Sa1456 Omental Fine Needle Aspiration and Impact on Cancer Staging: A Novel Indication for Endoscopic Ultrasound

Abstract

BackgroundOmental thickening may occur in the setting of both malignant and benign processes. Omental metastasis may be difficult to detect with non-invasive imaging, but often affects cancer staging and resectability. Endoscopic ultrasound (EUS) may allow both detection and confirmation of omental metastasis by fine needle aspiration (FNA).AimsIn patients undergoing EUS FNA to evaluate omental thickening and possible metastasis, we determined: 1) the sensitivity and specificity of cytology in those patients with a gold-standard diagnosis, 2) the prevalence of omental thickening identified by CT and/or MRI; 3) whether EUS FNA findings resulted in tumor upstaging and change in resectability status for patients with malignancy, and 4) complication rates of omental EUS FNA.MethodsWe reviewed a prospectively maintained EUS database to identify all patients who underwent omental EUS FNA. Findings were compared to the gold standard diagnosis based on clinicopathologic findings and a minimum of 1 year of clinical follow-up for patients with benign disease. Cytological interpretations of malignant or suspicious for malignancy were deemed positive and all other interpretations were regarded as negative.ResultsBetween 10/2002 and 10/2010, 37 patients (mean age±SD: 62.2±15.4 y; 19 (51%) male), underwent omental FNA during EUS. A median of 3 passes (range 1-8) was obtained with adequate cellular yield in 36/37 (97%) cases. EUS was performed to evaluate malignancy in 34 patients; primary sites included pancreas (n=24), stomach (n=2), bile duct (n=5), rectum (n=1), gallbladder (n=2). The remaining 3 patients had benign disease. All patients underwent pre-EUS imaging with either CT (n=28), MRI (n=2), or both (n=7). Non-invasive imaging identified the omental thickening in only 7 (19%) of the 37 patients. Positive cytology was identified in 20/37 (54%) patients. Among patients with a gold-standard diagnosis (n=30), the sensitivity and specificity of EUS-FNA for omental metastasis were 95.5% and 100%, respectively. Positive omental cytology led to tumor upstaging in 11/20 (55%) patients and converted 8/20 (40%) from resectable to unresectable. The high rate for conversion to unresectability is likely due to our tendency to sample abnormal appearing omentum when the findings are expected to impact patient care. Procedure related complications (n=2; 5%) included pancreatitis and abdominal pain.ConclusionEUS detects omental metastasis that may be undetected with CT and/or MRI. Our data suggest that EUS FNA is both safe and effective for diagnosis of omental metastases and may also be used to help identify a benign process. The findings may impact tumor staging, resectability status and patient care. BackgroundOmental thickening may occur in the setting of both malignant and benign processes. Omental metastasis may be difficult to detect with non-invasive imaging, but often affects cancer staging and resectability. Endoscopic ultrasound (EUS) may allow both detection and confirmation of omental metastasis by fine needle aspiration (FNA). Omental thickening may occur in the setting of both malignant and benign processes. Omental metastasis may be difficult to detect with non-invasive imaging, but often affects cancer staging and resectability. Endoscopic ultrasound (EUS) may allow both detection and confirmation of omental metastasis by fine needle aspiration (FNA). AimsIn patients undergoing EUS FNA to evaluate omental thickening and possible metastasis, we determined: 1) the sensitivity and specificity of cytology in those patients with a gold-standard diagnosis, 2) the prevalence of omental thickening identified by CT and/or MRI; 3) whether EUS FNA findings resulted in tumor upstaging and change in resectability status for patients with malignancy, and 4) complication rates of omental EUS FNA. In patients undergoing EUS FNA to evaluate omental thickening and possible metastasis, we determined: 1) the sensitivity and specificity of cytology in those patients with a gold-standard diagnosis, 2) the prevalence of omental thickening identified by CT and/or MRI; 3) whether EUS FNA findings resulted in tumor upstaging and change in resectability status for patients with malignancy, and 4) complication rates of omental EUS FNA. MethodsWe reviewed a prospectively maintained EUS database to identify all patients who underwent omental EUS FNA. Findings were compared to the gold standard diagnosis based on clinicopathologic findings and a minimum of 1 year of clinical follow-up for patients with benign disease. Cytological interpretations of malignant or suspicious for malignancy were deemed positive and all other interpretations were regarded as negative. We reviewed a prospectively maintained EUS database to identify all patients who underwent omental EUS FNA. Findings were compared to the gold standard diagnosis based on clinicopathologic findings and a minimum of 1 year of clinical follow-up for patients with benign disease. Cytological interpretations of malignant or suspicious for malignancy were deemed positive and all other interpretations were regarded as negative. ResultsBetween 10/2002 and 10/2010, 37 patients (mean age±SD: 62.2±15.4 y; 19 (51%) male), underwent omental FNA during EUS. A median of 3 passes (range 1-8) was obtained with adequate cellular yield in 36/37 (97%) cases. EUS was performed to evaluate malignancy in 34 patients; primary sites included pancreas (n=24), stomach (n=2), bile duct (n=5), rectum (n=1), gallbladder (n=2). The remaining 3 patients had benign disease. All patients underwent pre-EUS imaging with either CT (n=28), MRI (n=2), or both (n=7). Non-invasive imaging identified the omental thickening in only 7 (19%) of the 37 patients. Positive cytology was identified in 20/37 (54%) patients. Among patients with a gold-standard diagnosis (n=30), the sensitivity and specificity of EUS-FNA for omental metastasis were 95.5% and 100%, respectively. Positive omental cytology led to tumor upstaging in 11/20 (55%) patients and converted 8/20 (40%) from resectable to unresectable. The high rate for conversion to unresectability is likely due to our tendency to sample abnormal appearing omentum when the findings are expected to impact patient care. Procedure related complications (n=2; 5%) included pancreatitis and abdominal pain. Between 10/2002 and 10/2010, 37 patients (mean age±SD: 62.2±15.4 y; 19 (51%) male), underwent omental FNA during EUS. A median of 3 passes (range 1-8) was obtained with adequate cellular yield in 36/37 (97%) cases. EUS was performed to evaluate malignancy in 34 patients; primary sites included pancreas (n=24), stomach (n=2), bile duct (n=5), rectum (n=1), gallbladder (n=2). The remaining 3 patients had benign disease. All patients underwent pre-EUS imaging with either CT (n=28), MRI (n=2), or both (n=7). Non-invasive imaging identified the omental thickening in only 7 (19%) of the 37 patients. Positive cytology was identified in 20/37 (54%) patients. Among patients with a gold-standard diagnosis (n=30), the sensitivity and specificity of EUS-FNA for omental metastasis were 95.5% and 100%, respectively. Positive omental cytology led to tumor upstaging in 11/20 (55%) patients and converted 8/20 (40%) from resectable to unresectable. The high rate for conversion to unresectability is likely due to our tendency to sample abnormal appearing omentum when the findings are expected to impact patient care. Procedure related complications (n=2; 5%) included pancreatitis and abdominal pain. ConclusionEUS detects omental metastasis that may be undetected with CT and/or MRI. Our data suggest that EUS FNA is both safe and effective for diagnosis of omental metastases and may also be used to help identify a benign process. The findings may impact tumor staging, resectability status and patient care. EUS detects omental metastasis that may be undetected with CT and/or MRI. Our data suggest that EUS FNA is both safe and effective for diagnosis of omental metastases and may also be used to help identify a benign process. The findings may impact tumor staging, resectability status and patient care.