Clinical significance of CT-defined minimal ascites in patients with gastric cancer

Clinical implications of CT-detected ascites in gastric cancer: association with peritoneal metastasis and systemic inflammatory response

OBJECTIVES

This study aimed to evaluate the diagnostic significance of computed tomography (CT) detected ascites in gastric cancer (GC) with peritoneal metastasis (PM) and investigate its association with systemic inflammatory response.

METHODS

This retrospective study included 111 GCs with ascites (PM: n = 51; No PM: n = 60). Systemic inflammatory indexes, tumor markers, and the CT-assessed characteristics of ascites were collected. The differences in parameters between the two groups were analyzed. Diagnostic performance was obtained by receiver operating characteristic curve analysis. The association between the volume of ascites and clinical characteristics was evaluated with correlation analysis.

RESULTS

In this study, over half of GCs with ascites were not involved with PM. The systemic immune-inflammation index (SII), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), five tumor markers, and the characteristics of ascites showed significant differences between the two groups (all p < 0.05). Among them, SII, NLR, PLR, and the volume of ascites achieved the areas under the curve of 0.700, 0.698, 0.704, and 0.903, respectively. Moreover, the volumes of ascites showed positive correlations with SII, NLR, and PLR in GCs with PM, and the volumes of ascites detected in the upper abdomen were more strongly correlated with CA125 level (all p < 0.05).

CONCLUSION

Many GCs with CT-detected ascites did not occur with synchronous PM. The presence of upper abdominal ascites had certain clinical significance for diagnosing PM in GCs. Systemic inflammatory indexes were elevated and positively correlated with the volume of ascites in GCs with PM, which might suggest the enhanced systemic inflammatory response.

CRITICAL RELEVANCE STATEMENT

CT-detected ascites in the upper abdomen played an indicative role in identifying synchronous PM in GCs, and the systemic inflammatory response was enhanced in GCs with PM, which might be helpful for clinical evaluation.

KEY POINTS

Many GCs with CT-detected ascites did not occur with synchronous PM. CT-detected ascites in the upper abdomen help in identifying PM in GCs. GCs with PM showed elevated systemic inflammatory indexes and enhanced systemic inflammatory response.

Prognostic Impact of Minimal Pelvic Fluid in Locally Advanced Pancreatic Cancer: A Multicenter Retrospective Study

BACKGROUND/AIMS

Minimal pelvic fluid (MPF) is occasionally encountered on computed tomography (CT) scans during the initial staging of newly diagnosed pancreatic cancer. However, its clinical relevance has scarcely been studied. This study intends to explore the incidence of minimal pelvic fluid and its relevance in terms of survival in locally advanced pancreatic cancer (LAPC) patients.

MATERIALS AND METHODS

The medical records of patients with LAPC at 4 tertiary referral institutions were retrospectively reviewed from January 2005 to December 2015. Minimal pelvic fluid was defined as a fluid collection volume in the pelvic cavity of <100 mL as determined by abdominal CT. The association between the presence of MPF and patient survival was evaluated.

RESULTS

A total of 59 patients (male:female, 33:26; median age, 68 years; range 46-82 years) with LAPC were enrolled. Of the 59 patients, 22.0% (n = 13) had MPF, and 78.0% (n = 46) had no pelvic fluid (NPF). Baseline clinical characteristics in the 2 groups, including extent of the tumor stage, extent of spread to the lymph nodes stage, and pattern of treatments, were not significantly different. However, median overall survival was significantly less in the MPF group [9.7 months, (95% CI, 5.9-13.5)] than in the NPF group as determined by the log-rank test [16.9 months, (95% CI, 9.3-24.5)] (P = .002), and univariate and multivariate analyses showed that the presence of MPF independently predicted a poor prognosis.

CONCLUSION

The presence of MPF was found to be significantly associated with reduced survival and an independent poor prognostic biomarker in LAPC patients.

Unravelling Peritoneal Carcinomatosis Using Cross-Sectional Imaging Modalities

Peritoneal carcinomatosis (PC) refers to malignant epithelial cells that spread to the peritoneum, principally from abdominal malignancies. Until recently, PC prognosis has been considered ill-fated, with palliative therapies serving as the only treatment option. New locoregional treatments are changing the outcome of PC, and imaging modalities have a critical role in early diagnosis and disease staging, determining treatment decision making strategies. The aim of this review is to provide a practical approach for detecting and characterizing peritoneal deposits in cross-sectional imaging modalities, taking into account their appearances, including the secondary complications, the anatomical characteristics of the peritoneal cavity, together with the differential diagnosis with other benign and malignant peritoneal conditions. Among the cross-sectional imaging modalities, computed tomography (CT) is widely available and fast; however, magnetic resonance (MR) performs better in terms of sensitivity (92% vs. 68%), due to its higher contrast resolution. The appearance of peritoneal deposits on CT and MR mainly depends on the primary tumour histology; in case of unknown primary tumour (3-5% of cases), their behaviour at imaging may provide insights into the tumour origin. The timepoint of tumour evolution, previous or ongoing treatments, and the peritoneal spaces in which they occur also play an important role in determining the appearance of peritoneal deposits. Thus, knowledge of peritoneal anatomy and fluid circulation is essential in the detection and characterisation of peritoneal deposits. Several benign and malignant conditions show similar imaging features that overlap those of PC, making differential diagnosis challenging. Knowledge of peritoneal anatomy and primary tumour histology is crucial, but one must also consider clinical history, laboratory findings, and previous imaging examinations to achieve a correct diagnosis. In conclusion, to correctly diagnose PC in cross-sectional imaging modalities, knowledge of peritoneal anatomy and peritoneal fluid flow characteristics are mandatory. Peritoneal deposit features reflect the primary tumour characteristics, and this specificity may be helpful in its identification when it is unknown. Moreover, several benign and malignant peritoneal conditions may mimic PC, which need to be considered even in oncologic patients.

Primary and secondary tumors of the peritoneum: key imaging features and differential diagnosis with surgical and pathological correlation

Peritoneal malignancies represent a diagnostic challenge for abdominal radiologists, oncologists, surgeons and pathologists in multidisciplinary teams, who must address their differential diagnosis, staging and treatment. In this article, we explain the pathophysiology of these processes and lay out the role of different imaging techniques in their evaluation. Then, we review the clinical and epidemiological aspects, the main radiological features and the therapeutic approaches for each primary and secondary peritoneal neoplasm, with surgical and pathological correlation. We further describe other rare peritoneal tumors of uncertain origin and a variety of entities that may mimic peritoneal malignancy. Finally, we summarize the key imaging findings of each peritoneal neoplasm to facilitate an accurate differential diagnosis that may impact patient management.Clinical relevance statementImaging plays an essential role in the evaluation of peritoneal malignancies, assessing their extension, detecting unfavorable sites of involvement and facilitating an accurate differential diagnosis, helping to choose the best therapeutic approach.

Peritoneal malignancy: anatomy, pathophysiology and an update on modern day imaging

With increasing subspecialised experience in radical cytoreductive surgery and intra-abdominal chemotherapy for peritoneal malignancy, outcomes have improved significantly in selected patients. The surgery and the treatment regimens are radical and therefore correct patient selection is critical. The radiologist plays a central role in this process by estimating, as precisely as possible, the pre-treatment disease burden. Because of the nature of the disease process, accurate staging is not an easy task. Tumour deposits may be very small and in locations where they are very difficult to detect. It must be acknowledged that no form of modern day imaging has the capability of detecting the smallest peritoneal nodules, which may only be visible to direct inspection or histopathological evaluation. Nonetheless, it behoves the radiologist to be as exact and precise as possible in the reporting of this disease process. This is both to select patients who are likely to benefit from radical treatment, and just as importantly, to identify patients who are unlikely to achieve adequate cytoreductive outcomes. In this review, we outline the patterns of spread of disease and the anatomic basis for this, as well as the essential aspects of reporting abdominal studies in this patient group. We provide an evidence-based update on the relative strengths and limitations of our available multimodality imaging techniques namely CT, MRI and positron emission tomography/CT.

Comparison of clinical-computed tomography model with 2D and 3D radiomics models to predict occult peritoneal metastases in advanced gastric cancer

PURPOSE

To compare the ability of a clinical-computed tomography (CT) model vs. 2D and 3D radiomics models for predicting occult peritoneal metastasis (PM) in patients with advanced gastric cancer (AGC).

METHODS

In this retrospective study, we included 49 patients with occult PM and 49 control patients (without PM) who underwent preoperative CT and subsequent surgery between January 2016 and December 2018. Clinical information and CT semantic features were collected, and CT radiomics features were extracted. A predictive clinical-CT model was created using multivariate logistic regression. The least absolute shrinkage and selection operator algorithm and logistic regression were used for constructing 2D and 3D radiomics models. These models were validated with an external cohort (n = 30). Receiver operating characteristics curve with area under the curve (AUC), sensitivity, and specificity were used to evaluate predictive performance.

RESULTS

Tumor size, mild ascites, and serum CA125 were independent factors predictive of occult PM. The clinical-CT model of these independent factors showed better diagnostic performance than 2D and 3D radiomics models. In the external validation cohort, the AUCs of different models were as follows-clinical-CT model: 0.853 (sensitivity, 66.7%; specificity, 93.3%); 2D radiomics model: 0.622 (sensitivity, 80.0%; specificity, 46.7%); and 3D radiomics model: 0.676 (sensitivity, 60.0%; specificity, 86.0%). The clinical-CT model nomogram showed good clinical predictive efficiency to assess occult PM.

CONCLUSION

The clinical-CT model was better than the radiomics models in predicting occult PM in AGC.

Prevalence and Clinical Implications of Ascites in Gastric Cancer Patients after Curative Surgery

We aimed to determine the frequency and clinical significance of ascites that developed during the follow-up period in patients who underwent curative resection for gastric cancer. The study included 577 patients with gastric cancer who underwent curative gastrectomy. Among them, 184 showed ascites in postoperative follow-up images. Benign ascites was observed in 131 of 490 patients without recurrence, 48 patients (of 87) with recurrence had malignancy-related ascites, and the remaining 5 patients had ascites only prior to recurrence. In most patients without recurrence (97.7%) and in 50% of patients with malignancy-related ascites, the ascites was small in volume and located in the pelvic cavity at the time that it was first identified. However, with the exception of nine patients, malignancy-related pelvic ascites occurred simultaneously or after obvious recurrence. Of those nine patients who had minimal pelvic ascites before obvious recurrence, only one had a clear association with a malignancy-related ascites. In the multivariate analysis, an age of ≤45 was the only independent risk factor for the occurrence of benign ascites. A small volume of pelvic ascites fluid is common in young gastric cancer patients who do not have recurrence after gastrectomy, regardless of sex. It is rare for ascites to be the first manifestation of recurrence.

Dual-Energy Computed Tomography-Based Radiomics to Predict Peritoneal Metastasis in Gastric Cancer

Objective

To develop and validate a dual-energy computed tomography (DECT) derived radiomics model to predict peritoneal metastasis (PM) in patients with gastric cancer (GC).

Methods

This retrospective study recruited 239 GC (non-PM = 174, PM = 65) patients with histopathological confirmation for peritoneal status from January 2015 to December 2019. All patients were randomly divided into a training cohort (n = 160) and a testing cohort (n = 79). Standardized iodine-uptake (IU) images and 120-kV-equivalent mixed images (simulating conventional CT images) from portal-venous and delayed phases were used for analysis. Two regions of interest (ROIs) including the peritoneal area and the primary tumor were independently delineated. Subsequently, 1691 and 1226 radiomics features were extracted from the peritoneal area and the primary tumor from IU and mixed images on each phase. Boruta and Spearman correlation analysis were used for feature selection. Three radiomics models were established, including the R_IU model for IU images, the R_MIX model for mixed images and the combined radiomics model (the R_comb model). Random forest was used to tune the optimal radiomics model. The performance of the clinical model and human experts to assess PM was also recorded.

Results

Fourteen and three radiomics features with low redundancy and high importance were extracted from the IU and mixed images, respectively. The R_IU model showed significantly better performance to predict PM than the R_MIX model in the training cohort (AUC, 0.981 vs. 0.917, p = 0.034). No improvement was observed in the R_comb model (AUC = 0.967). The R_IU model was the optimal radiomics model which showed no overfitting in the testing cohort (AUC = 0.967, p = 0.528). The R_IU model demonstrated significantly higher predictive value on peritoneal status than the clinical model and human experts in the testing cohort (AUC, 0.785, p = 0.005; AUC, 0.732, p <0.001, respectively).

Conclusion

DECT derived radiomics could serve as a non-invasive and easy-to-use biomarker to preoperatively predict PM for GC, providing opportunity for those patients to tailor appropriate treatment.

Value of Visceral Fat Area in the Preoperative Discrimination of Peritoneal Metastasis from Gastric Cancer in Patients with Different Body Mass Index: A Prospective Study

Purpose

Although peritoneal metastasis (PM) is associated with poor prognosis in gastric cancer (GC) patients, it is difficult to discriminate preoperatively. Our previous study has demonstrated visceral fat area (VFA) is a better obesity index than body mass index (BMI) in predicting abdominal metastasis. This study aimed to further explore the relationship between obesity and PM.

Patients and Methods

VFA was retrieved for 859 consecutive patients undergoing radical gastrectomy between January 1, 2009, and December 31, 2013. A receiver operating characteristic curve analysis was used to determine the BMI-specific cutoff values for VFA. Univariate and multivariate analyses evaluating the risk factors for PM at different BMI levels were performed.

Results

The optimal cutoff values for VFA were 67.28, 88.03, and 175.32 cm² for low, normal, and high BMI patients, respectively, and 18 (15.52%), 220 (40.15%), and 61 (31.28%) patients were classified as having high VFA in each group. Univariate logistic regression revealed that the association between high VFA and PM was not dependent on BMI (odds ratio [OR]=9.048, P=0.007 for low BMI, OR=3.827, P<0.001 for normal BMI, and OR=2.460, P=0.049 for high BMI). In multivariate logistic regression analysis, high VFA (OR=3.816, P<0.001) and vascular invasion (OR=1.951, P=0.039) were independent risk factors for PM only in the normal BMI group.

Conclusion

VFA only effectively predicted PM for GC patients with normal BMI, rather than those with low and high BMI. More attentions should be paid to those GC patients with high VFA and normal BMI.

Retrospective imaging studies of gastric cancer: Study protocol clinical trial (SPIRIT Compliant)

INTRODUCTION

Peritoneal metastasis (PM) is a frequent condition in patients presenting with gastric cancer, especially in younger patients with advanced tumor stages. Computer tomography (CT) is the most common noninvasive modality for preoperative staging in gastric cancer. However, the challenges of limited CT soft tissue contrast result in poor CT depiction of small peritoneal tumors. The sensitivity for detecting PM remains low. About 16% of PM are undetected. Deep learning belongs to the category of artificial intelligence and has demonstrated amazing results in medical image analyses. So far, there has been no deep learning study based on CT images for the diagnosis of PM in gastric cancer.

WE PROPOSED A HYPOTHESIS

CT images in the primary tumor region of gastric cancer had valuable information that could predict occult PM of gastric cancer, which could be extracted effectively through deep learning.

OBJECTIVE

To develop a deep learning model for accurate preoperative diagnosis of PM in gastric cancer.

METHOD

All patients with gastric cancer were retrospectively enrolled. All patients were initially diagnosed as PM negative by CT and later confirmed as positive through surgery or laparoscopy. The dataset was randomly split into training cohort (70% of all patients) and testing cohort (30% of all patients). To develop deep convolutional neural network (DCNN) models with high generalizability, 5-fold cross-validation and model ensemble were utilized. The area under the receiver operating characteristic curve, sensitivity and specificity were used to evaluate DCNN models on the testing cohort.

DISCUSSION

This study will help us know whether deep learning can improve the performance of CT in diagnosing PM in gastric cancer.

Four-Point Computed Tomography Scores for Evaluation of Occult Peritoneal Metastasis in Patients with Gastric Cancer: A Region-to-Region Comparison with Staging Laparoscopy

Background

Preoperative diagnosis of peritoneal metastasis with gastric cancer remains challenging. This study explored the abnormal computed tomography (CT) signs of occult peritoneal metastasis (OPM) and evaluated it by region-to-region comparison using staging laparoscopy, from which a 4-point CT score system was developed.

Methods

Patients with advanced gastric cancer (stage cT ≥ 2M0) diagnosed by CT were enrolled in the study. Occult peritoneal metastasis detected during staging laparoscopy was compared with preoperative CT to investigate the presence of abnormal signs by a region-to-region comparison. A 4-point CT score system was developed to define the radiologic characteristics. Subsequently, the diagnostic efficacy of the CT score system was prospectively verified.

Results

In this study, 57 OPM regions were detected by staging laparoscopy in 33 of the 385 enrolled patients. The greater omentum was the most frequent site of OPM (38.60%, 22/57), which usually exhibited a smudge-like ground-glass opacity (S-GGO) (90.91%, 20/22) with a mean CT score of 2.14. The parietal and perihepatic peritoneum was the second most common site (22.81%, 13/57). A 4-point CT score system was developed based on the results. A cutoff CT score of 2 or higher was associated with a false-negative rate of 2% (2/99). This CT score system had a sensitivity of 87.5% and a specificity of 76.4% for an OPM-positive diagnosis (area under the curve, 0.848). The agreement between two radiologists on the assigned final score was 76.2% (kappa, 0.5).

Conclusions

Patients with OPM mostly exhibited S-GGO on CT, which should be interpreted cautiously. The 4-point CT score system may improve the pretreatment evaluation of occult peritoneal metastasis, and staging laparoscopy might not be necessary for patients with a score lower than 2.

Electronic supplementary material

The online version of this article (10.1245/s10434-019-07812-y) contains supplementary material, which is available to authorized users.

Deep Convolutional Neural Network Based on Computed Tomography Images for the Preoperative Diagnosis of Occult Peritoneal Metastasis in Advanced Gastric Cancer

We aimed to develop a deep convolutional neural network (DCNN) model based on computed tomography (CT) images for the preoperative diagnosis of occult peritoneal metastasis (OPM) in advanced gastric cancer (AGC). A total of 544 patients with AGC were retrospectively enrolled. Seventy-nine patients were confirmed with OPM during surgery or laparoscopy. CT images collected during the initial visit were randomly split into a training cohort and a testing cohort for DCNN model development and performance evaluation, respectively. A conventional clinical model using multivariable logistic regression was also developed to estimate the pretest probability of OPM in patients with gastric cancer. The DCNN model showed an AUC of 0.900 (95% CI: 0.851-0.953), outperforming the conventional clinical model (AUC = 0.670, 95% CI: 0.615-0.739; p < 0.001). The proposed DCNN model demonstrated the diagnostic detection of occult PM, with a sensitivity of 81.0% and specificity of 87.5% using the cutoff value according to the Youden index. Our study shows that the proposed deep learning algorithm, developed with CT images, may be used as an effective tool to preoperatively diagnose OPM in AGC.

The Diagnostic and Prognostic Value of Digital Rectal Examination in Gastric Cancer Patients with Peritoneal Metastasis

Background: Peritoneal metastasis (PM) is the most common cause of death in gastric cancer (GC) patients. However, diagnosis of PM is still difficult in clinical practice. This study aimed to explore the diagnostic and prognostic value of digital rectal examination (DRE) in GC. Methods: 247 GC patients with PM confirmed by operation were included. The diagnostic yield of DRE compared with computed tomography (CT) was calculated. In another group of 1330 cases receiving radical gastrectomy, 38 cases with DRE (+) postoperatively were analyzed to identify risk factors. A nomogram was constructed to predict postoperative DRE (+). Results: The specificity, positive predictive value and positive likelihood ratio of DRE in diagnosis of PM was 99.8%, 91.2% and 58.4, higher than CT (97.6%, 64.9% and 10.4). Though the sensitivity of DRE (12.6%) was lower than CT (24.7%), 17 of 31 patients with DRE (+) could not be found by CT. Moreover, the overall survival of confirmed PM patients with DRE (+) (PM-DRE (+)) was much lower than PM-DRE (-) patients (P<0.001). In addition, the nomogram to predict postoperative DRE (+) had a bootstrap-corrected concordance index of 0.73 and was well calibrated. Conclusions: GC patients with DRE (+) could be regarded as a special subtype of stage IV ones with poorer prognosis. Supply of palliative care and chemotherapy rather than unnecessary operation might be a better alternative for these patients. DRE was an effective supplement for CT and should be generally recommended for GC patients.

Clinical significance of computed tomography-detected ascites in gastric cancer patients with peritoneal metastases

Patients with peritoneal metastases (PM) are generally considered incurable; therefore, the presence of PM is a critical factor in deciding between palliative surgery and curative resection as a therapeutic strategy. Previous studies have not determined the predictive value of ascites detected on computed tomography (CT) for the presence of PM. We aimed to analyze the factors that are associated with PM in patients with CT-detected ascites.A total of 2207 consecutive patients who were diagnosed with gastric cancer between 2004 and 2013 were identified. Eleven patients with liver cirrhosis or chronic renal insufficiency with ascites and 57 patients who received previous treatment were excluded. Ninety-eight patients who had definite evidence of distant metastasis or PM on CT and 64 patients who did not undergo surgery were excluded. A total of 91 patients were enrolled in the study to analyze the association between CT-detected ascites and surgically confirmed PM.Seventy-six patients underwent curative resection and 15 patients underwent palliative surgery. Twelve patients exhibited peritoneal seeding and 37 patients showed regional lymph node metastasis. Regional lymph node metastasis, advanced gastric cancer, undifferentiated pathology, and the amount of ascites were significantly associated with PM. Multivariable logistic regression analysis identified the amount of ascites to be an independent risk factor for the presence of PM.Regional lymph node metastasis, advanced gastric cancer, undifferentiated pathology, and the amount of ascites were associated with PM. The amount of ascites was found to be an independent risk factor for PM.

Computed tomographic characteristics for patients with unresectable gastric cancer harboring low-volume peritoneal carcinomatosis

Although current staging workups could differentiate most patients with operable from inoperable advanced gastric cancers, there are still some patients with low-volume peritoneal carcinomatosis, defined as only metastasis with multiple subcentimeter lesions in peritoneum, receiving unnecessary open-close procedures. The computed tomography (CT) of the patients with unresectable advanced gastric cancer harboring low-volume peritoneal carcinomatosis was retrospectively identified and then thoroughly reviewed by two independent radiologists unaware of the peritoneal carcinomatosis status. Of the 798 patients with newly diagnosed gastric cancer between January 2007 and December 2010, 52 patients harboring advanced gastric cancer with low-volume peritoneal carcinomatosis receiving surgery with curative intent were identified. Descriptive statistic was used for the radiologic characteristics. The most common radiologic characteristic of CT was omental fat stranding (57.7%), followed by omental clustered subcentimeter nodules (53.8%), distant enlarged lymph node (40.4%), distant grouping of small lymph nodes (36.5%), peritoneal nodules or thickening (34.6%), minimal loculated ascites (21.2%), intestinal wall thickening or irregularity (9.6%), and hydronephrosis or hydroureter without stone or urothelial lesion (5.8%). Comprehensively reviewing the radiologic characteristics of CT may identify the patients harboring advanced gastric cancer with low-volume peritoneal carcinomatosis.

Evaluation and treatment of malignant ascites secondary to gastric cancer

Malignant ascites affects approximately 10% of patients with gastric cancer (GC), and poses significant difficulties for both patients and clinicians. In addition to the dismal general condition of affected patients and the diversity of associated complications such as jaundice and ileus, problems in assessing scattered tumors have hampered the expansion of clinical trials for this condition. However, the accumulation of reported studies is starting to indicate that the weak response to treatment in GC patients with malignant ascites is more relevant to their poor prognosis rather than to the ascites volume at diagnosis. Therefore, precise assessment of initial state of ascites, repetitive evaluation of treatment efficacy, selection of suitable treatment, and swift transition to other treatment options as needed are paramount to maximizing patient benefit. Accurately determining ascites volume is the crucial first step in clinically treating a patient with malignant ascites. Ultrasonography is commonly used to identify the existence of ascites, and several methods have been proposed to estimate ascites volume. Reportedly, the sum of the depth of ascites at five points (named “five-point method”) on three panels of computed tomography images is well correlated to the actual ascites volume and/or abdominal girth. This method is already suited to repetitive assessment due to its convenience compared to the conventional volume rendering method. Meanwhile, a new concept, “Clinical Benefit Response in GC (CBR-GC)”, was recently introduced to measure the efficacy of chemotherapy for malignant ascites of GC. CBR-GC is a simple and reliable patient-oriented evaluation system based on changes in performance status and ascites, and is expected to become an important clinical endpoint in future clinical trials. The principal of treatment for GC patients with ascites is palliation and prevention of ascites-related symptoms. The treatment options are various, including a standard treatment based on the available guidelines, cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC), laparoscopic HIPEC alone, intravenous chemotherapy, intraperitoneal chemotherapy, and molecular targeting therapy. Although each treatment option is valid, further research is imperative to establish the optimal choice for each patient.

CT imaging of peritoneal carcinomatosis and its mimics

Invasive peritoneal disease includes more than just peritoneal carcinomatosis. Although this is the most common aetiology, especially when a primary is found, other conditions may be responsible for peritoneal invasion. A rigorous analysis of CT features taken together with the clinical and biological context usually allows the main differential diagnoses, which entail different types of management, to be drawn out. Pseudomyxoma peritonei, peritoneal lymphomatosis, tuberculosis, peritoneal mesothelioma, diffuse peritoneal leiomyomatosis, and benign splenosis are the main differential diagnoses.

Clinical significance of serum CA-125 in Korean females with ascites

PURPOSE

Mycobacterium tuberculosis is endemic in Korea. Because tuberculous peritonitis is characterized by ascites, abdominal pain, abdominal mass and elevation of serum CA-125, it can be confused with ovarian malignancies. The aim of this study was to evaluate the significance of serum CA-125 level in the differential diagnosis of tuberculous peritonitis and ovarian malignancy in a Mycobacterium tuberculosis-endemic area.

MATERIALS AND METHODS

The medical records of patients diagnosed with tuberculous peritonitis (n=48) or epithelial ovarian malignancy (n=370) at Samsung Medical Center from January 2000 to October 2009 were retrospectively reviewed.

RESULTS

Median serum CA-125 level in the epithelial ovarian cancer group was significantly higher than that in the tuberculous peritonitis group (p ≤ 0.01). Only one patient (2.1%) in the tuberculous peritonitis group had a serum CA-125 level over 2000 U/mL. However, 109 patients (29.5%) in the epithelial ovarian cancer group had a serum CA-125 level over 2000 U/mL. At the CA-125 ranges of 400 to 599 and 600 to 799, the proportions of those with tuberculous peritonitis were 24% and 21.9%, respectively. At a serum CA-125 level over 1000 U/mL, however, the proportion of tuberculous peritonitis was much lower (2.1%).

CONCLUSION

Tuberculous peritonitis should be considered in the evaluation of female patients with ascites and high serum CA-125.

Gastric cancer: imaging and staging with MDCT based on the 7th AJCC guidelines

Gastric cancer is a common deadly cancer worldwide. The tumor-node-metastasis (TNM) staging system is one of the most commonly used staging systems, and is accepted and maintained by the International Union against Cancer (UICC) and the American Joint Committee on Cancer (AJCC). The TNM system is well known to effectively predict the prognosis of gastric cancer patients. The latest revision of TNM staging was presented in the 7th edition of the AJCC in 2009. Multi-detector row CT (MDCT) is a powerful test for non-invasive evaluation and can assess metastatic and locoregional staging simultaneously. Current MDCT with isotropic imaging and 3D images has increased the accuracy of T and N staging in patients with gastric cancer. Multi-planar reformatted images permit the radiologist to select the optimal imaging plane to accurately evaluate tumor invasion depth of the gastric wall and perigastric infiltration to identify a fat plane between a tumor and adjacent organs, to avoid partial volume averaging effects, and to differentiate lymph nodes from small perigastric vessels. Thus, MDCT provides a useful all-in-one diagnostic method for the pre-operative evaluation of patients with known, or strongly suspected, gastric cancer according to the 7th AJCC TNM staging system.

MELD-sodium score and its prognostic value in malignancy-related ascites of pancreatic and gastric cancer

BACKGROUND

Malignant ascites is a manifestation of end-stage events in a variety of cancers. There is significant lack of possible survival predictors in patients with malignancy-related ascites. Since the Model for End-Stage Liver Disease (MELD)-Na score has been shown to be a feasible and independent prognostic predictor for both short- and long-term outcome in HCC patients, we decided to test its prognostic role in other cancer types with ascites.

MATERIAL AND METHODS

This is a retrospective study. The outpatient oncology clinic's records were screened for the period between 2004 and 2011. Eighty-two pancreatic and gastric cancer patients were enrolled into the study.

RESULTS

The median age of patients was 59 (±12). Fifty-nine patients had gastric cancer and 23 had pancreatic cancer. Overall survival (OS) was 16.8 (IR, 1-98) months in gastric cancer and 16.3 (IR, 0.5-81) months in pancreatic cancer. There was no statistically significant difference between OS of gastric and pancreatic cancer. Progression-free survival (PFS) was statistically significantly longer in gastric cancer than pancreatic cancer with 16.5 (IR, 0.5-90) vs 6.5 (IR, 0.4-34) months (P = 0.04). Further analysis of data included stepwise multiple regression analysis with the dependent variable "overall survival." The model had two independent predictors and an R(2) of 82 % and a predicted R(2) of 81 %. Predictors for time to remission were PFS and MELD-Na. The regression equation for the model was: Overall survival =17.4- 0.522 MELD-Na + 0.902 PFS CONCLUSION: In this study we showed that progression-free survival and MELD-Na score are significantly related with overall survival. MELD-Na score can be one of the predictors of the survival and PFS in pancreatic and gastric cancer patients with ascites.

Prognostic significance of computed tomography defined ascites in advanced gastric cancer

PURPOSE

The aim of this study was to investigate the clinicopathologic features and prognosis in patients with computed tomography (CT) findings of ascites, with a focus on the correlation with peritoneal carcinomatosis.

METHODS

This study included a total of 157 patients who underwent surgery for advanced gastric cancer from 2003 to 2008 at the Department of Surgery, Hallym University Kangdong Sacred Heart Hospital, Seoul, Korea, which were analyzed retrospectively.

RESULTS

Fourteen patients (8.9%) presented ascites on their CT scan. Among them, 10 patients had peritoneal carcinomatosis, and showed significant difference with CT ascites positive group in the incidence of peritoneal carcinomatosis. The presence of CT ascites was significantly correlated with pathologic T stage, tumor size, histologic type, CT T and N stages, CT peritoneal nodularity and curability of surgery, statistically. The prognosis of CT ascites positive group was much poorer in the total advanced gastric cancer patients (P < 0.001), as well as in patients with pathologic T4 (P = 0.002). Also in patients without peritoneal carcinomatosis, CT ascites positive subgroup tended to have a worse prognosis than CT ascites negative subgroup (P = 0.086). Tumor size, CT T and N stages and the presence of CT peritoneal nodularity and ascites influenced the prognosis significantly; among which, if a tumor size larger than 5 cm, CT T4 stage and the presence of CT ascites were identified as independent prognostic factors.

CONCLUSION

The presence of ascites was closely associated with peritoneal metastasis, and was the most significant independent prognostic factor in advanced gastric cancer in the present study.

[Diagnostic imaging in oncology--evidence reviews for evidence based guidelines by the Agency of Quality for Medicine (ÄZQ)]

Within the context of the development of evidence-based oncology guidelines, the Agency for Quality in Medicine undertook evidence reviews for diagnostic imaging procedures. Systematic searches retrieved no randomised controlled trials, but only cohort studies and case series of mostly moderate quality. The identified studies provided only a restricted basis for the guideline recommendations as their validity was limited and only outcomes of diagnostic accuracy were examined. However, decision criteria for recommending diagnostic strategies significantly comprise judgements about required resources and availability of diagnostic imaging procedures. These criteria as well as patient out-comes were mostly implicit and should be explicated in future. In order to increase the relevance of evidence reviews for oncological diagnosis, high quality studies which examine resources and patient-centred outcomes for diagnostic strategies are required.

Peritoneal metastasis: detection with 16- or 64-detector row CT in patients undergoing surgery for gastric cancer

PURPOSE

To retrospectively measure the diagnostic performance of prospective computed tomographic (CT) results obtained by using 16- or 64-detector row scanners in the detection of peritoneal metastases (PMs) in patients with advanced gastric cancer.

MATERIALS AND METHODS

The institutional review board approved this retrospective study and waived the need to obtain patient consent. In 498 patients with gastric cancer (stage >or= T2) who were undergoing surgery, the presence of PM was prospectively rated as grade 0 (absent), grade 1 (equivocal), or grade 2 (present) on CT scans (0.67 or 2 mm thick) that were interpreted by interactively adjusting the viewing thickness and viewing plane. The CT readings were retrospectively compared with surgical and pathologic findings. In patients in whom the presence of PM was rated as grade 1 or less, factors predictive of PM were identified by testing variables, including patient and tumor characteristics, with univariate tests and multivariate logistic regression analysis.

RESULTS

Fifty-three patients (10.6%) had confirmed PM. When only grade 2 was considered to indicate a positive CT reading, sensitivity and specificity were 28.3% (15 of 53) and 98.9% (440 of 445), respectively. With the threshold of grade 1 or greater indicating a positive reading, sensitivity and specificity were 50.9% (27 of 53) and 96.2% (428 of 445), respectively. In the patients with grades of 1 or less, the significant factors predictive of PM were greater tumor size and T stage.

CONCLUSION

The sensitivity of PM detection is limited, even with modern CT techniques. In patients whose CT results are not definitely positive for PM, staging laparoscopy is still recommended if the aforementioned two predictive factors (greater tumor size and T stage) are suspected.

Helical CT evaluation of the preoperative staging of gastric cancer in the remnant stomach

OBJECTIVE

The objective of our study was to evaluate the diagnostic performance of helical CT for evaluating the preoperative staging of gastric cancer in the remnant stomach.

MATERIALS AND METHODS

Preoperative helical CT images of 67 patients with gastric cancer in the remnant stomach were independently analyzed regarding staging of the tumor by two radiologists who were blinded to histopathologic and surgical results. The differences in their assessments were resolved by consensus including the opinion of a third radiologist. The radiologists were asked to determine the depth of tumor invasion of the gastric wall (T stage), classifying it as </= T2, T3, or T4; local lymph node involvement (N stage); and solid organ metastasis or peritoneal involvement (M stage). TNM staging on CT was correlated with the histopathologic results of the resected specimen or with the surgical findings. Interobserver agreement was assessed using weighted kappa statistics.

RESULTS

The overall accuracy of T staging for reviewers 1 and 2 and for the consensus reading were 83.6%, 78.2%, and 85.4%, respectively. Five of 34 </= T2 lesions were misdiagnosed as T3. The cause of the overstaging was the misconception of the postoperative fibrotic change of the anastomotic site as perigastric tumoral infiltration. Three of 18 T4 lesions were understaged because of inadequate gastric distention (n = 1) and misinterpretation of adjacent organ involvement as partial volume averaging (n = 2). The accuracy of N staging and M staging were 81.8% and 94.0% for reviewer 1; 78.2% and 91.0% for reviewer 2; and 81.8% and 94.0% for the consensus reading, respectively. The weighted kappa values of T staging, N staging, and M staging were 0.676, 0.619, and 0.924, respectively.

CONCLUSION

Contrast-enhanced helical CT can be used successfully to preoperatively evaluate the staging of remnant stomach cancer in patients who have undergone previous gastric resection.