The diagnostic efficiency of combined detection of CEA, CA19-9, PDW, NLR, and PLR is better than that of single index detection alone, which can reduce the misdiagnosis rate of GC effectively.

Severe Gastritis Due to Nivolumab Treatment of a Metastatic Melanoma Patient

Nivolumab, an anti-PD-1 check point inhibitor, is an immunotherapeutic agent, representing a major step in the treatment of melanoma. However, its use is associated with severe toxicities. Among them, gastrointestinal (GI) disorders from the lower GI tract have been widely reported. On the contrary, disorders from the upper GI tract are rare. Such a case of delayed nivolumab induced severe gastritis in a 53-year-old Caucasian female patient suffering metastatic melanoma is described. The patient's symptoms from the upper GI tract began 4 months after nivolumab treatment initiation. The diagnosis was based on imaging, including PET/CT, endoscopical and pathological findings. The side effect was successfully treated with prolonged administration of proton pump inhibitors and corticosteroids. There are only a few cases of immune check point inhibitors (ICPis) induced upper GI tract disorders, while it seems that the symptoms from nivolumab induced upper GI tract damages appear later than those reported in the lower part. Nivolumab, among other side effects, may cause severe gastritis. Hence, this pathological entity should be included in the list of this drug's side effects.

PET/CT for Predicting Occult Lymph Node Metastasis in Gastric Cancer

A portion of gastric cancer patients with negative lymph node metastasis at an early stage eventually die from tumor recurrence or advanced metastasis. Occult lymph node metastasis (OLNM] is a potential risk factor for the recurrence and metastasis in these patients, and it is highly important for clinical prognosis. Positron emission tomography (PET)/computed tomography (CT) is used to assess lymph node metastasis in gastric cancer due to its advantages in anatomical and functional imaging and non-invasive nature. Among the major metabolic parameters of PET, the maximum standardized uptake value (SUVmax) is commonly used for examining lymph node status. However, SUVmax is susceptible to interference by a variety of factors. In recent years, the exploration of new PET metabolic parameters, new PET imaging agents and radiomics, has become an active research topic. This paper aims to explore the feasibility and predict the effectiveness of using PET/CT to detect OLNM. The current landscape and future trends of primary metabolic parameters and new imaging agents of PET are reviewed. For gastric cancer patients, the possibility to detect OLNM non-invasively will help guide surgeons to choose the appropriate lymph node dissection area, thereby reducing unnecessary dissections and providing more reasonable, personalized and comprehensive treatments.

PET-CT in Clinical Adult Oncology: III. Gastrointestinal Malignancies

Simple Summary

Positron emission tomography (PET), typically combined with computed tomography (CT), has become a critical advanced imaging technique in oncology. With PET-CT, a radioactive molecule (radiotracer) is injected in the bloodstream and localizes to sites of tumor because of specific cellular features of the tumor that accumulate the targeting radiotracer. The CT scan, performed at the same time, provides information to facilitate the characterization of radioactivity from deep or dense structures, and to provide detailed anatomic information. PET-CT has a variety of applications in oncology, including staging, therapeutic response assessment, restaging and surveillance. This series of six review articles provides an overview of the value, applications, and imaging interpretive strategies of PET-CT in the more common adult malignancies. The third report in this series provides a review of PET-CT imaging in gastrointestinal malignancies.

Abstract

PET-CT is an advanced imaging modality with many oncologic applications, including staging, assessment of response to therapy, restaging and longitudinal surveillance for recurrence. The goal of this series of six review articles is to provide practical information to providers and imaging professionals regarding the best use of PET-CT for specific oncologic indications, and the potential pitfalls and nuances that characterize these applications. In the third of these review articles, key tumor-specific clinical information and representative PET-CT images are provided to outline the role that PET-CT plays in the management of patients with gastrointestinal malignancies. The focus is on the use of ¹⁸F fluorodeoxyglucose (FDG), rather than on research radiopharmaceuticals under development. Many different types of gastrointestinal tumors exist, both pediatric and adult. A discussion of the role of FDG PET-CT for all of these is beyond the scope of this review. Rather, this article focuses on the most common adult gastrointestinal malignancies that may be encountered in clinical practice. The information provided here will provide information outlining the appropriate role of PET-CT in the clinical management of patients with gastrointestinal malignancies for healthcare professionals caring for adult cancer patients. It also addresses the nuances and provides interpretive guidance related to PET-CT for imaging providers, including radiologists, nuclear medicine physicians and their trainees.

FAPI PET/CT research progress in digestive system tumours

¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography has been used in clinical practice for many years. This modality is of great value for tumour diagnosis, staging, and efficacy evaluations, but it has many limitations in the diagnosis and treatment of digestive system tumours. Fibroblast activation protein is highly expressed in gastrointestinal tumours. Various isotope-labelled fibroblast activation protein inhibitors are widely used in clinical research. These inhibitors have low background uptake in the brain, liver and oral/pharyngeal mucosa and show good contrast between the tumour and background, which makes up for the lack of fluorodeoxyglucose in the diagnosis of digestive system tumours. It better displays the primary tumours, metastases and regional lymph nodes of digestive system tumours, such as oesophageal cancer, gastric cancer and liver cancer, and also provides a new method for treating these tumours. Based on this background, this article introduces the current research status of fibroblast activation protein inhibitor positron emission tomography/computed tomography in various types of digestive system malignant tumours to provide more valuable information for diagnosing and treating digestive system tumours.

Recent Advances in the Diagnosis, Staging, Treatment, and Prognosis of Advanced Gastric Cancer: A Literature Review

Gastric cancer is one of the most common cause of cancer related deaths worldwide which results in malignant tumors in the digestive tract. The only radical treatment option available is surgical resection. Recently, the implementation of neoadjuvant chemotherapy resulted in 5-year survival rates of 95% for early gastric cancer. The main reason of treatment failure is that early diagnosis is minimal, with many patients presenting advanced stages. Hence, the greatest benefit of radical resection is missed. Consequently, the main therapeutic approach for advanced gastric cancer is combined surgery with neoadjuvant chemotherapy, targeted therapy, or immunotherapy. In this review, we will discuss the various treatment options for advanced gastric cancer. Clinical practice and clinical research is the most practical way of reaching new advents in terms of patients' characteristics, optimum drug choice, and better prognosis. With the recent advances in gastric cancer diagnosis, staging, treatment, and prognosis, we are evident that the improvement of survival in this patient population is just a matter of time.

18F-Fludeoxyglucose-Positron Emission Tomography/Computed Tomography and Laparoscopy for Staging of Locally Advanced Gastric Cancer: A Multicenter Prospective Dutch Cohort Study (PLASTIC)

Importance

The optimal staging for gastric cancer remains a matter of debate.

Objective

To evaluate the value of 18F-fludeoxyglucose-positron emission tomography with computed tomography (FDG-PET/CT) and staging laparoscopy (SL) in addition to initial staging by means of gastroscopy and CT in patients with locally advanced gastric cancer.

Design, Setting, and Participants

This multicenter prospective, observational cohort study included 394 patients with locally advanced, clinically curable gastric adenocarcinoma (≥cT3 and/or N+, M0 category based on CT) between August 1, 2017, and February 1, 2020.

Exposures

All patients underwent an FDG-PET/CT and/or SL in addition to initial staging.

Main Outcomes and Measures

The primary outcome was the number of patients in whom the intent of treatment changed based on the results of these 2 investigations. Secondary outcomes included diagnostic performance, number of incidental findings on FDG-PET/CT, morbidity and mortality after SL, and diagnostic delay.

Results

Of the 394 patients included, 256 (65%) were men and mean (SD) age was 67.6 (10.7) years. A total of 382 patients underwent FDG-PET/CT and 357 underwent SL. Treatment intent changed from curative to palliative in 65 patients (16%) based on the additional FDG-PET/CT and SL findings. FDG-PET/CT detected distant metastases in 12 patients (3%), and SL detected peritoneal or locally nonresectable disease in 73 patients (19%), with an overlap of 7 patients (2%). FDG-PET/CT had a sensitivity of 33% (95% CI, 17%-53%) and specificity of 97% (95% CI, 94%-99%) in detecting distant metastases. Secondary findings on FDG/PET were found in 83 of 382 patients (22%), which led to additional examinations in 65 of 394 patients (16%). Staging laparoscopy resulted in a complication requiring reintervention in 3 patients (0.8%) without postoperative mortality. The mean (SD) diagnostic delay was 19 (14) days.

Conclusions and Relevance

This study's findings suggest an apparently limited additional value of FDG-PET/CT; however, SL added considerably to the staging process of locally advanced gastric cancer by detection of peritoneal and nonresectable disease. Therefore, it may be useful to include SL in guidelines for staging advanced gastric cancer, but not FDG-PET/CT.

Comparative Study on Diagnosis Value of Contrast-Enhanced Ultrasound and Contrast-Enhanced Computed Tomography after Treating Advanced Renal Cancer Patients with Yiqi Jiedu Decoction

OBJECTIVE

To compare and analyze the diagnosis value of contrast-enhanced ultrasound (CEUS) and contrast-enhanced computed tomography (CECT) after treating advanced renal cancer patients with Yiqi Jiedu decoction.

METHODS

The case data of 60 patients diagnosed with advanced renal cancer from January 2013 to January 2021 at the Affiliated People's Hospital of Ningbo University were retrospectively analyzed, 30 patients who accepted the conventional treatment were included in the control group, and the rest treated with Yiqi Jiedu decoction on the basis of conventional treatment were included in the study group. After treatment, patients in both groups received the CEUS and CECT examinations, the diagnosis efficacy of both examinations was evaluated with the ROC curve, and the overall survival (OS) of patients was analyzed.

RESULTS

No significant between-group differences in the general information were observed (P > 0.05); the clinical remission rate and disease control rate were not significantly different between the two groups (P > 0.05); the enhancement and attenuation, degree of enhancement, uniformity of enhancement, and pseudocapsule sign of the CEUS and CECT examinations were not remarkably different (P > 0.05); according to the results of CEUS and CECT examinations, the maximum diameters of tumor after treatment were smaller in the study group than in the control group, but with no significant between-group difference (P > 0.05); in addition, there were no obvious differences in determining the maximum diameter of tumor by CEUS and CECT (P > 0.05), and the results of the maximum diameter of tumor determined by CEUS, CECT, and pathological specimen were not statistically different (P > 0.05); as for the diagnosis efficacy, the result was CEUS + CECT > CEUS > CECT; and the OS of patients in the study group was longer than those in the control group.

CONCLUSION

The patients treated with Yiqi Jiedu decoction obtain longer OS, and the application value of CEUS combined with CECT in the treatment effect and prognosis of patients with advanced renal cancer is higher.

Influence of Baseline Positron Emission Tomography in Metastatic Gastroesophageal Cancer on Survival and Response to Therapy

BACKGROUND

The value of baseline fluorodeoxyglucose-positron emission tomography-computed tomography (PET-CT) remains uncertain once gastroesophageal cancer is metastatic. We hypothesized that assessment of detailed PET-CT parameters (maximum standardized uptake value [SUVmax] and/or total lesion glycolysis [TLG]), and the extent of metastatic burden could aid prediction of probability of response or prognosticate.

METHODS

We retrospectively analyzed treatment-naive patients with stage 4 gastroesophageal cancer (December 2002-August 2017) who had initial PET-CT for cancer staging at MD Anderson Cancer Center. SUVmax and TLG were compared with treatment outcomes for the full cohort and subgroups based on metastatic burden (≤2 or >2 metastatic sites).

RESULTS

We identified 129 patients with metastatic gastroesophageal cancer who underwent PET-CT before first-line therapy. The median follow-up time was 61 months. The median overall survival (OS) was 18.5 months; the first progression-free survival (PFS) was 5.5 months. SUVmax or TLG of the primary tumor or of all metastases combined had no influence on OS or PFS, whether the number of metastases was ≤2 or >2. Overall response rates (ORRs) to first-line therapy were 48% and 45% for patients with ≤2 and >2 metastases, respectively (nonsignificant). ORR did not differ based on low or high values of SUVmax or TLG.

CONCLUSIONS

This is the first assessment of a unique set of PET-CT data and its association with outcomes in metastatic gastroesophageal cancer. In our large cohort of patients, detailed analyses of PET-CT (by SUVmax and/or TLG) did not discriminate any parameters examined. Thus, baseline PET-CT in untreated metastatic gastroesophageal cancer patients has limited or no utility.

Comparison of [68 Ga]Ga-FAPI-04 and [18F]-FDG for the detection of primary and metastatic lesions in patients with gastric cancer: a bicentric retrospective study

INTRODUCTION

The low sensitivity of [¹⁸F]-fluorodeoxyglucose ([¹⁸F]-FDG) for the diagnosis of gastric cancer limits its application. In this study, we aimed to investigate the potential advantage of [⁶⁸ Ga]Ga-FAPI-04 over [¹⁸F]-FDG in the evaluation of gastric cancer.

METHODS

This was a bicentric retrospective analysis of a prospective parent study (clinical trial: HS-KY-2020-826 (Huashan Hospital) and DF-2020-102 (Shanghai East Hospital)). Thirty-eight patients with gastric cancer (31 with adenocarcinoma and 7 with signet ring cell carcinoma) were included in this study. All of the participants underwent [⁶⁸ Ga]Ga-FAPI-04 and [¹⁸F]-FDG imaging by positron emission tomography (PET)/computed tomography (CT) or PET/magnetic resonance (MR). The scans were interpreted by two experienced nuclear medicine physicians, and the maximum standardized uptake value (SUV_max) was calculated. Histopathological findings obtained from biopsy or resected surgical specimens were used as a reference for the final diagnosis.

RESULTS

For the detection of primary gastric cancer, the sensitivities of [⁶⁸ Ga]Ga-FAPI-04 PET and [¹⁸F]-FDG PET were 100% (38/38) and 82% (31/38), respectively (P = 0.016). Four cases of adenocarcinoma and three cases of signet ring cell carcinoma were missed by [¹⁸F]-FDG PET. The mean SUV_max of [⁶⁸ Ga]Ga-FAPI-04 in tumours greater than 4 cm (11.0 ± 4.5) was higher than that in tumours less than 4 cm (4.5 ± 3.2) (P = 0.0015). The mean SUV_max of [⁶⁸ Ga]Ga-FAPI-04 was higher in T2-4 tumours (9.7 ± 4.4) than in T1 tumours (3.1 ± 1.5) (P = 0.0002). For the detection of metastatic lesions, the sensitivities of [⁶⁸ Ga]Ga-FAPI-04 PET and [¹⁸F]-FDG PET in 10 patients with regional lymph node metastasis and distant metastasis were 6/10 and 5/10, respectively.

CONCLUSION

In this selected cohort, [⁶⁸ Ga]Ga-FAPI-04 PET had a superior detection rate than [¹⁸F]-FDG PET for primary gastric cancer. [⁶⁸ Ga]Ga-FAPI-04 PET could provide better performance with regard to gastric cancer diagnosis and staging. Prospective clinical trials are warranted.

The New American Joint Committee on Cancer T staging system for stomach: increased complexity without clear improvement in predictive accuracy for endoscopic ultrasound

Background

The efficacy of endoscopic ultrasound (EUS) for determining the T category of gastric cancer is variable. The aim of this study was to evaluate the superiority of EUS by using the 6th edition American Joint Committee on Cancer (AJCC) staging system for stomach cancer compared to the new 7th/8th edition.

Methods

A retrospective analysis of clinical and EUS imaging features of 348 gastric carcinoma patients who underwent radical resection were retrospectively analyzed. Differences between the 6th and 7th/8th edition T staging systems for preoperative EUS evaluation were compared.

Results

The accuracy of EUS T staging was 72.4% for the 7th/8th edition and 78.4% for the 6th edition. T3 stage accuracy was significantly worse when the T3 group status was changed. The tumor location, echoendoscope type, and histological type were associated with inaccuracy. We further analyzed the EUS image features for each tumor T stage and found that an indistinctly visible muscularis propria (MP) or with obvious thickening was considered an indicator of lesions involved in the MP with a sensitivity of 81.3%; an MP completely disappeared and accompanied with a serosal layer intact may be a marker that the lesion invaded to the subserosa. We also found that irregularities in the outer edge of the gastric wall were markers of gastric serosal layer penetration with a positive predictive value of 92.2%.

Conclusions

The increased complexity of the 7th/8th edition T staging system is accompanied by worsening of the predictive accuracy for EUS as compared to the 6th edition. Furthermore, the tumor location, echoendoscope type, histological type, and EUS image features for each tumor T stage should warrant attention.

Preoperatively Treated Diffuse-Type Gastric Adenocarcinoma: Glucose vs. Other Energy Sources Substantially Influence Prognosis and Therapy Response

Simple Summary

The diffuse type of gastric adenocarcinoma (dGAC) generally confers a poor prognosis compared to intestinal type. Some dGACs are not avid on fluorine-18 fluoro-2-deoxy-D-glucose PET (FDG-PET) while others seem to consume glucose avidly. We analyzed the outcomes based on the avidity of the primary on baseline FDG-PET. Our data suggest that if dGACs used glucose as an energy source then the prognosis was very poor while non-glucose sources improved prognosis. Multi-platform (including metabolomics) profiling of dGACs would yield useful biologic understanding.

Abstract

Diffuse type of gastric adenocarcinoma (dGAC) generally confers a poor prognosis compared to intestinal type. Some dGACs are not avid on fluorine-18 fluoro-2-deoxy-D-glucose PET (FDG-PET) while others seem to consume glucose avidly. We analyzed the outcomes based on the avidity (high with standardized uptake value (SUV) > 3.5 or low with SUV ≤ 3.5) of the primary on baseline FDG-PET. We retrospectively selected 111 localized dGAC patients who had baseline FDG-PET (all were treated with preoperative chemotherapy and chemoradiation). FDG-PET avidity was compared with overall survival (OS) and response to therapy. The mean age was 59.4 years and with many females (47.7%). The high-SUV group (58 (52.3%) patients) and the low-SUV group (53 (47.7%) patients) were equally divided. While the median OS for all patients was 49.5 months (95% CI: 38.5–98.8 months), it was 98.0 months (95% CI: 49.5–NE months) for the low-SUV group and 36.0 months for the high-SUV (p = 0.003). While the median DFS for all patients was 38.2 months (95% CI: 27.7–97.6 months), it was 98.0 (95% CI: 36.9–NE months) months for the low-SUV group was and only 27.0 months (95% CI: 15.2–63.2 months) for the high-SUV group (p = 0.005). Clinical responses before surgery were more common in the low-SUV group but overall we observed only 4 pathologic complete responses in 111 patients. Our unique data suggest that if dGACs used glucose as an energy source then the prognosis was very poor while non-glucose sources improved prognosis. Multi-platform (including metabolomics) profiling of dGACs would yield useful biologic understanding.

Elevated 68Ga-FAPI Accumulation in a Recurrent Angiomyolipoma

Ga-FAPI (Ga-labeled fibroblast activation protein inhibitor) PET imaging has been recently introduced for the diagnosis and staging in various malignant tumors. However, the reports about the utility of FAPI imaging in benign tumor are relatively rare. Here we report a case of pathologically proven recurrent angiomyolipoma in the left retroperitoneal area with low F-FDG uptake but diffuse heterogeneous intense Ga-FAPI uptake together with suspected lung metastases in a 53-year-old woman. Our case illustrates FAPI imaging could be helpful not only for detecting various malignant tumors but also for benign tumor like this case due to fibrotic activity in the disease.

FKBP10 Acts as a New Biomarker for Prognosis and Lymph Node Metastasis of Gastric Cancer by Bioinformatics Analysis and in Vitro Experiments

Purpose

To explore the role of FKBP prolyl isomerase 10 (FKBP10) protein in the progression of gastric cancer.

Methods

Four independent gastric cancer databases (GSE27342, GSE29272, GSE54129 and TCGA-STAD) were used to identify differentially expressed genes (DEGs). Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis was used to identify the abnormally active pathways in patients with gastric cancer. Univariate Cox regression analysis was used to identify genes with stable prognostic value in gastric cancer patients based on three independent gastric cancer databases (GSE15459, GSE62254, TCGA-STAD). Gene set enrichment analysis (GSEA) was used to explore the possible pathways related to FKBP10. The reverse transcription-polymerase chain reaction (RT-PCR) was employed to determine the expression of FKBP10 mRNA in the HGC-27 and MKN-7 cell lines. Adhesion assay was used to detect changes in cell adhesion ability. FKBP10, ITGA1, ITGA2, ITGA5, ITGAV, ITGA6, P-AKT₄₇₃, P-AKT₃₀₈, AKT, and β-actin were evaluated by Western blot (WB).

Results

We first performed differential expression genes (DEGs) screening of four independent GC databases (GSE27342, GSE29272, GSE54129 and TCGA-STAD). Eighty-nine genes showed consistent up-regulation in GC, the results of pathway analysis showed that they were related to “Focal adhesion”. The prognostic value of these 89 genes was tested in three independent GC databases GSE15459, GSE62254 and TCGA-STAD cohort. Finally, 12 genes, in which the expression of FKBP10 was prominently increased in patients with lymph node metastasis (LNM), showed stable prognostic value. The following gene set enrichment analysis (GSEA) also showed that FKBP10 is mainly involved in cell adhesion process, while adhesion experiments confirmed that cell adhesion was down-regulated after silencing FKBP10 in GC cells, and adhesion-related molecules integrin αV and α6 were down-regulated.

Conclusion

FKBP10 may be used as a marker for lymph node metastasis of GC and could be used as a potential target for future treatment of GC.

Gastric cancer: development and validation of a CT-based model to predict peritoneal metastasis

BACKGROUND

The sensitivity of computed tomography (CT) for the detection of peritoneal metastasis (PM) of advanced gastric cancer (AGC) is relatively low.

PURPOSE

To develop a predictive model to improve the sensitivity of PM detection and to externally validate this model.

MATERIAL AND METHODS

We analyzed data from 78 patients with PM, who had undergone preoperative CT and subsequent surgery between January 2012 and December 2014, and 101 controls to form a derivation set, retrospectively. The following CT findings were evaluated: tumor size; Bormann type 4; enlarged lymph node; indirect findings of PM (peritoneal thickening, fat stranding, plaques or nodules on the peritoneum, and ascites); and definitive findings of PM (omental cake and rectal shelf). A predictive model was created using multivariate logistic regression. Receiver operating characteristic (ROC) analyses were performed to assess the diagnostic performance of the model. The accuracy was externally validated at other hospitals on 31 patients with PM and 48 patients without PM.

RESULTS

Tumor size >5.2 cm, Bormann type 4, enlarged lymph node, peritoneal plaques or nodules, and ascites were independently associated with PM. It was able to predict PM with a higher area under the ROC curve (AUC) and sensitivity than definitive findings of PM (AUC 0.903 vs. 0.647, sensitivity 92.3% vs. 38.3%). External validation confirmed the predictive power with good inter-observer agreement.

CONCLUSION

The CT-driven model shows higher AUC and sensitivity for prediction of PM and may help decision-making with the aim of improving care for patients with AGC.

Nomogram using F-18 fluorodeoxyglucose positron emission tomography/computed tomography for preoperative prediction of lymph node metastasis in gastric cancer

BACKGROUND

Lymph node (LN) metastasis is an important prognostic factor in patients with gastric cancer (GC). However, the evaluation of LN metastasis status in the preoperative setting is not accurate. Therefore, precise preoperative prediction of LN metastasis status is crucial for optimal treatment in patients with GC.

AIM

To develop a preoperative nomogram for LN metastasis using F-18 fluorodeoxyglucose (F-18 FDG) positron emission tomography/computed tomography (PET/CT) and preoperative laboratory test findings in GC.

METHODS

In this study, the data of 566 GC patients who underwent preoperative F-18 FDG PET/CT and subsequent surgical resection were analyzed. The LN metastasis prediction model was developed in the training cohort and validated in the internal validation cohort. Routine preoperative laboratory tests, including albumin and carbohydrate antigen (CA) 19-9 were performed in all patients. Univariate and multivariable logistic regression was performed to validate the preoperative predictive indicators for LN metastasis.

RESULTS

Of the 566 patients, 232 (41%) had confirmed histopathologic LN metastasis. Univariate logistic regression revealed that the tumor location, blood hemoglobin, serum albumin levels, neutrophil to lymphocyte ratio, platelet to lymphocyte ratio, CA 19-9, maximum standardized uptake value (SUVmax) of the primary tumor (T_SUVmax), and SUVmax of LN (N_SUVmax) were significantly associated with LN metastasis. In multivariate analysis, T_SUVmax (OR = 1.08; 95%CI: 1.02–1.15; P = 0.011) and N_SUVmax (OR = 1.49; 95%CI: 1.19–1.97; P = 0.002) were found to be significant predictive factors for LN metastasis. The LN metastasis prediction model using T_SUVmax, N_SUVmax, serum albumin, and CA 19-9 yielded an area under the curve (AUC) of 0.733 (95%CI: 0.683–0.784, P = 0.025) in the training cohort and AUC of 0.756 (95%CI: 0.678–0.833, P < 0.001) in the test cohort.

CONCLUSION

T_SUVmax and N_SUVmax measured by preoperative F-18 FDG PET/CT are independent predictive factors for LN metastasis in GC.

Clinical impact of FDG PET/CT in alimentary tract malignancies: an updated review

The use of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography combined with computed tomography (PET/CT) is well established in the evaluation of alimentary tract malignancies. This review of the literature and demonstration of correlative images focuses on the current role of PET/CT in the diagnosis (including pathologic/clinical staging) and post-therapy follow-up of esophageal, gastric, and colorectal cancers. PET/CT provides utility in the management of esophageal cancer, including detection of distant disease prior to resection. In gastric cancer, PET/CT is useful in detecting solid organ metastases and in characterizing responders vs. non-responders after neoadjuvant chemotherapy, the latter of which have poorer overall survival. In patients with GIST tumors, PET/CT also determines response to imatinib therapy with greater expedience as compared to CECT. For colorectal cancer, PET/CT has proven helpful in detecting hepatic and other distant metastases, treatment response, and differentiating post-radiation changes from tumor recurrence. Our review also highlights several pitfalls in PET/CT interpretation of alimentary tract lesions.

Multiple liver metastases with synchronous gastric and transverse colon cancer diagnosed by gastric perforation successfully treated by SOX plus bevacizumab and completely resected by surgery: a case report

Background

Synchronous double cancer of the colon and stomach accompanied by liver metastasis is rare. It is often difficult to determine an appropriate treatment strategy for multiple liver metastases of synchronous gastric cancer and colorectal cancer. Multidisciplinary treatment is required based on the progression and location of each tumor and chemotherapy for complete resection.

Case presentation

A 57-year-old male who complained of acute abdominal pain and fever visited his local hospital. He underwent emergent surgery for peritonitis caused by a gastric perforation. The cytodiagnosis of ascites did not show any tumor cells. There was a liver metastasis in the lateral segment of the liver. We performed a primary closure of the defect and then applied an omentum flap. After surgery, the patient was diagnosed as having synchronous cStage IV transverse colon cancer with multiple liver metastases and cStage IIB gastric cancer. The [18F]-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) showed 18F-FDG uptake by the colon tumor and multiple liver metastases, but there was no uptake in the gastric tumor or lymph nodes. We retrospectively reevaluated the CT findings from a local hospital and detected a liver nodule in segment 2/3 (from 35 to 60 mm) and segment 6 (from 26 to 57 mm), and the tumors had dramatically grown in size in only 2 months. Because complete tumor resection would be difficult, S-1 and oxaliplatin (SOX) plus bevacizumab therapy was started to control tumor progression. After 20 courses of chemotherapy, the clinical diagnosis was ycStage IV transverse colon cancer and ycStage IIa gastric cancer. We planned a two-step procedure to completely resect the primary tumors and multiple liver metastases. We first performed a laparoscopic right-colon resection+D3 lymphadenectomy and open distal gastrectomy+D2 lymphadenectomy. The patient was discharged home on postoperative day 18. After 1 month, we performed open liver resection. The pathological findings showed that the transverse colon was ypT2 (MP) with grade 2 therapeutic effects and that there were no atypical cells in the gastric tumor and multiple liver nodules (pathological complete response).

Conclusion

The SOX plus bevacizumab regimen could be an option for controlling tumor progression in synchronous double cancer of the colon and stomach with liver metastasis and led to the complete resection of such tumors.

The Utility of PET/Computed Tomography for Radiation Oncology Planning, Surveillance, and Prognosis Prediction of Gastrointestinal Tumors

At present, the strongest evidence for the use of PET/computed tomography (CT) in gastrointestinal (GI) malignancies is to rule out distant metastatic disease at diagnosis, radiation treatment planning for anal malignancies, and disease recurrence monitoring in colorectal and anal malignancies. Use of PET/CT for GI malignancies continues to evolve over time, with new studies evaluating prognostic abilities of PET/CT and with increasing sensitivity and spatial resolution of more modern PET/CT scanners. The authors encourage future applications and prospective evaluation of the use of PET/CT in the staging, prognostication, and recurrence prediction for GI malignancies.

111In-labeled anti-cadherin17 antibody D2101 has potential as a noninvasive imaging probe for diagnosing gastric cancer and lymph-node metastasis

OBJECTIVE

Cadherin-17 (CDH17) is a transmembrane protein that mediates cell-cell adhesion and is frequently expressed in adenocarcinomas, including gastric cancer. CDH17 may be an effective diagnostic marker for the staging of gastric cancer. Here, we developed an ¹¹¹In-labeled anti-CDH17 monoclonal antibody (Mab) as an imaging tracer and performed biodistribution and single-photon emission computed tomography (SPECT)/computed tomography (CT) imaging studies using mice with CDH17-positive gastric cancer xenografts. CDH17 expression in gastric cancer specimens was also analyzed.

METHODS

The cross-reactivity and affinity of our anti-CDH17 Mab D2101 was evaluated by surface plasmon resonance analysis and cell enzyme-linked immunosorbent assay, respectively. Biodistribution and SPECT/CT studies of ¹¹¹In-labeled D2101 (¹¹¹In-D2101) were performed. CDH17 expression in gastric cancer specimens was evaluated by immunohistochemistry.

RESULTS

Surface plasmon resonance analysis revealed that D2101 specifically recognizes human CDH17, but not murine CDH17. The affinity of D2101 slightly decreased as a result of the radiolabeling procedures. The biodistribution study revealed high uptake of ¹¹¹In-D2101 in tumors (maximum, 39.2 ± 9.5% ID/g at 96 h postinjection), but low uptake in normal organs, including the stomach. Temporal SPECT/CT imaging with ¹¹¹In-D2101 visualized tumors with a high degree of tumor-to-nontumor contrast. Immunohistochemical analysis revealed that, compared with HER2, which is a potential marker of N-stage, CDH17 had a higher frequency of positivity in specimens of primary and metastatic gastric cancer.

CONCLUSION

Our ¹¹¹In-anti-CDH17 Mab D2101 depicted CDH17-positive gastric cancer xenografts in vivo and has the potential to be an imaging probe for the diagnosis of primary lesions and lymph-node metastasis in gastric cancer.

Cellular magnetic resonance imaging: in vivo tracking of gastric cancer cells and detecting of lymph node metastases using microparticles of iron oxide in mice

Background

Monitoring the fate of implanted cells over time in an experimental animal may provide a new way to track the metastatic process. Lymph node metastase is of extremely importance for the prognostic prediction of gastric carcinoma. The aim of this study was to assess the feasibility of magnetic resonance imaging (MRI), using micron-sized superparamagnetic iron oxide particles (MPIO), for monitoring of the fate of gastric cancer cells and detecting the migration of gastric cancer cells through the lymphatic system in a mouse model.

Methods

SGC-7901 gastric cancer cells were labeled with green fluorescent MPIO. The cells were monitored in vitro at multiple time points by staining for iron-labeled cells and by flow cytometric detection of the fluorescent MPIO. MPIO-labeled cells were implanted subcutaneously into nude mice, and cellular MRI was performed at different time points until 35 days postinjection.

Results

The potential for retention of the iron particles in vitro was evaluated. Our results showed that the labeling and uptake efficiency of MPIO reached 90.0% after 24 hrs of incubation, and a small percentage of cells that retained MPIO could be examined until 16 days after labeling. In vivo MRI-based tracking over several weeks in mice revealed regions of signal loss in the primary tumors for up to 5 weeks. Furthermore, small regions of signal void were detected in images of the inguinal lymph nodes in three mice at day 28 postinjection or later, and histological assays confirmed the presence of iron-labeled cancer cells.

Conclusion

This study supports MPIO-based cell tracking is a useful tool for monitoring the fate of gastric cancer cells in mice over time, which may facilitate progress in understanding the mechanisms of early regional lymph node micrometastases.

Primary signet ring cell carcinoma of uterine cervix and related disease: two case reports and a review

Primary signet ring cell carcinoma of uterine cervix (SRCCC) is extremely rare. We present two cases of primary SRCCC that were treated with robot-assisted laparoscopic radical hysterectomy (RALRH). Case 1 had stage IB2 cervical adenocarcinoma, in which signet ring cell (SRC) was predominant. As adjuvant chemotherapy was not successful, she twice underwent surgical excision of recurrent tumors in pararectal lymph node and periureteral space 11 months and 27 months after RALRH, respectively. There were only SRCs observed in recurrent tumors. Case 2 had stage IB1 cervical adenocarcinoma, in which SRCs were detected only in the biopsy specimen, and no relapse occurred at 15 months after RALRH. PET/CT was useful for tumor detection in both cases, and the amount of SRC components was associated with the prognostic outcome. Considering the high recurrence rate and few complications at secondary surgery, minimally invasive surgery would be preferred as the primary surgery for SRCCC.

Double Contrast-Enhanced Ultrasonography in Preoperative T Staging of Gastric Cancer: A Comparison With Endoscopic Ultrasonography

Objective: To compare the precision of double contrast-enhanced ultrasonography (DCEUS) to endoscopic ultrasonography (EUS) in preoperative T staging of gastric cancers.

Methods: This retrospective study consisted of 158 pathologically confirmed gastric cancer patients. All patients underwent DCEUS (intravenous contrast-enhanced ultrasonography combined with oral contrast-enhanced ultrasonography) and endoscopic ultrasonography (EUS) preoperatively. The histopathological findings of resected specimens were compared with the results of DCEUS and EUS retrospectively.

Results: The accuracy of DCEUS and EUS in evaluating the T staging of gastric cancer were 82.3% (T1 62.5%,T2 84.4%,T3 87.9%,T4 91.3%) and 76.6% (T1 84.4%,T2 82.2%,T3 72.4%,T4 65.2%), respectively. There were no significant differences between the methods for the overall T staging accuracy (χ² = 1.569, P = 0.210). But EUS was superior to DCEUS for T1 stage (χ² = 3.925, P = 0.048) and DCEUS was superior to EUS for T3 stage (χ² = 4.393, P = 0.036) and T4 stage (χ² = 4.600, P = 0.032).

Conclusion: DCEUS is a convenient and noninvasive method with high precision, which can be used as the primary imaging technique for advanced gastric cancer T staging. In early gastric cancer, we should prefer EUS. Two methods are complementary for assessing tumor invasion depth of gastric cancer.

Primary Gastric Lymphoma, Epidemiology, Clinical Diagnosis, and Treatment

Primary gastric lymphoma (PGL) is the most common extranodal non-Hodgkin lymphoma and represents a wide spectrum of disease, ranging from indolent low-grade marginal zone lymphoma or mucosa-associated lymphoid tissue (MALT) lymphoma to aggressive diffuse large B-cell lymphoma. The PGL is a relatively rare cancer and easily misdiagnosed due to its unspecific symptoms of the digestive tract. The medical literature and ongoing clinical trials were reviewed on the clinical presentation, diagnosis, prognosis, prevention, and treatment of PGL. Primary gastric lymphoma is an event in the course of cancer with a variable clinical presentation and a wide differential diagnosis. Chronic gastritis secondary to Helicobacter pylori (H pylori) infection has been considered a major predisposing factor for MALT lymphoma. Magnetic resonance imaging and endoscopic ultrasonography have helped in staging of these cancers. The clinical course and prognosis of this disease are dependent on histopathological subtype and stage at the time of diagnosis. A global therapeutic approach to the cure of PGL has completely changed over the past 10 years, including innovative and conservative options to reduce treatment toxicity. Due to the rarity of PGL, many aspects of this neoplasm are still controversial. The incidence of this disease is increasing, making it necessary for clinicians to understand the clinical symptoms, workup, and treatment of these lymphomas.

PET imaging in adaptive radiotherapy of gastrointestinal tumors

INTRODUCTION

Radiotherapy is a cornerstone in the multimodality treatment of several gastrointestinal (GI) tumors. Positron-emission tomography (PET) has an established role in the diagnosis, response assessment and (re-)staging of these tumors. Nevertheless, the value of PET in adaptive radiotherapy remains unclear. This review focuses on the role of PET in adaptive radiotherapy, i.e. during the treatment course and in the delineation process.

EVIDENCE ACQUISITION

The MEDLINE database was searched for the terms ("Radiotherapy"[Mesh] AND "Positron-Emission Tomography"[Mesh] AND one of the site-specific keywords, yielding a total of 1710 articles. After abstract selection, 27 papers were identified for esophageal neoplasms, 1 for gastric neoplasms, 9 for pancreatic neoplasms, 6 for liver neoplasms, 1 for biliary tract neoplasms, none for colonic neoplasms, 15 for rectal neoplasms and 12 for anus neoplasms.

EVIDENCE SYNTHESIS

The use of PET for truly adaptive radiotherapy during treatment for GI tumors has barely been investigated, in contrast to the potential of the PET-defined metabolic tumor volume for optimization of the target volume. The optimized target definition seems useful for treatment individualization such as focal boosting strategies in esophageal, pancreatic and anorectal cancer. Nevertheless, for all GI tumors, further investigation is needed.

CONCLUSIONS

In general, too little data are available to conclude on the role of PET imaging during radiotherapy for ART strategies in GI cancer. On the other hand, based on the available evidence, the use of biological imaging for target volume adaptation seems promising and could pave the road towards individualized treatment strategies.

Adjuvant chemoradiation for gastric carcinoma: State of the art and perspectives

An estimated 990,000 new cases of gastric cancer are diagnosed worldwide each year. Surgical excision, the only chance for prolonged survival, is feasible in about 20% of cases. Even after surgery, the median survival is limited to 12 to 20 months due to the frequency of locoregional and/or metastatic recurrences. This led to clinical trials associating surgery with neoadjuvant or adjuvant treatments to improve tumor control and patient survival. The most studied modalities are perioperative chemotherapy and adjuvant chemoradiotherapy. To date, evidence has shown a survival benefit for postoperative chemoradiotherapy and for perioperative chemotherapy. Phase III trials are ongoing to compare these two modalities. The aim of this review is to synthesize current knowledge about adjuvant chemoradiotherapy in the management of gastric adenocarcinoma, and to consider its prospects by integrating modern radiotherapy techniques.

Prognostic significance of interim 18 F-fluorodeoxyglucose positron emission tomography-computed tomography volumetric parameters in metastatic or recurrent gastric cancer

AIM

To evaluate the prognostic role of interim analysis of 18F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) volumetric parameters in patients with recurrent or metastatic advanced gastric cancer (AGC) treated with fluoropyrimidine-based palliative chemotherapy.

METHODS

Forty-four patients who underwent baseline and interim PET/CT scanning during palliative chemotherapy were analyzed retrospectively. Initial and change of metabolic parameters (MP) - metabolic tumor volume (MTV), tumor lesion glycolysis (TLG) and maximum and mean standardized uptake values (SUV) were measured with PET/CT. Metabolic change was measured by ∆MP (%)  =  (MP_interim  - MP_initial )/MP _initial   ×  100. Independent t-test was employed to compare values of initial, interim and change of metabolic parameters between each response group. Log-rank test was employed for univariate analysis, and multivariate analysis was performed using the Cox proportional hazards regression model to determine independently significant prognostic factors.

RESULTS

Reduced percentage values of maximum and mean SUV on interim PET/CT and initial values of volumetric parameters (MTV and TLG) were significant predicting factors to response to fluoropyrimidine-based palliative chemotherapy. The decreased percentage values of metabolic parameters as well as maximum and mean SUV with receiver operating characteristic (ROC) curve determined cut-off points were significant prognostic factors for overall survival and progression-free survival in univariate and multivariate analyses.

CONCLUSION

Measurement of metabolic decrease of volumetric parameters by interim PET/CT analysis is useful to determine the prognosis of patients with recurrent or metastatic AGC.

18-Fluorodeoxy-Glucose Positron Emission Tomography- Computed Tomography (18-FDG-PET/CT) for Gross Tumor Volume (GTV) Delineation in Gastric Cancer Radiotherapy

Purpose:

Evaluation of the 18-fluorodeoxy-glucose positron emission tomography-computed tomography (18-FDG-PET/_CT) for gross tumor volume (GTV) delineation in gastric cancer patients undergoing radiotherapy.

Methods:

In this study, 29 gastric cancer patients (17 unresectable and 7 inoperable) were initially enrolled for radical chemoradiotherapy (45Gy/25 fractions + chemotherapy based on 5 fluorouracil) or radiotherapy alone (45Gy/25 fractions) with planning based on the 18-FDG-PET/CT images. Five patients were excluded due to excess blood glucose levels (1), false-negative positron emission tomography (1) and distant metastases revealed by 18-FDG-PET/CT (3). The analysis involved measurement of metabolic tumor volumes (MTVs) performed on PET/CT workstations. Different threshold levels of the standardized uptake value (SUV) and liver uptake were set to obtain MTVs. Secondly, GTV_PET values were derived manually using the positron emission tomography (PET) dataset blinded to the computed tomography (CT) data. Subsequently, GTV_CT values were delineated using a radiotherapy planning system based on the CT scans blinded to the PET data. The referenced GTV_CT values were correlated with the GTV_PET and were compared with a conformality index (CI).

Results:

The mean CI was 0.52 (range, 0.12-0.85). In 13/24 patients (54%), the GTV_PET was larger than GTV_CT, and in the remainder, GTV_PET was smaller. Moreover, the cranio-caudal diameter of GTV_PET in 16 cases (64%) was larger than that of GTV_CT, smaller in 7 cases (29%), and unchanged in one case. Manual PET delineation (GTVPET) achieved the best correlation with GTV_CT (Pearson correlation = 0.76, p <0.0001). Among the analyzed MTVs, a statistically significant correlation with GTV_CT was revealed for MTV_10%SUVmax (r = 0.63; p = 0.0014), MTV_liv (r = 0.60; p = 0.0021), MTV_SUV2.5 (r = 0.54; p = 0.0063); MTV_20%SUVmax (r = 0.44; p = 0.0344); MTV_30%SUVmax (r = 0.44; p = 0.0373).

Conclusion:

18-FDG-PET/_CT in gastric cancer radiotherapy planning may affect the GTV delineation.

Evolving role of FDG-PET/CT in prognostic evaluation of resectable gastric cancer

Gastric cancer (GC) remains a leading cause of cancer death worldwide. Radical gastrectomy is the only potentially curative treatment, and perioperative adjuvant therapies may improve the prognosis after curative resection. Prognosis largely depends on the tumour stage and histology, but the host systemic inflammatory response (SIR) to GC may contribute as well, as has been determined for other malignancies. In GC patients, the potential utility of positron emission tomography/computed tomography (PET/CT) with the imaging radiopharmaceutical ¹⁸F-fluorodeoxyglucose (FDG) is still debated, due to its lower sensitivity in diagnosing and staging GC compared to other imaging modalities. There is, however, growing evidence that FDG uptake in the primary tumour and regional lymph nodes may be efficient for predicting prognosis of resected patients and for monitoring tumour response to perioperative treatments, having prognostic value in that it can change therapeutic strategies. Moreover, FDG uptake in bone marrow seems to be significantly associated with SIR to GC and to represent an efficient prognostic factor after curative surgery. In conclusion, PET/CT technology is efficient in GC patients, since it is useful to integrate other imaging modalities in staging tumours and may have prognostic value that can change therapeutic strategies. With ongoing improvements, PET/CT imaging may gain further importance in the management of GC patients.

Limitations in the use of 18F-FDG PET in the pre-operative staging of gastric cancer: A case series

•

Whole body PET scan is commonly used to assess treatment response, particularly chemotherapy and for disease surveillance.

•

Various factors such as tumor size and location, histological subtype, and physiological FDG uptake by normal gastric wall influence the utility of FDG-PET in the staging workup of gastric cancer.

•

The significant cost of PET scan requires that its role in the preoperative evaluation of gastric cancer be reconsidered.

Introduction

Positron emission tomography (PET) is a mainstay in the preoperative evaluation of various cancers. In gastric cancer however, its role in the initial staging remains contentious. Presented is a case series of three gastric patients wherein the use of fluorodeoxyglucose (18F-FDG) PET/CT (computer tomography) as part of the initial staging was inconsequential to treatment, demonstrating its limited role in the staging of primary gastric cancer.

Methods

We analyzed retrospective data from 12/1/2010 to 10/31/2016 of patient with gastric cancer whose initial staging included a PET/CT. Only patients 18 years and older with gastric and gastro-oesophageal junction cancers were included. The data was derived from a single institution. Management of patients involved both an academic institution and a community practice.

Results

Of the three cases reported, an FDG-avid mass with minimal FDG uptake was reported in a single case and no FDG-avid lesion was reported in the other two. Neither of the patients underwent an endoscopic ultrasound for lack of availability.

Conclusion

While various imaging studies such as endoscopic ultrasound have an established role in the initial staging, the role of FDG-PET is yet to be established and its routine use remains contentious. Based on our clinical experience and review of the literature, we believe FDG-PET/CT imaging is of limited clinical and cost effective value in the initial staging workup of gastric cancer.

Secreted frizzled-related protein 1 overexpression in gastric cancer: Relationship with radiological findings of dual-energy spectral CT and PET-CT

We explored the role of secreted frizzled-related protein 1 (sFRP1) overexpression in gastric cancer and its relationship with radiological findings from dual-energy spectral CT(DEsCT) and positron emission tomography/computed tomography (PET/CT). We established mouse metastatic models using the SGC-7901/sFRP1 gastric cancer cell line. A control group was established using the SGC-7901/vector cell line. The models were then scanned with dual-energy spectral CT and PET-CT. Subsequent analysis, including immunohistochemistry and Transferase-mediated deoxyuridine triphosphate-biotin nick end labelling (TUNEL), was performed to confirm the role of sFRP1. Transwell chamber and angiogenesis assays were conducted to verify the effect of sFRP1 in vitro. We found that the control group showed negative radiological performance with successful implantation. Concurrently, the treated group showed visible lesions, a higher FDG uptake and increasing enhancement. The immunological and histological analysis confirmed the positive radiological performance with larger size, increasing proliferation, more microvessels and less apoptosis. The angiogenic up-regulation of sFRP1 overexpression were further verified with in vitro cell models. This preliminary study demonstrates that sFRP1 overexpression in gastric cancer cells leads to increased cell proliferation and angiogenesis, which may, in turn, contribute to positive PET/CT and CT performances.

Metabolic Signature on 18F-FDG PET/CT, HER2 Status, and Survival in Gastric Adenocarcinomas

The human epidermal growth factor 2 (HER2)-overexpressing (HER2-positive [HER2+]) gastric (GC) and gastroesophageal junction adenocarcinomas (GEJC) are felt to represent a more aggressive form of disease, which may correlate to increased metabolic activity. Whether tumor SUV_max measured by ¹⁸F-FDG PET/CT could be a preoperative parameter used to predict HER2 status of GC/GEJC is unknown.

METHODS

Pathology reports of HER2+ GC/GEJC biopsies and resections from 31 patients were reviewed and compared with HER2-negative (HER2-) cases distributed evenly over the same time period. We analyzed their SUV_max intensity and then compared the HER2 status and SUV_max parameters and their association with survival.

RESULTS

After matching for age and sex, there was no difference in SUV_max between HER2+ and HER2- cases (9.7 and 8.4, respectively; P = 0.6). No difference was seen between HER2+ and HER2- cases in tumor histology (81% and 57% intestinal type, respectively; P = 0.11), size (2.6 and 3.8 cm, respectively; P = 0.12), differentiation (47% and 68% poorly differentiated, respectively; P = 0.06), or presence of lymph node metastasis (60% and 40%, respectively; P = 0.3). Although there was no difference in survival demonstrated by HER2+ and HER2- cases, there was a significant difference in survival between SUV_max above (12.2 mo) and below (30 mo) the median SUV_max (6.6, P = 0.01).

CONCLUSION

Our study shows that SUV_max is not associated with HER2 status of GC/GEJC. Independent of HER2 overexpression, patients with a high SUV_max demonstrate a worse overall survival, suggesting that metabolic signature is a better predictor of biologic tumor aggressiveness than its histologic signature.

FLT-PET/CT diagnosis of primary and metastatic nodal lesions of gastric cancer: comparison with FDG-PET/CT

PURPOSE

To examine the diagnostic performance of (18)F-fluorothymidine (FLT)-PET/CT of primary and metastatic nodal lesions of gastric cancer by comparing with (18)F-fluorodeoxyglucose (FDG)-PET/CT.

METHODS

The enrolled study population comprised 17 patients with 17 newly diagnosed gastric cancers who underwent surgery of the primary lesion and regional nodes after both FDG- and FLT-PET/CT scans. Visual detectability of the primary gastric lesions was correlated with pathological factors using the Fisher exact or Mann-Whitney U test. The sensitivity, specificity, and accuracy in detecting nodal lesions were compared between both PET/CT scans using the McNemar exact or χ (2) test.

RESULTS

Fourteen of 17 (82.4%) primary cancers were visualized by both FDG- and FLT-PET/CT scans. Although FDG or FLT visibility was not significantly associated with tumor size (p = 0.16) or histological type (p = 1.00), the 3 nonvisible lesions were pathologically early (T1) cancers. The sensitivity, specificity, and accuracy for detecting nodal metastasis were 44.8% (13/29), 98.7% (164/166), and 90.8% (177/195) for FDG-PET/CT, and 31.0% (9/29), 100% (166/166), and 89.7% (175/195) for FLT-PET/CT, respectively. No significant difference was found between the two scans in sensitivity (p = 0.13), specificity (p = 0.48), or accuracy (p = 1.00).

CONCLUSION

FLT-PET/CT may have the same diagnostic value as FDG-PET/CT for detection of primary and nodal lesions of gastric cancer.

The role of endoscopic ultrasound on the preoperative T staging of gastric cancer: A retrospective study

Endoscopic ultrasonography (EUS) is used for preoperative assessment of gastric cancer. However, recent studies suggested that EUS staging accuracy is lower than previously thought. We aimed to assess EUS efficacy and image characteristics in preoperative gastric cancer T staging.A retrospective review of clinical and imaging features of 232 gastric carcinoma patients who underwent preoperative EUS assessment of T stage was performed. Only cases with tumor-free resection margin status and no metastases were enrolled. Comparisons of preoperative EUS and postoperative histopathological stagings were also performed to identify vital EUS image features for evaluating gastric carcinoma.EUS accuracy for T staging was 64.2% (149/232) with the highest accuracy for T3 (75.0%). Enlarged lymph nodes, well differentiated histological type and Borrmann IV type were associated with diagnostic accuracy in predicting tumor invasion. Although no factors were associated with overstaging, circumferential lesions ≥1/2, signet ring cell adenocarcinoma, and Borrmann IV type had significantly higher risks of understaging. Gastric wall outer edge irregularity was also an indicator of serosal involvement with a sensitivity of 82.0%. The pancreas and colon were more frequent disease extension sites than previously predicted.Although EUS is likely the best and most accurate option that we have used to stage gastric cancer, the finding that factors including circumferential lesions, signet ring cell adenocarcinoma, and Borrmann IV type carcinoma were more frequently related to incorrect staging warrants attention.

Noninvasive detection of gastric cancer

Gastric cancer (GC) is the fifth most common cancer and the third common cause of cancer death worldwide. Endoscopy is the most effective method for GC screening, but its application is limited by the invasion. Therefore, continuous efforts have been made to develop noninvasive methods for GC detection and promising results have been reported. Here, we review the advances in GC detection by protein and nucleic acid tumor markers, circulating tumor cells, and tumor-associated autoantibodies in peripheral blood. Some potential new noninvasive methods for GC detection are also reviewed, including exhaled breath analysis, blood spectroscopy analysis and molecular imaging.

Preoperative Use of PET/CT in Patients With Colorectal and Gastric Cancer and Its Impact on Treatment Decision Making

The advantages of primary positron emission tomography–computed tomography (PET-CT) evaluation of both cancers needs to be clarified. This study aimed to investigate the efficacy of PET-CT compared with computed tomography (CT) in preoperative evaluation of colorectal and gastric cancer patients, and to determine its effects on treatment decision-making. We prospectively evaluated patients who presented with both types of cancer in our clinic between September 2008 and June 2010, using PET-CT and CT. We compared the results with histopathologic findings and determined the changing treatment strategies. In detecting local lymph node positivity, for colorectal cancer patients the sensitivity of PET-CT was 30% and that of CT was 20%; the specificities were the same (100%). For gastric cancer patients, the sensitivity of PET-CT was 38.9% and that of CT was 22%; the specificities were 100% and 83%, respectively. In detecting metastasis, for colorectal cancer patients the sensitivity of PET-CT was 80% and that of CT was 50%; the specificities were similar (100% versus 95%). For gastric cancer patients, the sensitivity of PET-CT was 72% and that of CT was 34%; the specificities were similar (95% versus 90%). In detecting liver metastasis, for colorectal cancer patients the sensitivity of PET was 75% and that of CT was 50%; the specificities were similar (100% versus 95%). For gastric cancer patients, the sensitivity of PET-CT was 57% and that of CT was 28%; the specificities were similar (95% versus 91%). PET-CT findings altered treatment decisions in 16% of patients (n = 10; 9 gastric cancer and 1 colorectal cancer). A high rate of treatment strategy alteration in gastric cancers was seen with PET-CT; its usage is preferred in colorectal cancer staging only for high-risk patients and those with equivocal findings.

Incremental diagnostic utility of gastric distension FDG PET/CT

PURPOSE

To assess the diagnostic utility of gastric distension (GD) FDG PET/CT in both patients with known gastric malignancy and those not known to have gastric malignancy but with incidental focal FDG uptake in the stomach.

METHODS

This retrospective analysis included 88 patients who underwent FDG PET/CT following GD with hyoscine N-butylbromide (Buscopan®) and water ingestion as part of routine clinical evaluation between 2004 and 2014. FDG PET/CT scans before and after GD were reported blinded to the patient clinical details in 49 patients undergoing pretreatment staging of gastric malignancy and 39 patients who underwent GD following incidental suspicious gastric uptake. The PET findings were validated by a composite clinical standard.

RESULTS

In the 49 patients undergoing pretreatment staging of gastric malignancy, GD improved PET detection of the primary tumour (from 80 % to 90 %). PET evaluation of tumour extent was concordant with endoscopic/surgical reports in 31 % (interpreter 1) and 45 % (interpreter 2) using pre-GD images and 73 % and 76 % using GD images. Interobserver agreement also improved with GD (κ = 0.29 to 0.69). Metabolic and morphological quantitative analysis demonstrated a major impact of GD in normal gastric wall but no significant effect in tumour, except a minor increase in SUV related to a delayed acquisition time. The tumour to normal stomach SUVmax ratio increased from 3.8 ± 2.9 to 9.2 ± 8.6 (mean ± SD) with GD (p < 0.0001), facilitating detection and improved assessment of the primary tumour. In 25 (64 %) of the 39 patients with incidental suspicious gastric uptake, acquisition after GD correctly excluded a malignant process. In 10 (71 %) of the remaining 14 patients with persistent suspicious FDG uptake despite GD, malignancy was confirmed and in 3 (21 %) an active but benign pathology was diagnosed.

CONCLUSION

GD is a simple way to improve local staging with FDG PET in patients with gastric malignancy. In the setting of incidental suspicious gastric uptake, GD is also an effective tool for ruling out malignancy and leads to the avoidance of unnecessary endoscopy.

Preoperative Standardized Uptake Value of Metastatic Lymph Nodes Measured by 18F-FDG PET/CT Improves the Prediction of Prognosis in Gastric Cancer

This study assessed whether preoperative maximum standardized uptake value (SUVmax) of metastatic lymph nodes (LNs) measured by F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (F-FDG PET/CT) could improve the prediction of prognosis in gastric cancer.One hundred fifty-one patients with gastric cancer and pathologically confirmed LN involvement who had undergone preoperative F-FDG PET/CT prior to curative surgical resection were retrospectively enrolled. To obtain nodal SUVmax, a transaxial image representing the highest F-FDG uptake was carefully selected, and a region of interest was manually drawn on the highest F-FDG accumulating LN. Conventional prognostic parameters and PET findings (primary tumor and nodal SUVmax) were analyzed for prediction of recurrence-free survival (RFS) and overall survival (OS). Furthermore, prognostic accuracy of survival models was assessed using c-statistics.Of the 151 patients, 38 (25%) experienced recurrence and 34 (23%) died during follow-up (median follow-up, 48 months; range, 5-74 months). Twenty-seven patients (18%) showed positive F-FDG nodal uptake (range, 2.0-22.6). In these 27 patients, a receiver-operating characteristic curve demonstrated a nodal SUVmax of 2.8 to be the optimal cutoff for predicting RFS and OS. The univariate and multivariate analyses showed that nodal SUVmax (hazard ratio [HR] = 2.71, P < 0.0001), pathologic N (pN) stage (HR = 2.58, P = 0.0058), and pathologic T (pT) stage (HR = 1.77, P = 0.0191) were independent prognostic factors for RFS. Also, nodal SUVmax (HR = 2.80, P < 0.0001) and pN stage (HR = 2.28, P = 0.0222) were independent prognostic factors for OS. A predictive survival model incorporating conventional risk factors (pT/pN stage) gave a c-statistic of 0.833 for RFS and 0.827 for OS, whereas a model combination of nodal SUVmax with pT/pN stage gave a c-statistic of 0.871 for RFS (P = 0.0355) and 0.877 for OS (P = 0.0313).Nodal SUVmax measured by preoperative F-FDG PET/CT is an independent prognostic factor for RFS and OS. Combining nodal SUVmax with pT/pN staging can improve survival prediction precision in patients with gastric cancer.