Japanese Gastric Cancer Association Task Force for Research Promotion: clinical utility of ¹⁸F-fluoro-2-deoxyglucose positron emission tomography in gastric cancer. A systematic review of the literature

Hepatic resection for gastric cancer liver metastases: A systematic review and meta-analysis

BACKGROUND

Resection of liver metastases from gastric cancer (GC) is rarely performed, and the outcome after hepatic surgery has not been systematically evaluated in the literature. The aim of this study was to perform a systematic review of outcome and prognostic factors for survival after liver metastasectomy for GC.

METHODS

We performed a meta-analysis of published studies that focused on long-term outcomes (5-year overall survival [OS]) after surgical management of liver metastases from GC, and included more than 10 patients each. Pooled hazard ratios (HRs) were calculated for variables considered as potential prognostic factors for OS in at least three publications.

RESULTS

Twenty-three studies comprising a total of 870 patients were considered in this analysis. The pooled weighted median OS was 22 months (95%CI 17.6-27.2). The pooled 5-year OS after liver resection was 23.8% (95%CI 19-29.3%). The pooled 5-year OS rates for metachronous and synchronous metastases were 30% (95%CI 24.7-35.8%) and 22.6% (95%CI 14-34.4%), respectively. Parameters associated with poor survival were (i) multiple metastases, and (ii) large size of metastases.

CONCLUSIONS

Hepatic resection of GC liver metastases is associated with an acceptable 5-year OS, in particular after surgery of metachronous lesions, and could be offered to selected patients.

Risk factors associated with diagnostic discrepancy of gastric indefinite neoplasia: Who need en bloc resection?

BACKGROUND

Endoscopic forceps biopsy is insufficient for a definitive diagnosis of dysplastic lesions. It is difficult to decide clinical management of gastric indefinite neoplasia diagnosed by endoscopic forceps biopsy when early gastric cancer (EGC) is macroscopically suspected. The aim of this study was to discuss the final results of gastric indefinite neoplasia and associated clinical factors predictive of early gastric cancer.

METHODS

The medical records of 119 patients who were diagnosed with gastric indefinite neoplasia by index forceps biopsy were retrospectively reviewed. The initial endoscopic findings were analyzed, and predictive factors of EGC were evaluated.

RESULTS

The final pathologic diagnoses of 119 patients included early gastric cancer (n = 26, 21.8%), adenoma (n = 6, 5.0%) and non-neoplasm (n = 87, 73.1%). Univariate analysis showed that lesion size greater than 10 mm, surface nodularity and surface redness were associated risk factors. In the multivariate analysis, lesions diameter (p = 0.021, OR 11.401, 95% CI 1.432-90.759) and surface redness (p = 0.014, OR 3.777, 95% CI 1.306-10.923) were significant risk factors.

CONCLUSIONS

Patients with gastric indefinite neoplasia with larger size (≥10 mm) and surface redness might need further diagnostic investigation rather than simple follow-up endoscopy.

Redefining early gastric cancer

BACKGROUND

The problem is that current definitions of early gastric cancer allow the inclusion of regional lymph node metastases. The increasing use of endoscopic submucosal dissection to treat early gastric cancer is a concern because regional lymph nodes are not addressed. The aim of the study was thus to critically evaluate current evidence with regard to tumour-specific factors associated with lymph node metastases in "early gastric cancer" to develop a more precise definition and improve clinical management.

METHODS

A systematic and comprehensive search of major reference databases (MEDLINE, EMBASE, PubMed and the Cochrane Library) was undertaken using a combination of text words "early gastric cancer", "lymph node metastasis", "factors", "endoscopy", "surgery", "lymphadenectomy" "mucosa", "submucosa", "lymphovascular invasion", "differentiated", "undifferentiated" and "ulcer". All available publications that described tumour-related factors associated with lymph node metastases in early gastric cancer were included.

RESULTS

The initial search yielded 1494 studies, of which 42 studies were included in the final analysis. Over time, the definition of early gastric cancer has broadened and the indications for endoscopic treatment have widened. The mean frequency of lymph node metastases increased on the basis of depth of infiltration (mucosa 6% vs. submucosa 28%), presence of lymphovascular invasion (absence 9% vs. presence 53%), tumour differentiation (differentiated 13% vs. undifferentiated 34%) and macroscopic type (elevated 13% vs. flat 26%) and tumour diameter (≤2 cm 8% vs. >2 cm 25%).

CONCLUSION

There is a need to re-examine the diagnosis and staging of early gastric cancer to ensure that patients with one or more identifiable risk factor for lymph node metastases are not denied appropriate chemotherapy and surgical resection.

A strategy for improving FDG accumulation for early detection of metastasis from primary pancreatic cancer: stimulation of the Warburg effect in AsPC-1 cells

INTRODUCTION

Early detection and/or prediction of metastasis provide more prognostic relevance than local recurrence. Direct spread into the peritoneum is frequently found in pancreatic cancer patients, but positron emission tomography (PET) with 2-deoxy-2-fluoro-d-glucose (FDG) is not useful for identifying such metastasis. We investigated a method to enhance FDG accumulation using AsPC-1 human ascites tumor cells.

METHODS

(14)C-FDG accumulation was assessed under the following conditions: 1) characteristics of (14)C-FDG transport were examined using phloridzin, a Na(+)-free buffer, and various hexoses, and 2) accumulation of (14)C-FDG was measured in cells that were pretreated with hexose for various time periods, and activity of 6-phosphofructo-1-kinase (PFK-1) was assayed.

RESULTS

(14)C-FDG transport into AsPC-1 cells was mediated primarily by a Na(+)-independent transport mechanism. Aldohexoses such as d-glucose, D-mannose, and D-galactose inhibited (14)C-FDG transport. Cells pretreated with d-glucose, D-mannose, or D-fructose exhibited augmented (14)C-FDG accumulation. Pretreatment with higher concentrations of D-glucose or D-fructose tended to increase PFK-1 activity.

CONCLUSIONS

Very little information has been published about the association between PFK-1 and FDG accumulation, and we confirmed the impacts of various hexoses on the activity of PFK-1 and FDG accumulation in AsPC-1 cells. Clarifying the relevance of PFK-1 in FDG accumulation will contribute to developing new features of FDG-PET, because PFK-1 is the main regulator of glycolysis.

New approaches to gastric cancer staging: Beyond endoscopic ultrasound, computed tomography and positron emission tomography

Currently, there is no single gold standard modality for staging of gastric cancer and several methods have been used complementarily in the each clinical situation. To make up for the shortcomings of conventional modalities such as endoscopic ultrasound, computed tomography and ¹⁸F-fluoro-2-deoxyglucose positron emission tomography, numerous attempts with new approaches have been made for gastric cancer staging. For T staging, magnifying endoscopy with narrow-band was evaluated to differentiate mucosal cancer from submucosal cancer. Single/double contrast-enhanced ultrasound and diffusion-weighted magnetic resonance imaging were also tried to improve diagnostic accuracy of gastric cancer. For intraoperative staging with sentinel node mapping, indocyanine green infrared and fluorescence imaging was introduced. In addition, to detect micrometastasis, real-time reverse transcription-polymerase chain reaction system with multiple markers was studied. Staging laparoscopy using 5-aminolevulinic acid-mediated photodynamic diagnosis and percutaneous diagnostic peritoneal lavage were also evaluated. However, most studies reporting new staging methods is preliminary and further studies for validation in clinical practice are needed. In this mini-review, we discuss new progress in gastric cancer staging. Especially, we focus on new diagnostic approach to gastric cancer staging beyond the conventional modalities and briefly review the remarkable clinical results of the studies published over the past three years.

[18F]Fluorodeoxyglucose PET/Computed Tomography in Gastrointestinal Malignancies

This article discusses the current state-of-the-art application of 2-deoxy-2-[(18)F]fluoro-d-glucose (FDG)-PET and FDG-PET/computed tomography (CT) in the management of patients with gastrointestinal malignancies. Gastrointestinal malignancies include many different cell types, several common malignancies of which may be imaged by FDG-PET/CT. This review focuses on gastric carcinoma, pancreatic carcinoma, hepatocellular carcinoma, cholangiocarcinoma, colorectal carcinoma, and stroma cell tumors. The role of FDG-PET/CT in staging these malignancies is discussed, in addition to (re)staging, detection of recurrent disease, patient selection/prognostication, and response assessment, using the currently available literature.

Accuracy of multidetector-row CT in diagnosing lymph node metastasis in patients with gastric cancer

OBJECTIVES

The purpose of this study was to determine the optimal cut-off value of lymph node size for diagnosing metastasis in gastric cancer with multidetector-row computed tomography (MDCT) after categorizing perigastric lymph nodes into three regions.

METHODS

The study included 90 gastric cancer patients who underwent gastrectomy. The long-axis diameter (LAD) and short-axis diameter (SAD) of all visualized lymph nodes were measured with transverse MDCT images. The locations of lymph nodes were categorized into three regions: lesser curvature, greater curvature, and suprapancreatic. The diagnostic value of lymph node metastasis was assessed with receiver operating characteristic (ROC) analysis.

RESULTS

The area under the curve was larger for SAD than LAD in all groups. The optimal cut-off values of SAD were determined as follows: overall, 9 mm; differentiated type, 9 mm; undifferentiated type, 8 mm; lesser curvature region, 7 mm; greater curvature region, 6 mm; and suprapancreatic region, 9 mm. The diagnostic accuracies for lymph node metastasis using individual cut-off values were 71.1% based on histological type and 76.6% based on region of lymph node location.

CONCLUSIONS

The diagnostic accuracy of lymph node metastasis in gastric cancer was improved by using individual cut-off values for each lymph node region.

KEY POINTS

• Multidetector-row computed tomography is widely used to predict pathological nodal status. • An optimal cut-off value of lymph node size has not been determined. • Cut-off values were assessed according to histology and nodal location. • The optimal cut-off values differed based on histology and nodal location. • Diagnostic accuracy was improved by using individual cut-off values for each region.

Diagnosis and evaluation of gastric cancer by positron emission tomography

Gastric cancer is the second leading cause of cancer mortality worldwide. The diagnosis of gastric cancer has been significantly improved with the broad availability of gastrointestinal endoscopy. Effective technologies for accurate staging and quantitative evaluation are still in demand to merit reasonable treatment and better prognosis for the patients presented with advanced disease. Preoperative staging using conventional imaging tools, such as computed tomography (CT) and endoscopic ultrasonography, is inadequate. Positron emission tomography (PET), using ¹⁸F-fluorodeoxyglucose (FDG) as a tracer and integrating CT for anatomic localization, holds a promise to detect unsuspected metastasis and has been extensively used in a variety of malignancies. However, the value of FDG PET/CT in diagnosis and evaluation of gastric cancer is still controversial. This article reviews the current literature in diagnosis, staging, response evaluation, and relapse monitoring of gastric cancer, and discusses the current understanding, improvement, and future prospects in this area.

Response to chemotherapy in gastric adenocarcinoma with diffusion-weighted MRI and (18) F-FDG-PET/CT: correlation of apparent diffusion coefficient and partial volume corrected standardized uptake value with histological tumor regression grade

PURPOSE

To assess whether changes in diffusion-weighted MRI (DW-MRI) and (18) F-fluoro-2-deoxyglucose positron emission tomography/computed tomography ((18) F-FDG PET/CT), correlate with treatment response to neoadjuvant therapy (NT), as expressed by tumor regression grade (TRG), from locally advanced gastric adenocarcinoma (GA).

MATERIALS AND METHODS

Seventeen patients underwent both DW-MRI and (18) F-FDG-PET/CT scans before and after the end of NT. Apparent diffusion coefficient (ADC) and mean standardized uptake value (SUV) corrected for partial volume effect (PVC-SUVBW-mean ) were evaluated and compared with histopathological TRG.

RESULTS

Pre- and post-NT and percentage changes for ADC and PVC-SUVBW-mean were assessed. Post-NT ADC and ΔADC showed a significant inverse correlation with TRG (r = -0.71; P = 0.0011 and r = -0.78; P = 0.00020, respectively) and significant differences in their mean values were found between responders (TRG 1-2-3) and nonresponders (TRG 4-5) (P = 0.0009; P = 0.000082, respectively). No correlations with TRG were found for pre-NT ADC and for all PVC-SUVBW-mean values as well as between ΔADC and Δ PVC-SUVBW-mean .

CONCLUSION

DW-MRI seems more accurate than (18) F-FDG-PET/CT and ADC modifications may represent a reproducible tool to assess tumor response for GA.

¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography for the evaluation of bone metastasis in patients with gastric cancer

BACKGROUND

The roles of positron emission tomography and bone scanning in identifying bone metastasis in gastric cancer are unclear.

AIM

We compared the usefulness of positron emission tomography-computed tomography and scanning in detecting bone metastasis in gastric cancer.

METHODS

Data from 1485 patients diagnosed with gastric cancer who had undergone positron emission tomography-computed tomography and scanning were reviewed. Of 170 enrolled patients who were suspected of bone metastasis in either positron emission tomography or scanning, 81.2% were confirmed to have bone metastasis.

RESULTS

The sensitivity, specificity, and accuracy were 93.5%, 25.0%, and 80.6%, respectively, for positron emission tomography and 93.5%, 37.5%, and 82.9%, respectively, for scanning. 87.7% of patients with bone metastasis showed positive findings on two modalities. 15.0% of solitary bone metastases were positive on positron emission tomography only. Positron emission tomography was superior to scanning for the detection of synchronous bone metastasis, but the two modalities were similar for the detection of metachronous bone metastasis. The concordance rate of response assessment after treatment between two modalities was moderate.

CONCLUSIONS

Positron emission tomography-computed tomography may be more effective for the diagnosis of bone metastasis in the initial staging workup. Conversely, bone scanning and positron emission tomography-computed tomography may be similarly effective for the detection of metachronous bone metastasis.

Assessment of (18)F-fluorodeoxyglucose positron emission tomography combined with computed tomography in the preoperative management of patients with gastric cancer

BACKGROUND

The significance of (18)F-2-deoxy-2-fluoro-glucose positron emission tomography combined with computed tomography imaging (FDG-PET/CT) in the diagnosis of gastric cancer remains controversial. This study aimed to evaluate the efficacy of preoperative FDG-PET/CT in staging of gastric cancer.

METHODS

FDG-PET/CT results for 90 patients with gastric cancer were retrospectively examined. For quantitative PET analysis, FDG uptake was assessed based on the maximum standardized uptake values (SUVmax).

RESULTS

FDG-PET/CT detected the primary gastric cancer in 71 of the 90 patients (sensitivity 78.9 %). The median SUVmax was significantly higher in patients with T3/T4 disease than in those with T1/T2 (9.0 vs. 3.8; P < 0.001), in patients with distant metastasis than in those with no metastasis (9.5 vs. 7.7; P = 0.018), and with stage III/IV tumors than in those with stage I/II (9.0 vs. 4.7; P = 0.017). The SUVmax of the primary tumor was significantly correlated with tumor size (r = 0.461, P < 0.001). The sensitivity, specificity, and accuracy of FDG-PET/CT in assessing metastasis to regional lymph nodes were 64.5, 85.7, and 71.1 %, respectively.

CONCLUSIONS

FDG-PET/CT results are significantly associated with tumor progression in gastric cancer, and such findings can reliably identify cancer cell populations.

Detection of metastatic lymph nodes using 5-aminolevulinic acid in patients with gastric cancer

BACKGROUND

Precise diagnosis of lymph node metastases is essential to select therapeutic strategy for patients with gastric cancer, and rapid intraoperative diagnosis is useful for performing less invasive surgery. In this study, we focused on a known photosensitizer, 5-aminolevulinic acid (5-ALA), and examined the feasibility of 5-ALA-induced protoporphyrin IX (PpIX) fluorescence to detect metastatic foci in excised lymph nodes of patients with gastric cancer.

METHODS

A total of 144 lymph nodes obtained from 14 gastric cancer patients were examined. The patients were administered 5-ALA orally before surgery. Excised lymph nodes were cut in half and observed by fluorescence microscopy. The diagnostic results were compared to those of the routine histopathological examination.

RESULTS

Observed red fluorescence of PpIX was identical to the metastatic focus, with 84 % accuracy. Twelve non-metastatic lymph nodes showed unexpected PpIX accumulation to lymphoid follicles, but these could be discriminated based on their characteristic fluorescence patterns. With incorporation of this morphological consideration, this method demonstrated good diagnostic power with 92.4 % accuracy. On the quantitative analysis using the signal intensity ratio of red to the sum of red, green, and blue (R/(R + G + B) ratio) as an index corresponding to red fluorescence of PpIX, metastatic lymph nodes showed significantly higher value than non-metastatic lymph nodes (p < 0.0001). The area under the curve was calculated as 0.832 throughout Receiver operating characteristic analysis.

CONCLUSIONS

Our results demonstrated that 5-ALA-induced fluorescence diagnosis is a simple and safe method and is a potential candidate for a novel rapid intraoperative diagnostic method applicable to clinical practice.

[18F]Fluorodeoxyglucose accumulation as a biological marker of hypoxic status but not glucose transport ability in gastric cancer

Background

The use of [18F] 2-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) for detection of gastric cancer is often debated because FDG uptake varies for each patient. The purpose of this study was to clarify the molecular mechanisms involved in FDG uptake.

Material and methods

Fifty patients with gastric cancer who underwent FDG-PET and gastrectomy were studied. Snap-frozen tumor specimens were collected and examined by real-time PCR for relationships between maximum standardized uptake value (SUV) and mRNA expression of the following genes: glucose transporter 1 (GLUT1), hexokinase 2 (HK2), hypoxia-inducible factor 1α (HIF1α), and proliferating cell nuclear antigen (PCNA).

Results

Tumor size was the only clinicopathological parameter that significantly correlated with SUV. Transcripts for the genes evaluated were about three-fold higher in malignant specimens than in normal mucosa, although only HIF1α was significantly correlated with SUV. When divided into intestinal and non-intestinal tumors, there was a significant correlation between SUV and tumor size in intestinal tumors. Interestingly, the weak association between SUV and HIF1α expression in intestinal tumors was substantially stronger in non-intestinal tumors. No correlation was found between SUV and mRNA expression of other genes in intestinal or non-intestinal tumors.

Conclusion

SUV was correlated with HIF1α, but not PCNA, HK2, or GLUT1 expression. FDG accumulation could therefore represent tissue hypoxia rather than glucose transport activity for aggressive cancer growth.

F-18 fluorodeoxyglucose positron emission tomography/computed tomography in the staging of linitis plastica caused by primary gastric adenocarcinoma

Diffuse infiltration by a primary or metastatic malignancy into the submucosa and muscularis of the stomach (linitis plastica [LP]) has been described in literature. The authors present a case of LP caused by primary adenocarcinoma of the stomach, showing diffuse Fluorine-18 fluorodeoxyglucose uptake in the thickened wall of the stomach.

Apparent diffusion coefficient modifications in assessing gastro-oesophageal cancer response to neoadjuvant treatment: comparison with tumour regression grade at histology

OBJECTIVES

To assess changes in apparent diffusion coefficient (ΔADC) and volume (ΔV) after neoadjuvant treatment (NT), and tumour regression grade (TRG) in gastro-oesophageal cancers (GEC), and to discriminate responders from non-responders.

METHODS

Thirty-two patients with biopsy-proven locally-advanced GEC underwent diffusion weighted magnetic resonance imaging (DWI) pre- and post-NT. Lesion ADC, volume, ΔADC and ΔV were calculated. TRG 1-2-3 patients were classified as R; TRG 4-5 as non-responders. ΔADC-TRG and ΔV-TRG correlations, pre-NT and post-NT ADC, ΔADC and ΔV cut-off values for responders and non-responders were calculated. Two readers measured mean tumour ADCs and interobserver variability was calculated. (Spearman's and intraclass correlation coefficient [ICC]).

RESULTS

The interobserver reproducibility was very good both for pre-NT (Spearman's rho = 0.8160; ICC = 0.8993) and post-NT (Spearman's rho = 0.8357; ICC = 0.8663). Responders showed lower pre-NT ADC (1.32 versus 1.63 × 10(-3) mm(2)/s; P = 0.002) and higher post-NT ADC (2.22 versus 1.51 × 10(-3) mm(2)/s; P = 0.001) than non-responders and ADC increased in responders (ΔADC, 85.45 versus -8.21 %; P = 0.00005). ΔADC inversely correlated with TRG (r = -0.71, P = 0.000004); no difference in ΔV between responders and non-responders (-50.92 % versus -14.12 %; P = 0.068) and no correlation ΔV-TRG (r = 0.02 P = 0.883) were observed.

CONCLUSIONS

The ADC can be used to assess gastro-oesophageal tumour response to neoadjuvant treatment as a reliable expression of tumour regression.

KEY POINTS

• DWI is now being used to assess many cancers. • Change in ADC measurements offer new information about oesophageal tumours. • ADC changes are more reliable than dimensional criteria in assessing neoadjuvant treatment. • Such ADC assessment could optimise management of locally advanced gastro-oesophageal cancers.

Gastric cancers with microsatellite instability exhibit high fluorodeoxyglucose uptake on positron emission tomography

BACKGROUND

Gastric cancers exhibit various degrees of (18)F-fluorodeoxyglucose (FDG) uptakes on positron emission tomography/computed tomography (PET/CT) imaging. The aim of this study was to evaluate whether FDG uptake in gastric cancer varies according to the microsatellite instability (MSI) status.

METHODS

Consecutive gastric cancer patients who underwent PET/CT imaging and MSI analysis were included in the study. The maximum standardized uptake value (SUVmax) of gastric cancer was assessed using PET/CT imaging.

RESULTS

Of 131 gastric cancers, 16 exhibited a high incidence of MSI (MSI-H) and 3 exhibited a low incidence of MSI (MSI-L). In 29 subjects who showed no uptake on PET/CT imaging the gastric cancers were all microsatellite stable (MSS). Gastric cancers with MSI were related to age older than 60 years (p = 0.002), cancer volume larger than 10 cm(3) (p = 0.015), and the presence of FDG uptake on PET/CT imaging (p = 0.001). A higher SUVmax of gastric cancer was linked to the presence of MSI (p < 0.001).

CONCLUSION

The presence of MSI is related to FDG uptake in gastric cancer. Care should be taken with MSS gastric cancers, because they show lower SUVmax on PET/CT imaging than MSI gastric cancers.

18F-FDG PET-CT for detecting recurrent gastric adenocarcinoma: results from a Non-Oriental Asian population

OBJECTIVE

To evaluate the utility of fluorine-18 fluorodeoxyglucose (18F-FDG) PET-CT in the diagnosis of recurrent gastric adenocarcinoma in a Non-Oriental Asian population.

METHODS

In this retrospective analysis, data from 72 Non-Oriental Asian patients, who underwent 93 18F-FDG PET-CT studies, were evaluated. All patients had histopathologically proven gastric adenocarcinoma, for which they had undergone primary treatment. PET-CT was performed for suspected recurrence or for post-therapy surveillance. PET-CT findings were analysed on a per-patient and per-region basis (local/lymph node/liver/lung/bone/others). A combination of clinical follow-up (minimum 6 months; range: 6-36 months), imaging follow-up and/or histopathology (when available) was taken as the reference standard. Sensitivity, specificity and predictive values were calculated for PET-CT on both a per-study and per-lesion basis.

RESULTS

The mean patient age was 52.8 ± 11.8 years (male/female: 52/20). Out of 93 PET-CT studies, 56 (60.2%) were positive and 37 (39.8%) were negative for recurrent disease. On per-study-based analysis, 18F-FDG PET-CT has a sensitivity, specificity and accuracy of 95.9, 79.5 and 88.1%, respectively. The accuracy of 18F-FDG PET-CT was 89.2% for local recurrence, 94.6% for lymph nodes, 96.7% for liver, 96.7% for lung, 98.9% for bone and 98.9% for other sites. The accuracy of 18F-FDG PET-CT was lower for local recurrence as compared with that for liver (P=0.012) and bone (P=0.012). No significant difference was found in the diagnostic accuracies for other regions.

CONCLUSION

18F-FDG PET-CT is highly sensitive and specific for detecting recurrence in patients with gastric adenocarcinoma. It shows high accuracy both on a per-patient and per-lesion basis.

Role of ¹⁸F-FDG PET/CT in the prediction of gastric cancer recurrence after curative surgical resection

PURPOSE

The study evaluated the role of preoperative (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT in the prediction of recurrent gastric cancer after curative surgical resection.

METHODS

A total of 271 patients with gastric cancer who underwent (18)F-FDG PET/CT and subsequent curative surgical resection were enrolled. All patients underwent follow-up for cancer recurrence with a mean duration of 24 ± 12 months. (18)F-FDG PET/CT images were visually assessed and, in patients with positive (18)F-FDG cancer uptake, the maximum standardized uptake value (SUV(max)) of cancer lesions was measured. (18)F-FDG PET/CT findings were tested as prognostic factors for cancer recurrence and compared with conventional prognostic factors. Furthermore, (18)F-FDG PET/CT findings were assessed as prognostic factors according to histopathological subtypes.

RESULTS

Of 271 patients, 47 (17 %) had a recurrent event. Positive (18)F-FDG cancer uptake was shown in 149 patients (55 %). Tumour size, depth of invasion, presence of lymph node metastasis, positive (18)F-FDG uptake and SUV(max) were significantly associated with tumour recurrence in univariate analysis, while only depth of invasion, positive (18)F-FDG uptake and SUV(max) had significance in multivariate analysis. The 24-month recurrence-free survival rate was significantly higher in patients with negative (18)F-FDG uptake (95 %) than in those with positive (18)F-FDG uptake (74 %; p < 0.0001). In subgroup analysis, (18)F-FDG uptake was a significant prognostic factor in patients with tubular adenocarcinoma (p = 0.003) or poorly differentiated adenocarcinoma (p = 0.0001). However, only marginal significance was shown in patients with signet-ring cell carcinoma and mucinous carcinoma (p = 0.05).

CONCLUSION

(18)F-FDG uptake of gastric cancer is an independent and significant prognostic factor for tumour recurrence. (18)F-FDG PET/CT could provide effective information on the prognosis after surgical resection of gastric cancer, especially in tubular adenocarcinoma and poorly differentiated adenocarcinoma.

Endoscopy and role of endoscopic resection in gastric cancer

Patient selection for endoscopic resection is based on meticulous endoscopic examination and histological assessment so as to avoid performing this procedure on patients with a high risk of lymph node involvement or metastatic disease. Currently, endoscopic mucosal resection (EMR) is used for tumors <2 cm, and endoscopic submucosal dissection (ESD) should be considered for tumors >2 cm. The advantage of ESD is that it achieves en-bloc resection of larger tumors, potentially reducing the risk of disease recurrence.

Correlation between efficacy of PSK postoperative adjuvant immunochemotherapy for gastric cancer and expression of MHC class I

Protein-bound polysaccharide K (PSK) is a glycoprotein that is purified from the mushroom Coriolus versicolor. In Japan, PSK is clinically used in combination with anticancer agents following gastric cancer surgery. Evaluation of the response is difficult, as efficacy is determined via antitumor immunoenhancing effects, and for that reason PSK has not become a standard therapy. The present study evaluated the expression of MHC class I in gastric cancer patients who received PSK postoperative adjuvant immunochemotherapy, and investigated the correlation between MHC class I expression and clinical outcomes. The subjects comprised 349 patients with stage II/III gastric cancer, who had received adjuvant therapy following curative resection between 1995 and 2008. MHC class I expression in the primary lesion was evaluated by immunohistochemical staining. Patients were divided into two treatment groups: one was only administered oral chemotherapy (chemotherapy-only group) and the other was administered chemotherapy plus PSK (PSK group). The clinical outcomes were compared between the two groups. The two groups did not differ in regard to their MHC class I expression. Expression-negative cases demonstrated 3-year recurrence-free survival (RFS) rates of 65% in the PSK group and 47% in the chemotherapy-only group. Therefore, the PSK group revealed a prolonged survival. For the 82 expression-negative cases with pN2 or greater, the RFS rates were 68% in the PSK group and 28% in the chemotherapy-only group, representing a significant difference. Thus, PSK adjuvant immunochemotherapy may be effective in MHC class I-negative patients, who are in a state of antitumor immunological tolerance, and patients with advanced lymph node metastasis of pN2 or greater.

Topical application of acetic acid in cytoreduction of gastric cancer. A technical report using mouse model

BACKGROUND AND AIM

Application of acetic acid topically to the mucosal or serosal side of the stomach has been well used to create a chronic gastric ulcer model. The aim of the present study was to apply it as a new cytoreductive approach in a mouse model of gastric cancer.

METHODS

A total of 43 genetically engineered mice, the so-called (INS-GAS) mice that develop spontaneously gastric cancer at 10-14 months of age, were included. Acetic acid-induced ulcer method was applied to mice under isofluran anesthesia. The ulcer at the cancer side was made by exposing either the anterior serosal or posterior mucosal side of gastric wall to 0.1 mL of 60% or 100% acetic acid for 30 or 60 s with a cylindrical metal mold (4 mm ID). Route to the serosal side was intra-abdominal and one to the mucosal side was through a small hole made in the forestomach. The opposite side of gastric wall (no treatment with acetic acid) was used as the corresponding control. After the mice were sacrificed, the stomachs were collected 1, 3, 6 h or 1, 3 and 7 days, postoperatively, and evaluated by visual inspection and histology.

RESULTS

Gastric cancer was found in both the anterior and posterior walls of the corpus in all 43 mice. Intraluminal pH value was between 11 and 13. Severe necrosis in the cancer was observed in the side exposing to acetic acid, but not in the control side, shortly after the treatment (i.e. within 30 or 60 min). The muscularis mucosa and muscle layers were less damaged, regardless of the side of the treatment. Ulcer formation in the cancer took place 1, 3 or 7 days later. The ulcer depth was sometimes at the muscularis mucosa and muscle layers. At 3 and 7 days, regeneration of epithelial cells was clearly observed in the ulcer margin in the stomach of mice.

CONCLUSIONS

Topical application of acetic acid either from mucosal or serosal surface promptly caused the necrosis of tumor, suggesting the potential approach of this simple and reliable method as a cytoreductive treatment of gastric cancer in patients through endoscopy or laparoscopy.

Role of fluoro-2-deoxyglucose positron emission tomography for the detection of gastrointestinal tract lesions in patients with lung cancer

BACKGROUND

  The purpose of this study was to clarify the clinical characteristics of lung cancer patients with abnormal accumulation of fluoro-2-deoxyglucose (FDG) in the gastrointestinal tract imaged by positron emission tomography (PET).

METHODS

  Of 1071 consecutive patients with primary lung cancer who underwent PET from October 2005 through to March 2010, 25 patients (2.3%) showed localized abnormal FDG accumulation in the gastrointestinal tract. We retrospectively compared the location of abnormal accumulation in the gastrointestinal tract, the maximum standardized uptake value in 1 hour, and final clinical diagnosis.

RESULTS

  Of the 25 cases, 12 (48%) were true PET-positive cases (esophageal cancer in one case, gastric cancer in one, colorectal cancer in seven, gastrointestinal stromal tumor in one, and lung cancer metastasis to the stomach and small intestine in one patient each). The 13 cases with false PET-positives were gastric polyp in one, gastritis in four, colon polyp in two, diverticulitis in one, and normal physiological accumulation in five. There was also a significant difference between malignancy and benign intestinal accumulation excluding the stomach (P = 0.002).

CONCLUSION

  PET was useful for screening the gastrointestinal tract (except the stomach) for malignancy in lung cancer patients.

Latest developments and emerging treatment options in the management of stomach cancer

Gastric cancer remains a significant health burden worldwide. Most of these malignancies are diagnosed at an advanced stage and are associated with a grim prognosis. Complete removal of macroscopic and microscopic tumor masses along with regional lymphnodes (R0 surgical resection) represents the treatment of choice in localized, nonmetastatic gastric cancer. Chemotherapy, either alone as a perioperative treatment, or in combination with radiation therapy in an adjuvant setting, improves the clinical outcome for patients with resectable tumors. In patients suffering from metastatic disease, chemotherapy and the so-called targeted therapies play a major role in improving survival and quality of life compared with best supportive care. The emergence of new drugs as well as new administration schedules allow physicians to obtain an objective response of up to 60% and, since the utilization of targeted therapies, overall survival has reached 14 months. In order to situate the standard of care and the latest developments in gastric malignancies better, the pertinent English literature, including major Phase III randomized studies and meta-analyses, has been reviewed.