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Addition of FDG-PET/CT and Staging Laparoscopy to the Initial Staging of Locally Advanced Gastric Cancer


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In a Dutch cohort study (PLASTIC) reported in JAMA Surgery, Gertsen et al found that staging laparoscopy provided more diagnostic information resulting in change of treatment intent than F-18 fluorodeoxyglucose positron-emission tomography/computed tomography (FDG-PET/CT) in patients with clinically curable locally advanced gastric cancer based on initial staging with gastroscopy and CT.

The multicenter prospective observational cohort study included 394 patients with locally advanced, clinically curable gastric adenocarcinoma (≥ cT3 and/or N+, M0 category based on CT). Patients underwent FDG-PET/CT and/or staging laparoscopy after initial staging. The primary outcome measure was the proportion of patients with changed intent of treatment based on findings with the two procedures. Outcomes were analyzed in the total population of 394 patients unless otherwise specified.

Key Findings

A total of 382 patients underwent FDG-PET/CT, 357 underwent staging laparoscopy, and 345 underwent both.

KEY POINTS

  • The combination of FDG-PET/CT and staging laparoscopy detected metastatic or unresectable disease in 78 (20%) of 394 patients.
  • Distant metastases in 12 patients (3%) were detected by FDG-PET/CT, staging laparoscopy detected peritoneal or locally nonresectable disease in 73 patients (19%), and metastases in 7 (2%) detected by both.
  • Actual change in treatment intent from curative to palliative resulted from detection of metastatic disease in all 12 cases (3%) by FDG-PET/CT and in 60 cases (15%) by staging laparoscopy.

The combination of FDG-PET/CT and staging laparoscopy detected metastatic or unresectable disease in 78 (20%) of 394 patients. Distant metastases in 12 patients (3%) were detected by FDG-PET/CT, staging laparoscopy detected peritoneal or locally unresectable disease in 73 patients (19%), and metastases in 7 (2%) detected by both. In theory, these findings should have prompted a change in treatment intent for all patients with these findings.  

Actual change in treatment intent from curative to palliative resulted from detection of metastatic disease in all 12 cases (3%) by FDG-PET/CT and in 60 cases (15%) by staging laparoscopy. Among the remaining 13 patients identified by staging laparoscopy, 3 did not undergo resection due to death during or shortly after neoadjuvant chemotherapy or progression of disease; the remaining 10 had limited peritoneal metastases (n = 3) or only positive cytologic test results (n = 7) and underwent perioperative chemotherapy or chemoradiotherapy and surgical resection.

FDG-PET/CT had a sensitivity of 33% and a specificity of 97% for detection of distant metastases. Staging laparoscopy had a sensitivity of 82% and a specificity of 78% for detection of macroscopic peritoneal metastases.

Secondary findings on FDG-PET/CT included clinically relevant lesions in 83 (22%) of 382 patients and led to additional examination in 65 (16%) of 394. A second primary cancer was confirmed in seven patients.

Staging laparoscopy resulted in complications requiring reintervention in three patients (0.8%), with no postoperative mortality being observed.

Among patients undergoing both FDG-PET/CT and staging laparoscopy, the mean diagnostic delay was 19 days when FDG-PET/CT was performed first and 18 days when staging laparoscopy was performed first. Mean delay was 17 days when either was performed alone.

The investigators concluded, “This study’s findings suggest an apparently limited additional value of FDG-PET/CT; however, staging laparoscopy added considerably to the staging process of locally advanced gastric cancer by detection of peritoneal and [unresectable] disease. Therefore, it may be useful to include staging laparoscopy in guidelines for staging advanced gastric cancer, but not FDG-PET/CT.”

Jelle P. Ruurda, MD, PhD, of the Department of Surgery, University Medical Center Utrecht, is the corresponding author for the JAMA Surgery article.

Disclosure: The study was supported by the government-funded Netherlands Organization for Health Research and Development. For full disclosures of the study authors, visit jamanetwork.com.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
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