Local recurrence after surgery for gastric carcinoma: CT findings

Diagnostic role of 18F-FDG PET/CT in recurrence detection of surgically treated gastric cancer: a cross-sectional study

Background

Radical surgery of gastric cancer is considered as the only curative treatment; however, its poor long-term survival is often occurred due to its recurrence either local and/or distant metastasis. Thus, early detection of recurrence helps in improving the prognosis. Our aim is to assess the diagnostic role of 18F-FDG PET/CT for detecting postoperative recurrence in gastric cancer patients who have a radiological and/or clinical suspicion of recurrence.

Results

The study was carried over 31 males (62%) and 19 females (38%) pathologically proven with gastric carcinoma and underwent surgical intervention. All patients underwent PET/CT scan where the site and number of positive FDG activity analyzed. The sensitivity, specificity, and accuracy for locoregional recurrence were 75%, 81.58%, and 85% with p value 0.001; for regional lymph node recurrence were 100%, 100%, and 100% with p value < 0.001; for liver metastasis were 100%, 100%, and 100% with p value < 0.001; for peritoneum metastasis were 100%, 97.38%, and 98% with p value < 0.001; and for distant metastasis were 100%, 85.7%, and 94% with p value < 0.001.

Conclusion

With agreements to many studies, this study confirms that FDG PET/CT is a highly effective modality for postoperative surveillance detection of recurrent gastric cancer, especially in patients with clinically manifested disease, elevated tumor markers, and an indication of distant metastasis at diagnostic CT.

The Relevance of Serosal Exposure Without Nodal Metastasis in Resectional Gastric Cancer

BACKGROUND

According to 8th AJCC/UICC TNM criteria, stage IIB includes pT1N3M0, pT2N2M0, pT3N1M0, and pT4aN0M0, which includes not only early gastric cancer but also locally advanced cancer. There are currently no data about whether there is any additional impact of serosal exposed cancer without nodal metastasis (pT4aN0) on patients' survival outcomes compared with other subgroups in IIB.

METHODS

Patients who underwent radical gastrectomy for gastric cancer patients were enrolled, including 427 patients in stage IIB; 20 (4.68%), 104 (24.35%), 172 (40.28%), and 131 (30.67%) patients were classified as pT1N3a, pT2N2, pT3N1, and pT4aN0, respectively. Clinicopathological characteristics, recurrence pattern, and survival and recurrence rates were analyzed according to the TNM subgroups.

RESULTS

Cancer-specific and relapse-free survival were significantly worse in serosal exposed cancer than in nonserosal exposed cancer in stage IIB (P = 0.019 and P = 0.015). Recurrence rate was highest in the pT4aN0 subgroup (29.0%) in stage IIB, and peritoneal metastasis was the most common pattern. Survival outcomes of the pT4aN0 subgroup were not significantly different from those of the stage IIIA or pT4aN1 subgroups.

CONCLUSIONS

Patients with serosal exposed cancer without nodal metastasis shows worse cancer specific and disease-free survival with higher incidence of peritoneal metastasis than other subgroups in stage IIB. Further surveillance studies, including staging laparoscopy and active adjuvant therapy, are required in this subgroup of patients.

Evaluation of recurrence in gastric carcinoma: Comparison of contrast-enhanced computed tomography and positron emission tomography/computed tomography

AIM

To compare the value of contrast-enhanced abdominal computed tomography (CT) and fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for detecting gastric carcinoma recurrence.

METHODS

We retrospectively examined data from 2475 patients who underwent both contrast-enhanced abdominal CT and FDG PET/CT for the surveillance of gastric carcinoma curative resection. Patients had an interval of less than 1 mo between their CT and PET/CT scans. Sixty patients who had recurrence were enrolled. Among 1896 patients who did not have recurrence, 60 were selected by simple random sampling. All CT and PET/CT images were reviewed retrospectively by two reviewers blinded to all clinical and pathologic information except curative resection due to gastric carcinoma.

RESULTS

The pathological stage of the recurrence group was statistically significantly higher than that of the control group (P < 0.001). In the 60 patients who had recurrence, there were 79 recurrent lesions. Forty-four patients had only one location of recurrence, 13 patients had two locations, and 3 patients had three. In the detection of patient-based overall recurrence, no statistically significant differences existed between the two modalities (P = 0.096). However, for peritoneal carcinomatosis, CT had a statistically significantly higher sensitivity compared to PET/CT (96% vs 50%, P = 0.001). Adenocarcinoma was the most common type of gastric carcinoma. On the pathology-based analysis, CT also had a statistically significantly higher sensitivity compared to PET/CT (98% vs 80%, P = 0.035).

CONCLUSION

Contrast-enhanced CT was superior to PET/CT in the detection of peritoneal carcinomatosis and pathologic type of adenocarcinoma.

Surveillance for Gastric Cancer

This article discusses the current National Comprehensive Cancer Network guidelines and other available Western and Eastern guidelines for the surveillance of gastric cancer following surgical resection. It reviews the literature assessing the utility of intensive surveillance strategies for gastric cancer, which fails to show an improvement in survival. The unique issues relating to follow-up of early gastric cancer and after endoscopic resection of early gastric cancer are discussed. This article also reviews the available modalities for follow-up. In addition, it briefly discusses the advancements in treatment of recurrent and metastatic disease and the implications for gastric cancer survival and surveillance strategies.

The Role of 18F-FDG PET/CT in the Evaluation of Gastric Cancer Recurrence

Objective: F-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-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. This study aimed to assess the diagnostic performance of 18F-FDG PET/CT for detecting recurrence in gastric cancer patients with radiologic or clinical suspicion of recurrence and its clinical impact on making decision.

Methods: We performed a retrospective review of 130 consecutive patients who underwent PET/CT scans for post-treatment surveillance of gastric cancer between January 2008 and March 2012. The mean time between the initial diagnosis of gastric cancer and PET/CT studies was 44 weeks with a median of 18 weeks. The number and site of positive FDG uptake were analyzed and correlated with the final diagnosis by calculating the diagnostic values. We evaluated the diagnostic accuracy of PET/CT for detecting the recurrence in terms of whether or not histology had been SRC/musinous adenocarcinoma. The changes in the clinical management of patients were also evaluated according to the results of PET/CT.

Results: Of all 130 patients, 91 patients were confirmed to have true recurrence. The sensitivity, specificity, positive predictive value, negative predictive value and the accuracy of PET/CT for diagnosing true recurrence on a per-person basis were 91.2%, 61.5%, 84.6%, 75.0% and 82.3% respectively. Final diagnoses were confirmed histopathologically in 59 (45.4%) of 130 patients and by clinical and radiological follow-up in the remaining 71 (54.6%) patients. In the subgroup with SRC/mucinous adenocarcinoma differentiation of the primary tumor, there was no statistically significant difference in terms of diagnostic accuracy of PET/CT on a per-person basis. In addition, PET/CT results changed the patients’ management in 20 (15%) cases.

Conclusions: 18F-FDG PET/CT can provide useful information in discriminating true recurrence in patients with suspected gastric cancer recurrence and may have significant impact on clinical decisions/patient management in a considerable percentage of patients.

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.

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.

Using multidetector-row CT for the diagnosis of afferent loop syndrome following gastroenterostomy reconstruction

PURPOSE

To assess the clinical manifestations and multidetector-row computed tomography (MDCT) findings of afferent loop syndrome (ALS) and to determine the role of MDCT on treatment decisions.

MATERIALS AND METHODS

From January 2004 to December 2008, 1,100 patients had undergone gastroenterostomy reconstruction in our institution. Of these, 22 (2%) patients were diagnosed as ALS after surgery that included Roux-en-Y gastroenterotomy (n=9), Billroth-II gastrojejunostomy (n=7), and Whipple's operation (n=6). Clinical manifestations and MDCT features of these patients were recorded and statistically analyzed. The presumed etiologies of obstruction shown on the MDCT were correlated with clinical information and confirmed by surgery or endoscopic biopsy.

RESULTS

The most common clinical symptom was acute abdominal pain, presenting in 18 patients (82%). We found that a fluid-filled C-shaped afferent loop in combination with valvulae conniventes projecting into the lumen was the most common MDCT features of ALS. Malignant causes of ALS, such as local recurrence and carcinomatosis, are the most common etiologies of obstruction. These etiologies and associated complications can be predicted 100% by MDCT.

CONCLUSION

Our results suggest that MDCT is a reliable modality for assessing the etiologies of ALS and guiding treatment decisions.

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.

Detecting recurrence of gastric cancer: the value of FDG PET/CT

PURPOSE

In order to assess the diagnostic performance of Positron emission tomography/Computed tomography (PET/CT) for detecting recurrence in gastric cancer patients with clinical or radiologic suspicion of recurrence after surgical resection.

MATERIALS AND METHODS

Over a 4-year period, 105 post-operative patients with gastric cancer, who underwent PET/CT due to clinical or radiologic suspicion of recurrence during follow-up, were collected after confirming their PET/CT findings. The number and site of positive FDG uptake were retrospectively analyzed, and were correlated with the final diagnosis, by calculating the diagnostic values and assessing the causes of misdiagnosis.

RESULTS

Of all 105 patients, 75 patients were confirmed to have true recurrence with 108 recurrence sites. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy for diagnosing true recurrence on a per-person basis were 75%, 77%, 89%, 55%, and 75%, respectively. On a per-lesion basis, 75 (69%) of 108 true recurrences showed positive FDG uptake, while 75 (89%) of 84 positive FDG uptake was confirmed to have true recurrence.

CONCLUSION

PET/CT was relatively accurate in detecting recurrence in post-operative patients with gastric cancer. Moreover, PET/CT might be helpful in confirming the presence of recurrence particularly in patients who were highly suspicious of recurrence, because of its high positive predictability.

Follow-up strategy after curative resection of gastric cancer: a nationwide survey in Korea

BACKGROUND

To date, guidelines for follow-up after curative resection in patients with gastric cancer have not been reported. Thus, most centers have managed the process according to institution-specific protocols. We investigated current follow-up practices after curative resection of gastric cancer using a nationwide survey in Korea, where gastric cancer is epidemic.

METHODS

From July to September 2007, questionnaires were sent out to 205 members of the Korean Gastric Cancer Association (KGCA). The questionnaire packet contained a covering letter, general information, and a questionnaire about follow-up schedules and methodologies.

RESULTS

Forty-six percent (96/205) of the members of the KGCA returned the survey. The majority of responders indicated that patients with early gastric cancer were followed up every 6 months (64.4%) for the first year, every 12 months (47.9%) for the next 4 years, and every 12 months (68.8%) from the fifth year after surgery on. For patients with advanced gastric cancer, follow-up studies were carried out every 3 months (43.8%) for the first year, every 6 months for the next 4 years, and every 12 months (75.0%) from the fifth year onward. After surgery, most responders used computed tomography for imaging, carcinoembryonic antigen (CEA) and carbohydrate antigen (CA)19-9 as tumor markers, and serum iron among follow-up measures.

CONCLUSIONS

Clinicians have a variety of approaches regarding the extent of follow-up and methodologies used after curative resection for gastric cancer. Therefore, a multicenter randomized trial will be needed to compare routine follow-up with intensive schedules. Our results could facilitate the design of such studies.

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.

Foreign body granuloma of activated charcoal

We present foreign body granulomas induced by activated charcoal from intraperitoneal chemotherapy and mimicked peritoneal metastases in the patients with gastric cancer. On CT, they were manifested as a peritoneal mass or thickening with variable shapes, including oval, round, bizarre, linear and even a molded shape due to where they were lodged, such as the pelvis and paracolic gutter. All the lesions showed high attenuation relative to muscle on the precontrast CT and showed positive findings on PET/CT.

Differentiating Malignant From Benign Wall Thickening in Postoperative Stomach Using Helical Computed Tomography

OBJECTIVE

To determine significant computed tomography (CT) predictors for differentiating malignant from benign wall thickening in postoperative stomach.

METHODS

Sixty-nine patients with perianastomotic wall thickening (25 malignant, 44 benign) after gastric surgery were identified. All patients underwent contrast-enhanced CT with the administration of oral contrast agents such as air, diluted barium, or water. Two radiologists analyzed CT images regarding enhancement of thickened wall, obliteration of wall layering, heterogeneity, asymmetry, perigastric infiltration, proximity to metallic suture material, lymphadenopathy, adjacent bowel thickening, and periceliac soft-tissue density. Another radiologist measured the wall thickness and the mean CT value of the lesion and normal mucosa. Individual CT findings relevant as predictors were determined using the univariate test. Multivariate analysis was used to determine the most predictable factors.

RESULTS

Malignant wall thickening was significantly thicker than benign one. Isoattenuation and high attenuation of thickened wall were more frequently seen in malignant than in benign cases. Multivariate analysis showed that isoattenuation or high attenuation of thickened wall, proximity to suture material, and perigastric infiltration were only 3 variables that independently differentiated malignant from benign thickening in postoperative stomach.

CONCLUSION

Isoattenuation or high attenuation of thickened wall, perigastric infiltration, and wall thickening without metallic suture material are the 3 main factors distinguishing malignant from benign thickening in postoperative stomach.

Follow-up of gastric cancer: a review

Although there is broad agreement in the staging, classification, and surgery for gastric cancer, there is no consensus regarding follow-up after gastrectomy. Follow-up varies from investigations on clinical suspicion of relapse to intensive investigations to detect recurrences early, assuming that this improves survival and quality of life. Advanced gastric cancers recur mainly by locoregional recurrence or distant metastasis. Local recurrences detected at endoscopy or on computed tomography (CT) are invariably incurable. For early gastric cancers, endoscopy can detect new primaries, but the incidence of these tumors is low, and many thousands of procedures are required to detect each operable case. CT is much better at detecting liver metastasis and, although these are usually multiple and unresectable, there are several reports of good survival following liver resection for isolated metastasis. Tumor markers have been used with some success to detect subclinical recurrences and could be used to target more invasive or expensive procedures. In chemotherapy, many newer agents are promising significantly improved survival, but again, the evidence for greater benefit when administered prior to the patient becoming symptomatic is lacking. Overall, it appears that follow-up policy is as much decided by the wealth and facilities of the institution as by any significant evidence base. Although the early detection of recurrent cancer is an emotive issue for both patients and surgeons, considering the amount of time and money invested in follow-up, and the lack of evidence of efficacy, a randomized controlled trial of intensive follow-up is required.

Postoperative anatomic and pathologic findings at CT following gastrectomy

Helical computed tomography (CT) is useful in identifying postoperative anatomic changes, complications, and tumor recurrence in gastric cancer patients who have undergone gastrectomy. Postoperative anatomic changes can usually be identified on consecutive CT scans. Complications include anastomotic leakage, duodenal stump leakage, intraabdominal bleeding, wound complications, and other less common complications (postoperative pancreatitis, retention of surgical foreign bodies, diffuse peritonitis). The degree and extent of bowel wall thickening is important in diagnosing tumor recurrence; however, CT lacks specificity. Large or conglomerated lymph node metastases can be easily diagnosed at CT; however, small solitary or focal metastases may not be detected or differentiated from nonmetastatic nodes. Ascites, a common finding with peritoneal seeding in gastrointestinal tumors, is well depicted at CT. Hematogenous metastases from gastric carcinoma are most frequently seen in the liver and are best demonstrated with helical CT performed during the portal venous phase of enhancement (sensitivity >90% for the detection of lesions >1 cm). The sophisticated surgical procedures used in gastrectomy can alter normal anatomy and make image interpretation difficult; thus, familiarity with the appearance of postoperative anatomic changes, complications, and tumor recurrence is essential for accurate CT evaluation of affected patients.

Failure to detect early recurrence of gastric cancer

Early gastric cancer recurrence is sometimes difficult to diagnose even by protocols using imaging techniques and tumor markers. We report a gastric cancer recurrence diagnosed by the appearance of a Sister Mary Joseph's nodule that illustrates the lack of sensitivity of these methods. We also discuss the protocol we currently follow for these patients.