The role of PET/CT in detection of gastric cancer recurrence. BMC Cancer. 2009;9:73. [PMID: 19250554 PMCID: PMC2651906 DOI: 10.1186/1471-2407-9-73]

Management strategies for locoregional recurrence in early-stage gastric cancer: retrospective analysis and comprehensive literature review

OBJECTIVE

To present a comprehensive account and literature review addressing the anatomical distribution, natural history, and management strategies for locoregional recurrence in early-stage gastric cancer (EGC).

PATIENTS AND METHODS

Retrospective chart review of patients presenting with EGC recurrence at King Hussein Cancer Center (Amman, Jordan) between July 2006 and May 2009. A literature review of publications addressing recurrence following surgery for EGC was undertaken via a systematic search of PUBMED database and National Comprehensive Cancer Network (NCCN) guideline updates.

RESULTS

Seventeen patients presented with EGC, three of whom (17.6%) were pathologically staged as T2N1 [1/33 lymph nodes (LNs)], T1N0, and T1N0 were afflicted by recurrence following R0 partial gastrectomy. Literature review yielded 18 studies specifically addressing recurrence in EGC. Several management strategies have been proposed for isolated recurrence following gastrectomy in EGC. NCCN clinical practice guideline updates do not take into consideration whether the recurrence is isolated or widespread and whether the initial stage is early or advanced.

CONCLUSIONS

While acknowledging the limitations of this study, including the small sample size and the short follow-up period, it appears clear that oncologic treatment is possible for EGC recurrence, particularly, in patients with isolated relapse. Guideline updates should differentiate between management strategies suitable for recurrence occurring in early versus advanced initial cancer stage.

Clinical significance of lymph node micrometastasis in gastric cancer

Recently, the existence of lymph node micrometastasis (LNM), including isolated tumor cells, has been focused on during the development of molecular diagnostic tools for lymph node metastasis in various malignant neoplasms. In particular, immunohistochemistry and reverse transcription-polymerase chain reaction have been reported to be available for the detection of LNM in gastric cancer. However, at present, the clinical significance of LNM remains unclear in patients with gastric cancer. Therefore, we cannot strategically make light of this issue in clinical management. Currently, minimally invasive treatments, such as endoscopic submucosal dissection and laparoscopic surgery with personalized lymphadenectomy, are widely performed in consideration of postsurgical quality of life (QOL). However, it is important to maintain the balance between QOL and curability when selecting surgical treatments for patients with gastric cancer. If minimally invasive surgery based on LNM status was established for patients with early gastric cancer, it could be performed safely. We reviewed the clinical significance of LNM as an important strategic target in patients with gastric cancer.

18 F-fluorodeoxyglucose positron emission tomography to evaluate recurrent gastric cancer: a systematic review and meta-analysis

BACKGROUND AND AIM

We aimed to explore the role of the diagnostic accuracy of (18) F-fluorodeoxyglucose positron emission tomography ((18) F-FDG PET) in detecting recurrent gastric cancer through a systematic review and meta-analysis.

METHODS

The MEDLINE, EMBASE, Cancerlit, and Cochrane Library database, from January 2001 to July 2011, were searched for studies evaluating the diagnostic performance of (18) F-FDG PET in detecting recurrent gastric cancer. We determined the sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR-), and constructed summary receiver operating characteristic curves. We also compared the performance of (18) F-FDG PET with computed tomography (CT) by analyzing studies that had also used these diagnostic methods on the same patients.

RESULTS

Across nine studies (526 patients), the overall sensitivity of (18) F-FDG PET was 0.78 (95% confidence interval [CI]: 0.68-0.86), and the overall specificity was 0.82 (95% CI: 0.76-0.87). Overall, LR+ was 3.52 (95% CI: 2.68-4.63) and LR- was 0.32 (95% CI: 0.22-0.46). In studies in which both (18) F-FDG PET and other diagnostic tests were performed, the sensitivity and specificity of (18) F-FDG PET were 0.72 (95% CI: 0.62-0.80) and 0.84 (95% CI: 0.77-0.90), respectively; of contrast CT, they were 0.74 (95% CI: 0.64-0.83) and 0.85 (95% CI: 0.78-0.90), respectively; and of combined PET and CT, they were 0.75 (95% CI: 0.67-0.82) and 0.85 (95% CI 0.79-0.90), respectively. Study sensitivity was not correlated with the prevalence of recurrent gastric cancer.

CONCLUSION

(18) F-FDG PET has good diagnostic performance in the overall evaluation of recurrent gastric cancer, but still has some limited performance compared with contrast CT. (18) F-FDG PET combined with CT might improve the diagnostic performance in detecting recurrent gastric cancer.

Clinical significance of the B7-H4 coregulatory molecule as a novel prognostic marker in gastric cancer

BACKGROUND

The B7-H4 coregulatory molecule is a member of the B7 family of molecules, which regulate the T-cell-mediated immune response through CD28 receptors. Recently, B7-H4 has been reported to be a negative regulator of the immune response in patients with several malignant diseases. However, few reports have investigated the clinical significance of B7-H4 expression in patients with gastric cancer. In the present study, we analyzed B7-H4 expression and the relationship between its expression and clinicopathological factors including prognosis in gastric cancer.

METHODS

B7-H4 expression in gastric cancer cell lines and clinical gastric cancer specimens was initially assessed with the reverse transcription-polymerase chain reaction (RT-PCR). Moreover, B7-H4 and CD3 expression in 120 resected specimens from gastric cancer patients were evaluated by immunohistochemistry (IHC).

RESULTS

B7-H4 expression was identified in the gastric cancer cell lines and clinical tumor tissues by RT-PCR. B7-H4 expression was high in 25.8% (31/120) of resected tumor specimens. B7-H4 expression significantly correlated with tumor stage (P = 0.04). The 5-year survival rate was significantly lower in patients with high B7-H4 expression than in those with low B7-H4 expression (P = 0.001). Multivariate analysis demonstrated that B7-H4 expression was an independent prognostic factor (P = 0.035). Immunohistochemical analysis of CD3 expression showed that B7-H4 expression was inversely correlated with the number of tumor infiltrating T lymphocytes (P < 0.001).

CONCLUSIONS

The B7-H4 coregulatory molecule is a novel prognostic marker related to the T-cell-mediated immune response, and its pathway may be a molecular target for controlling tumor progression in patients with gastric cancer.

Role of (18F) 2-fluoro-2-deoxyglucose positron emission tomography in upper gastrointestinal malignancies

The role of whole-body FDG [(¹⁸F) 2-fluoro-2-deoxyglucose] positron emission tomography (PET) scanning as an imaging modality in the management of patients with malignancy has evolved enormously over the past two decades. FDG-PET has demonstrated significant efficacy in the staging, prognostication and detection of occult metastatic disease in malignancies of the gastrointestinal tract, in addition to assessment of the response to cytotoxic chemotherapy in a more timely manner than has traditionally been possible by more conventional imaging tools. The sensitivity and specificity of FDG-PET for the detection and staging of malignancy depend not only on the site and size of the primary tumor and metastases, but also on histological cell type, reflecting underlying disparities in glucose metabolism. The metabolic response to neo-adjuvant chemotherapy or to chemo-radiotherapy in cancers of the gastro-esophageal junction or stomach has been demonstrated in several prospective studies to correlate significantly with both the histological tumor response to treatment and with consequent improvements in overall survival. This may offer a future paradigm of personalized treatment based on the PET response to chemotherapy. FDG-PET has been less successful in efforts to screen for and detect recurrent upper gastrointestinal malignancies, and in the detection of low volume metastatic peritoneal disease. Efforts to improve the accuracy of PET include the use of novel radiotracers such as (¹⁸F) FLT (3-deoxy-3-fluorothymidine) or ¹¹C-choline, or fusion PET-CT with concurrent high-resolution computed tomography. This review focuses on the role of FDG-PET scanning in staging and response assessment in malignancies of the upper gastrointestinal tract, specifically gastric, esophageal and pancreas carcinoma.

Significance of SUV on Follow-up F-18 FDG PET at the Anastomotic Site of Gastroduodenostomy after Distal Subtotal Gastrectomy in Patients with Gastric Cancer

PURPOSE

The aim of this study was to characterize the patterns of fluorodeoxyglucose (FDG) uptake on F-18 FDG positron emission tomography/computed tomography (FDG PET/CT) at the anastomotic site of gastroduodenostomy after distal subtotal gastrectomy in patients with gastric cancer.

METHODS

From May 2007 to May 2010, two or more follow-up measurements using FDG PET/CT scans were done for 19 patients (11 men, 8 women; mean age, 62.0 ± 10.3 years) who underwent distal subtotal gastrectomy with gastroduodenostomy between February 2006 and March 2008 for detecting gastric cancer recurrence at our medical center. The FDG PET/CT images were retrospectively reviewed. Patients with local recurrence, regional nodal metastasis or distant metastasis on follow-up studies were excluded. CT and endoscopy were done within 1 month before or after the FDG PET/CT scan. Eight patients had two follow-ups of FDG PET/CT, and 11 patients had three follow-ups. The mean interval between surgery and the first follow-up FDG PET/CT was 12.9 ± 0.8 months (n = 19); between the first and second it was 12.3 ± 1.0 months (n = 19); between the second and third it was 11.6 ± 0.7 months (n = 11). The F-18 FDG uptakes at the anastomotic site and fundus in the remnant stomach were measured by maximum standardized uptake value (SUVmax) using a region of interest technique.

RESULTS

The SUVmax at the anastomotic site was significantly higher than that of the fundus on all series of first, second and third follow-up studies (3.3 ± 1.1 vs. 2.1 ± 0.7, p < 0.001: 3.1 ± 0.9 vs. 2.2 ± 0.7, p = 0.001: 3.0 ± 0.6 vs. 2.1 ± 0.7, p = 0.006, respectively). The SUVmax for the anastomotic site and fundus, and SUVmax ratio for the anastomotic site over the fundus were not significantly different throughout the series.

CONCLUSION

The SUVmax at the anastomotic site is significantly higher than that of the fundus and does not decrease significantly over time. Therefore, the local recurrence of gastric cancer after surgery could not be definitely differentiated from physiologic uptake or postoperative inflammatory change.

F18-fluorodeoxyglucose-positron emission tomography and computed tomography is not accurate in preoperative staging of gastric cancer

PURPOSE

To investigate the clinical benefits of F18-fluorodeoxyglucose-positron emission tomography and computed tomography ((18)F-FDG-PET/CT) over multi-detector row CT (MDCT) in preoperative staging of gastric cancer.

METHODS

FDG-PET/CT and MDCT were performed on 78 patients with gastric cancer pathologically diagnosed by endoscopy. The accuracy of radiologic staging retrospectively was compared to pathologic result after curative resection.

RESULTS

Primary tumors were detected in 51 (65.4%) patients with (18)F-FDG-PET/CT, and 47 (60.3%) patients with MDCT. Regarding detection of lymph node metastasis, the sensitivity of FDG-PET/CT was 51.5% with an accuracy of 71.8%, whereas those of MDCT were 69.7% and 69.2%, respectively. The sensitivity of (18)F-FDG-PET/CT for a primary tumor with signet ring cell carcinoma was lower than that of (18)F-FDG-PET/CT for a primary tumor with non-signet ring cell carcinoma (35.3% vs. 73.8%, P < 0.01).

CONCLUSION

Due to its low sensitivity, (18)F-FDG-PET/CT alone shows no definite clinical benefit for prediction of lymph node metastasis in preoperative staging of gastric cancer.

Detecting the recurrence of gastric cancer after curative resection: comparison of FDG PET/CT and contrast-enhanced abdominal CT

The purpose of this study was to evaluate the value of fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) for detecting the recurrence of gastric cancer. We performed a retrospective review of 139 consecutive patients who underwent PET/CT and contrast-enhanced abdominal CT (CECT) for surveillance of gastric cancer after curative resection. Recurrence of gastric cancer was validated by histopathologic examination for local recurrence or serial imaging study follow-up with at least 1 yr interval for recurrence of distant metastasis form. Twenty-eight patients (20.1%) were confirmed as recurrence. On the patient based analysis, there was no statistically significant difference in the sensitivity, specificity and accuracy of PET/CT (53.6%, 84.7%, and 78.4%, respectively) and those of CECT (64.3%, 86.5%, and 82.0%, respectively) for detecting tumor recurrence except in detection of peritoneal carcinomatosis. Among 36 recurrent lesions, 8 lesions (22.2%) were detected only on PET/CT, and 10 lesions (27.8%) only on CECT. PET/CT had detected secondary malignancy in 8 patients. PET/CT is as accurate as CECT in detection of gastric cancer recurrence after curative resection, excepting detection of peritoneal carcinomatosis. Moreover, additional PET/CT on CECT could improve detection rate of tumor recurrence and provide other critical information such as unexpected secondary malignancy.

Clinical implication of FDG-PET in advanced gastric cancer with signet ring cell histology

BACKGROUND AND OBJECTIVES

The purpose of this study was to investigate the role of the standardized uptake values (SUV), a semi-quantitative assessment of tumor FDG uptake, as a prognosticator for advanced signet ring cell carcinoma (SRC).

METHODS

We reviewed the files of 41 patients who underwent curative gastrectomy for advanced SRC and who had an FDG-PET at initial presentation between September 2003 and December 2007.

RESULTS

The median follow-up period was 30.9 months (range: 4.0-70.3). We found a correlation between the SUVmax and TNM stage. When the patients were divided into two groups (low vs. high SUVmax) based on a median SUVmax of 3.80, the high-SUVmax group showed more aggressive tumor behavior than did the low SUVmax group. In addition, the high SUVmax group showed more postoperative recurrence (P = 0.028), shorter relapse-free survival (P = 0.004), and lower 30-month cancer-specific survival rates (40.0% vs. 69.3%, P = 0.008). However, in multivariate analysis, SUVmax failed to be an independent predictor of overall survival.

CONCLUSIONS

Although SUVmax of initial PET scan was not an independent predictor of patient outcomes after curative surgery, higher SUVmax is associated with more advanced stage and indicates more aggressive tumor biology in advanced SRC.

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

Since April 2010, the Japanese Public Health Insurance System has covered the costs incurred for performing ¹⁸F-fluoro-2-deoxyglucose positron emission tomography (FDG-PET) imaging for patients with advanced gastric cancer. The aim of this review was to evaluate the clinical impact of PET for patients with gastric cancer. A systematic literature search was performed in PubMed/MEDLINE using the keywords "gastric cancer" and "PET" to search for relevant articles published from January 2000 to September 2010. The clinical impact of selected articles was assessed by the authors to evaluate the following: (a) tumor staging, (b) diagnosis for recurrent disease, (c) evaluation of treatment response, and (d) screening for gastric cancer. FDG uptake increases in papillary adenocarcinoma, tubular adenocarcinoma, and solid-type poorly differentiated adenocarcinoma. This uptake is also associated with glucose transporter 1 expression. The sensitivity and specificity of FDG-PET for metastatic lymph node detection were 21-40% and 89-100%, respectively. The sensitivity and specificity for distant metastasis detection were 35-74% and 74-99%, respectively. Treatment response can be detectable at an earlier stage by PET than by computed tomography (CT), because FDG uptake by cancer cells decreases according to the treatment response. In summary, although PET has limitations such as frequent false-negative cases in signet-ring cell carcinoma and non-solid type poorly differentiated carcinoma, it can contribute to the selection of a more appropriate treatment modality by detecting distant metastases and treatment response.

Combination of hsa-miR-375 and hsa-miR-142-5p as a predictor for recurrence risk in gastric cancer patients following surgical resection

BACKGROUND

Recurrence is a major factor leading to treatment failure and death in gastric cancer (GC) patients following surgical resection. Importantly, the prediction of recurrence is critical in improving clinical outcomes. We isolated a group of microRNAs (miRNAs) and evaluated their usefulness as prognostic markers for the recurrence of GC.

PATIENTS AND METHODS

A total of 65 GC patients were selected for systematic analysis, 29 patients with recurrence and 36 patients without recurrence. Firstly, miRNAs microarray and bioinformatics methods were used to characterize classifiers from primary tumor samples (n = 8). Following, we validated these predictors both in frozen fresh and paraffin-embedded tissue samples (n = 57) using quantitative PCR.

RESULTS

We have identified 17 differential miRNAs including 10 up-regulated and 7 down-regulated miRNAs in recurrence group. Using k-top scoring pairs (k-TSP) method, we further ascertained hsa-miR-375 and hsa-miR-142-5p as a classifier to recognize recurrence and nonrecurrence cases both in the training and test samples. Moreover, we validated this classifier in 34 frozen fresh tissues and 38 paraffin-embedded tissues with consistent sensitivity and specificity with training set; among them, 15 cases were matched. A high frequency recurrence and poor survival were observed in GC cases with high level of hsa-miR-375 and low level of hsa-miR-142-5p (P < 0.001). In addition, we evaluated that hsa-miR-375 and hsa-miR-142-5p were involved in regulating target genes in several oncogenic signal pathways, such as TP53, MAPK, Wnt and vascular endothelial growth factor.

CONCLUSION

Our results indicate that the combination of hsa-miR-375 and hsa-miR-142-5p as a predictor of disease progression has the potential to predict recurrence risk for GC patients.

The role of 18F-FDG PET/CT in the evaluation of gastric cancer recurrence after curative gastrectomy

PURPOSE

(18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) scans are frequently performed for the screening or staging of malignant tumors. This study aimed to assess the usefulness of (18)F-FDG PET/CT in detection of gastric cancer recurrence after curative gastrectomy.

MATERIALS AND METHODS

Eighty nine patients who had undergone curative gastrectomy due to gastric cancer and had (18)F-FDG PET/CT and contrast CT scans within 2 weeks for surveillance in asymptomatic patients (n = 11) or to clarify suspected recurrence (n = 78) were consecutively collected and retrospectively analyzed. They had clinical follow-up for at least 12 months after PET/CT and CT scans.

RESULTS

Fifteen of the 89 patients (16.9%) were diagnosed with recurrent gastric cancer in 21 organs. Forty one organs showed an increase in FDG uptake, and only 9 of these organs were diagnosed with recurrent gastric cancer by (18)F-FDG PET/CT. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of the (18)F-FDG PET/CT were 42.9%, 59.7%, 29.3%, 78.2%, and 57.3%, respectively. On the CT scan, 18 of 21 recurrent gastric cancers were detected, and 7 cases were in agreement with the (18)F-FDG PET/CT. The sensitivity and specificity of the CT scan were 85.8% and 87.3%, respectively, which are superior to the (18)F-FDG PET/CT. When we diagnosed a recurrence based on either (18)F-FDG PET/CT or CT scans, the sensitivity increased to 95.2% and the specificity decreased to 45.6%, when compared with the contrast CT scan alone.

CONCLUSION

(18)F-FDG PET/CT is an insufficient diagnostic method in detection of recurrence after curative gastrectomy, and even less accurate than contrast CT scan alone.

The role of ¹⁸F-FDG PET/CT in the assessment of suspected recurrent gastric cancer after initial surgical resection: can the results of FDG PET/CT influence patients' treatment decision making?

PURPOSE

(18)F-fluorodeoxyglucose (FDG) PET/CT has been widely used for staging, re-staging and for monitoring therapy-induced changes and response to therapy in patients with various types of cancer, but its utilization for gastric cancer has been limited. The purpose of this study was to evaluate the clinical role of FDG PET/CT in the detection of gastric cancer recurrence as compared with diagnostic CT and to assess the impact of FDG PET/CT results on patients' treatment planning.

METHODS

Thirty-four patients with suspected recurrent gastric cancer, who had previously undergone curative gastrectomy and lymph node dissection, were retrospectively analysed. The diagnostic CT and FDG PET/CT imaging were performed for all patients as clinically indicated. The results of FDG PET/CT were compared with the findings of the diagnostic CT. The changes in the clinical management of patients according to the results of FDG PET/CT were also evaluated.

RESULTS

FDG PET/CT was performed in 19 patients (55.9%) due to the suspicion of distant metastasis at diagnostic CT. The remaining 15 patients were suspected to have local recurrence at diagnostic CT (n = 4) or gastroscopy (n = 1) and due to an increase in tumour markers or clinical manifestations (n = 10). The FDG PET/CT result was positive in 23 patients (67.6%) and negative in 11 patients (32.4%). In total, 24 (70.6%) of the 34 patients had documented recurrent disease by histopathology in 7 (29.1%) and by clinical follow-up in 17 (70.9%), while 11 patients had no evidence of recurrent disease. FDG PET/CT correctly confirmed recurrent disease in 23 of the patients with recurrence and it was classified as true-positive in these patients. However, FDG PET/CT was false-negative in one patient but recurrent disease was confirmed by histopathology. The overall sensitivity, specificity, accuracy, positive and negative predictive values of FDG PET/CT were significantly superior to those of diagnostic CT (95.8 vs 62.5%, 100 vs 10%, 97 vs 47%, 100 vs 62.5% and 90.9 vs 10%, respectively, p = 0.012) in the detection of recurrent gastric cancer after initial surgery. The FDG PET/CT results changed the patients' management in 18 (52.9%) cases by leading to the use of previously unplanned treatment procedures in 9 (50%) patients and the avoidance of previously planned therapeutic procedures in 9 (50%) patients.

CONCLUSION

FDG PET/CT is a superior post-therapy surveillance modality for the diagnosis of recurrent gastric cancer compared with diagnostic CT imaging after initial surgery. In addition, integrated FDG PET/CT was specifically helpful in optimizing the treatment plan and it might play an important role in treatment stratification in the future.

Benefit of post-operative surveillance for recurrence after curative resection for gastric cancer

BACKGROUND

Although most clinicians perform surveillance after gastrectomy, there is no consensus on the optimal follow-up schedule. This study aimed to evaluate the benefit of postoperative surveillance for recurrence after curative resection for gastric cancer.

METHOD

We retrospectively studied 110 patients who had recurrences after undergoing curative gastrectomies between 2000 and 2004 at Korea University Hospital. We analyzed the clinico-pathologic factors and oncologic results according to the presence of recurrence symptoms.

RESULTS

Fifty-five (50%) patients had symptomatic recurrences. There were significant differences in recurrence patterns; locoregional (29.1%) and peritoneal recurrences (27.3%) were dominant in asymptomatic group; peritoneal (47.3%) and hematogenous recurrences (25.5%) were dominant in symptomatic group. The median recurrence-free survival was not different for both groups (p = 0.054). However, median overall and post-recurrence survival was poor in the symptomatic group (p = 0.004, p < 0.001). The presence of symptoms and short disease-free survival were independent poor prognostic factors for post-recurrence survival.

CONCLUSION

Patients with asymptomatic recurrences could have increased survival compared to symptomatic patients. Although our post-operative surveillance could not be any benefit to improve outcomes for recurrent gastric cancer, it is important to discriminate the nature of recurrent gastric cancer by the presence of symptoms for planning further treatment.

Feasibility of using 18F-FDG PET/CT for pretherapeutic evaluation of advanced gastric cancer

AIM: To investigate the feasibility of using ¹⁸F-FDG PET/CT for pretherapeutic evaluation of advanced gastric cancer.

METHODS: The clinical records of 40 advanced gastric cancer patients who underwent ¹⁸F-FDG PET/CT before treatment were reviewed retrospectively. Of these patients, 14 patients underwent radical gastrectomy, and the other patients underwent chemotherapy or palliative gastrectomy. The lymph nodes were classified into two groups (N₁ + N₂ group and N₃ group) based on anatomic sites. Lymph node metastasis was assessed on group basis. All PET/CT images were interpreted according to visual evaluation and standardized uptake values (SUVs).

RESULTS: The diagnostic sensitivity of ¹⁸F-FDG PET/CT, PET and CT for primary tumors was 97.5%, 65% and 90%, respectively. The sensitivity, specificity, and accuracy of 18F-FDG PET/CT for N₁ + N₂ metastases were 71.4%, 77.8% and 85.7%, respectively, while the sensitivity of PET/CT for N₃ metastases was 100%. PET/CT detected 21 cases of metastases undetected by routine method. Accordingly, the TNM stage of tumors was upgraded in 40% of patients.

CONCLUSION: It is feasible to use ¹⁸F-FDG PET/CT for pretherapeutic evaluation of advanced gastric cancer, and the diagnostic outcomes revealed by PET/CT may have a clinically significant impact on the choice of initial therapy.