PET for staging esophageal cancer – pro
Esophageal cancer is currenlty staged with CT, endoscopic ultrasound (EUS) and endoscopy. What would PET scanning add to staging accuracy? There is convincing data that PET significantly improves the detection of distant lymph node and organ metastases (stage IV). In the United States, most patients present with the symptoms of dysphagia and weight loss, indicating the presence of advanced locoregional disease, usually stage IIB or III. One treatment option for these patients is to undertake aggressive multimodality therapy, including esophagectomy. This is not appropriate for patients with stage IV disease, and PET should be useful in this situation to help exclude patients with stage IV disease from this type of management.
Because current PET scans can produce false-negative results, PET cannot replace CT of the chest and abdomen at this point. It is also potentially misleading to follow-up the results of chemotherapy. PET can also produce false positive findings, and biopsy, cytology, or at least radiologic confirmation of positive areas on PET scans should be obtained if possible. The problem for all imaging modalities is detecting very small foci of cancer in lymph nodes or other distant sites and in differentiating enlarged lymph nodes that are reactive or inflammatory from those replaced by metastatic disease.
PET scan also cannot replace EUS staging for depth of tumor invasion. EUS is increasingly available in the United States, and new thinner EUS probes, some wire-guided, can traverse almost any malignant stricture to stage the entire tumor. It has been reported that surgical management alone offers little benefit if EUS shows invasion of adjacent structures or organs (T4).
A recent review concluded that PET cannot “replace either CT or EUS, but PET has clearly emerged as another useful test for esophageal cancer staging.”
Iyer RB, Silverman PM, Tamm EP, Dunnington JS, DuBrow RA. Diagnosis, staging, and follow-up of esophageal cancer. AJR Am J Roentgenol. 2003 Sep;181(3):785-93.
Skehan SJ, Brown AL, Thompson M, Young JE, Coates G, Nahmias C. Imaging features of primary and recurrent esophageal cancer at FDG PET. Radiographics. 2000 May-Jun;20(3):713-23.
Flamen P, Van Cutsem E, Lerut A, Cambier JP, Haustermans K, Bormans G, De Leyn P, Van Raemdonck D, De Wever W, Ectors N, Maes A, Mortelmans L. Positron emission tomography for assessment of the response to induction radiochemotherapy in locally advanced oesophageal cancer. Ann Oncol. 2002 Mar;13(3):361-8.
Charles J. Lightdale, MD Positron Emission Tomography: Another Useful Test for Staging Esophageal Cancer Journal of Clinical Oncology, Vol 18, Issue 18 (September), 2000: 3199-3201