CT's capability in detecting advanced gastric cancer

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.

MRI of gastric carcinoma: Results of T and N-staging in an in vitro study

AIM: To determine the accuracy of 1.5-T magnetic resonance imaging (MRI) in the evaluation of gastric wall invasion and perigastric lymph node metastasis in gastric adenocarcinoma.

METHODS: Twenty resected gastric specimens containing 20 tumors were studied with a 1.5-T MR system using a commercial head surface coil. MR scanning was performed with a T1 weighted image (TR/TE = 500/20), and a T2 weighted image (TR/TE = 2500/90). MR findings were compared with pathologic findings.

RESULTS: A T1-weighted image demonstrated three layers in the normal gastric wall. All of the gastric tumors were well demonstrated by lesions and location. In a MRI findings of gastric wall invasion, there was 1 case of T1, 7 of T2, 11 of T3. Pathologic results of resected specimens included 3 cases of pT1, 4 of pT2, and 12 of pT3. The accuracy of T staging with MRI was 74% (14 of 19). MRI findings of lymph node metastasis included 6 cases of N0, 13 cases of N1. The accuracy of the N staging with MRI was 47% (9 of 19).

CONCLUSION: MRI has a high diagnostic accuracy in the evaluation of the T staging of gastric cancer in vitro and thus potentially enables preoperative histopathologic staging.

Gastric Adenocarcinoma: Is Computed Tomography (CT) Useful in Preoperative Staging?

BACKGROUND AND PURPOSE

Although multiple studies testing the accuracy of CT in the preoperative staging of gastric adenocarcinoma have been carried out, their results are controversial. Whilst some authors claim that CT is an accurate method for preoperatively staging gastric cancer, others have advocated the contrary. Because of this discrepancy we have retrospectively reviewed preoperative CT findings compared with histopathological results in patients with gastric adenocarcinoma.

PATIENTS AND METHODS

Seventy-two patients diagnosed with gastric cancer who underwent potentially curative surgery and preoperative staging CT of quality were included in the study. The size, gastric wall thickening, presence of lymphadenopathy, adjacent organ invasion and location of the gastric mass was recorded. Early tumors (T1 and T2) and more advanced tumors (T3 and T4) were grouped together. CT staging was correlated with the final histopathological stage (TNM). The global results were expressed as sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV).

RESULTS

Seventy-two cases were included with fifty-five being male and a median age of 67 years (range 33-91). CT correctly identified the location of the tumor in 56 (53% antropyloric, 18% subcardial). Median time from CT scan to surgery was fourteen days (range 2-49). In T detection: T1/T2 and T3/T4 with sensitivity of 70% and 61%. Lymph node involvement: Sensitivity 49%. Overstaged in 47% Understaged in 75%. Specificity of 53%. Nine patients with colon-mesocolon (5 patients) and pancreas (4 patients) invasion. Sensitivity 44% and specificity 96%.

CONCLUSION

Spiral CT is not an accurate method in predicting preoperative stages in gastric cancer.

CT and PET in stomach cancer: preoperative staging and monitoring of response to therapy

Stomach cancer is one of the leading causes of cancer mortality worldwide. Complete resection of a gastric tumor and adjacent lymph nodes represents the only potentially curative intervention. Computed tomography (CT) has remained the modality of choice for the preoperative staging of gastric cancer and for follow-up. A recently developed advanced CT technique that makes use of thin sections, optimal contrast material enhancement, and multiplanar reformation allows more accurate staging. However, CT may be limited in the identification of nonenlarged lymph node metastasis, peritoneal dissemination, and small hematogenous metastasis. Positron emission tomography (PET) with 2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) has been recognized as a useful diagnostic technique in clinical oncology. FDG PET allows scanning of a larger volume than is possible with CT. Although FDG PET is not an appropriate first-line diagnostic procedure in the detection of stomach cancer and is not helpful in tumor staging, it may play a valuable role in the detection of distant metastases, such as those of the liver, lungs, adrenal glands, ovaries, and skeleton. FDG PET may also be helpful in the follow-up of patients undergoing chemotherapy, as it allows the identification of early response to treatment. Further studies are needed to determine the efficacy of FDG PET in the detection of local nodal metastases and peritoneal dissemination. Nevertheless, the combined use of CT and PET can be helpful in the preoperative staging of stomach cancer and in the therapeutic monitoring of affected patients.

Preoperative evaluation of the curative resectability of gastric cancer by abdominal computed tomography and ultrasonography: a prospective comparison study

OBJECTIVES

We compared the ability of preoperative abdominal computed tomography (CT) with that of preoperative abdominal ultrasonography (US) in predicting the extent of tumor growth and the curative resectability of gastric cancer.

METHODS

Abdominal CT and US were done in 95 patients with gastric adeno-carcinoma. The radiologic findings were prospectively compared with surgical and pathologic findings.

RESULTS

The sensitivities of abdominal CT and US in detecting the perigastric lymph node involvement were 26.6% and 20%, respectively. The sensitivity of abdominal CT in predicting the pancreatic invasion (60%) was better than that of abdominal US (20%). However, there were 6 false positive diagnosis of pancreatic invasion by abdominal CT; in contrast, there was no false positive diagnosis of pancreatic invasion by abdominal US. Of 95 patients who underwent surgical exploration, 14 were found to have unresectable tumors because of extragastric organ involvement and distant metastases. Abdominal CT falsely predicted 8 of 14 cases in which curative gastric resection was impossible as resectable. Moreover, abdominal CT falsely predicted 5 of 81 cases in which curative gastric resection was possible as unresectable. Abdominal US falsely predicted 12 of 14 cases in which curative surgery was impossible as resectable.

CONCLUSION

Preoperative abdominal Ct and US did not accurately predict the tumor extent and the curative resectability of the gastric cancer. Especially, abdominal CT finding of pancreatic invasion by gastric cancer should not be a contraindication for surgical exploration.

Hydro-CT in patients with gastric cancer: preoperative radiologic staging

A total of 35 patients (age range 35-78 years) with gastric tumors on the lesser curve, or in the antro-pyloric region, underwent angio-CT in the prone position after filling the stomach with 500 ml of water and intravenous administration of glucagon. The films were reviewed by three radiologists independently, staging each tumor according to the TNM classification preoperatively. The overall accuracy of tumor staging ranged between 66-77 %, overstaging between 17-25 %, and understaging between 3-8.5 %. The diagnostic sensitivity, specificity, and accuracy for serosal invasion ranged between 90 and 100, 76 and 84, and 80-88 %, respectively, and the overall accuracy for N staging was 46, 48, and 51 % for the three observers. If, however, N1 and N2 tumors were considered as a single group, N-stage accuracy increased, ranging between 63 and 77 %. The "K test" for analyzing the interobserver agreement was 60 %, i. e., the diagnostic results are reproducible. Water filling of the stomach optimizes visualization of the gastric wall on contrast-enhanced CT. The prone position and drug-induced hypotony allows for good distension without any disturbing artifact reduction obscuring the lower gastric body.

Use of water or air as oral contrast media for computed tomographic study of the gastric wall: comparison of the two techniques

Thirty-four patients with a high suspicion of gastric lesion at endoscopy were studied by two computed tomographic (CT) techniques: one using a gas-producing agent and the other using water as an oral contrast media. Intravenous contrast medium was also given in all patients who underwent the water technique. Final histologic proof was obtained either by endoscopy or at surgery. Both CT techniques detected the wall abnormality in 32 of the 34 patients, and both techniques missed the same lesion in two patients. The water technique showed more gastric wall details and the lesion's limits could be defined more accurately. The acceptance and tolerance of the gas-producing agent was better in severely ill patients than tap water.

Use of water or air as oral contrast media for computed tomographic study of the gastric wall: comparison of the two techniques

Thirty-four patients with a high suspicion of gastric lesion at endoscopy were studied by two computed tomographic (CT) techniques: one using a gas-producing agent and the other using water as an oral contrast media. Intravenous contrast medium was also given in all patients who underwent the water technique. Final histologic proof was obtained either by endoscopy or at surgery. Both CT techniques detected the wall abnormality in 32 of the 34 patients, and both techniques missed the same lesion in two patients. The water technique showed more gastric wall details and the lesion's limits could be defined more accurately. The acceptance and tolerance of the gas-producing agent was better in severely ill patients than tap water.

Computed tomography in the preoperative evaluation of gastric carcinoma

Computed tomography (CT) of the abdomen was done in 49 patients with gastric carcinoma. These cases were retrospectively staged and evaluated as to operability. Various staging parameters were also evaluated separately. The results were correlated to findings on surgery, liver scan, and cytology. Overall accuracy of CT staging and operability assessment was 72 and 82%, respectively. Among the various CT parameters, perigastric fat invasion had a positive predictive value of 91%. The demonstration of local node involvement and invasion of adjacent organs was unreliable. Since surgery is currently the only treatment for gastric carcinoma, CT staging has limited clinical value. The principal role of CT is in the assessment of operability in patients with carcinoma of the stomach.