Hepatocellular carcinoma (HCC) is the fifth most common cancer and the third most common cause of cancer-related death worldwide. Orthotopic liver transplantation (OLT) and resection are curative treatment options for well-selected patients with HCC, whereas loco-ablative therapy has been shown to prolong survival. Organ and treatment allocations for these patients are currently based on the number and size of tumors, as defined by the Milan criteria, and on functional capacity, and they are incorporated into the Barcelona Clinic Liver Cancer staging system and treatment strategy. Even though these staging criteria have markedly improved the outcomes of patients with HCC, they still lack accuracy in predicting the risk of tumor recurrence because they do not incorporate markers of tumor biology and behavior. Positron emission tomography (PET) and computed tomography (CT) with Hepatocellular carcinoma (HCC) is the fifth most common cancer and the third most common cause of cancer-related death worldwide. 1 Orthotopic liver transplantation (OLT) is a curative treatment option for patients with HCC who meet strict criteria. Initial success with OLT was hampered by poor survival

562 Background: Current staging of patients (pts) with pathological stage III colon cancer is suboptimal; many pts still recur despite unremarkable preoperative staging work-up. We previously reported that early postoperative PET-CT can alter the stage and management of pts with high risk stage III colon cancer in up to 19% of patients. The aim of the current study was to expand the previous one to a larger cohort and to determine the role of early postoperative PET-CT in the general population of stage III colon cancer pts, regardless of their individual risk. Methods: A retrospective chart review of all consecutive pts with stage III colon cancer who underwent early postoperative PET-CT between 2007 and 2016. Demographic and clinicopathological data were collected. Results: 247 pts, 124 (50%) males, with a median age of 66 years (range, 30-92), were included. Pathological stage was IIIA, IIIB and IIIC in 18 (7.3%), 161 (65.1%) and 72 (29.1%) pts, respectively. The median number of lymph nodes retrieved was 15 (range, 6-64) and that of positive lymph nodes was 2 (range, 0-21). High FDG-uptake was observed in 52 (21.0%) pts, including 6 (2.4%) who had clear postoperative changes, 10 (4.0%) who had a false positive abnormal uptake of whom 6 underwent invasive diagnostic procedures. The PET-CT results modified the management of 36 pts (14.5%) who were found to have true positive findings: 30 (12.1%) were proven to have overt metastatic disease and in 6 (2.4%) a second primary was discovered. With the median follow-up of 39.0 months (range 7.2-98.4 months), of the 30 pts found to be metastatic, 10 (33.3%) underwent curative treatments and are currently with no evidence of disease (NED). Updated data, on more patients and a longer follow-up, will be presented at the meeting. Conclusions: Early postoperative PET-CT changed the staging and treatment of 14.5% of resected stage III pts, and has the potential for early detection of curable metastatic disease. We currently evaluate this strategy and its actual impact in a prospective trial.

566 Background: Routine PET-CT evaluation is still not indicated for stage III CRC patients; however accumulating data suggest that it may modify these patients' staging and treatment. We hence evaluated the role of PET-CT in high risk stage III CRC patients and to characterize positive predictors. Methods: Retrospective chart review of stage III CRC patients who underwent PET-CT for being at high risk for systemic disease attributable to: early T stage (T < 3), grade > 3, < 12 lymph-nodes examined, > 3 involved lymph-nodes, elevated postoperative CEA and/or CA-19.9. The demographic and clinicopathological characteristics of patients found to have metastatic disease were compared to those who were negative. Results: Seventy-three patients (33 males [45%], median age 67 years [range: 29-88 years]) were included. Pathologic FDG-uptake was observed in 33 (45%) patients. Of them, 16 (22%) were upstaged with altered treatment protocol, 13 (18%) required further work-up and 4 (5%) were found to have post operative changes. Elevated post-operative CEA and CA-19.9 levels correlated with positive PET-CT (p = 0.002 and p = 0.015, respectively). None of the other examined parameters differed between the groups. With a median follow-up of 26 months (range:1-63 months), overall survival was 88% in patients with positive PET-CT and 92% in patients with negative PET-CT. Eight patients in the positive group were disease free following metastectomy, five were alive with disease, two patients died of disease and one patient died of other cause. Conclusions: Selective postoperative PET-CT influenced staging/therapy in 22% of high risk stage III CRC patients. Postoperative CEA and CA-19.9 levels may play a role in selecting eligible patients. Failure to identify other parameters may be related to the preexisting selection bias and the small cohort. No significant financial relationships to disclose.

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