Staging gastric cancer using pet/ct

Sara Zahmatkesh,1,* Mohammad hossein jamshidi,2

1. Department of Radiologic Technology, Faculty of Paramedicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
2. Department of Radiologic Technology, Faculty of Paramedicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Abstract

Introduction

Gastric cancer is the fifth most common cancer worldwide. there is a widely accepted consensus of the usefulness of fdg pet/ct in staging and restaging of gastric cancer. although some types of gastric cancer are not highly fdg avid and fdg pet/ct is not recommended by some authors and major guidelines such as esmo, there is a widely accepted consensus of the usefulness of fdg pet/ct in staging of gastric cancer. some authors even considered a promising role for fdg pet/ct in staging of primary gastric cancer.

Methods

Publications were retrieved by a systematic search of multiple bibliographic databases, including medline, embase, scopus, cochrane library, web of science, biomed central, science direct, and google scholar. the language of search was restricted to english.

Results

In a retrospective study comparing the roles of contrast-enhanced ct (ce-ct) and fdg pet/ct in detecting primary gastric cancer, respective sensitivity, specificity, negative predictive value (npv), positive predictive value (ppv), and accuracy values of 92%, 57%, 57%, 92%, and 87% and 82%, 86%, 46%, 97%, and 82% were calculated. fdg pet/ct was also significantly more specific for detecting both lymph nodes(95% vs. 62%) and distant metastases (89% vs. 63%).however, the detection of low-fdg-avid primary tumors and corresponding lymph node metastatic disease is a flaw of this technique. for instance, only 30%–40% of metastatic lymph nodes from non-fdg-avid primary tumors accumulate fdg, which is another factor for false-negative images.therefore, the use of fdg pet/ct in some special types of gastric cancer (i.e., signet cell carcinoma and mucinous carcinoma) should be designated only for special cases with unclear findings on other imaging modalities. in the assessment of solid organ metastases, fdg pet/ct showed an accuracy, sensitivity, and specificity of 97%, 95%, and 100%, respectively.

Conclusion

Mri and ce-ct may provide better sensitivity in the detection of small hepatic metastases and tiny peritoneal carcinomatosis, respectively. fdg pet/ct is also a promising surveillance method after surgery for detecting gastric cancer recurrence with an approximate sensitivity of 85% and specificity of 88%. in a meta-analysis of eight studies and 500 patients, the pooled sensitivity and specificity were 86% and 88% for this modality in the detection of recurrent gastric cancer. finally, fdg pet/ct is recommended for staging and restaging of gastric cancer and for evaluation after neoadjuvant therapy.

Keywords

Gastric cancer, pet/ct, staging.