PD-0006 the Prognostic Utility of Metabolic Information Provided by FDG Pet in the Evaluation of Solitary Colorectal Hepatic Metastases

Abstract

ABSTRACT IntroductionBackground Hepatic metastasis is the most common site of recurrence in colorectal cancer (CRC). Early detection and resection improve survival. There have been many attempts to establish a reliable pre-operative clinical scoring system for selecting suitable candidates for surgery. Recently positron emission tomography (PET) using the glucose analogue FDG has made a significant clinical impact in the assessment of these patients. FDG PET reduces futile hepatic resection by selecting more appropriate patients for surgery, and excluding patients with more extensive hepatic disease or extrahepatic metastases. Semi-quantitative measurements using standardized uptake value (SUV) evaluates the degree of metabolic activity of the metastasis, has also shown potential as a prognostic indicator. Methods Patient and Departmental PET data-bases were reviewed and those meeting the following criteria were included: (1) Patients with resected primary colorectal cancer, (2) first CRC recurrence in liver (3), solitary hepatic metastasis as reported on PET or PET/CT. Patients with extra-hepatic metastasis as reported on PET or PET/CT and patients who received neo-adjuvant chemotherapy or other forms of local hepatic therapy prior to PET are excluded. A total of 71 usable patient data was collected. SUV measurements, glycolytic tumor volumes and clinopathological data were collected. Overall survival (OS) and disease free survival (DFS) were used as outcomes and analysed using the Kaplan-Meier analysis. Results Five-year overall survival was 57.2%. OS was strongly associated with clinicopathological factors such as the interval between primary resection and PET scan with an interval 48mm and > 48mm respectively on PET (p > 0.03) and 66.1% and 25.4% for lesions C 60mm for surgical specimens (p 4.1 =26.7%, p = 0.039). Glycolytic volumes at SUV thresholds of 3 and 3.5 also demonstrated statistically significant differences in survival (cut-off volumes of 80cc and 150cc). Five-year overall disease free rate was 54.3%. Disease free interval was associated with the number of nodes examined in primary CRC (cut-off 17, less is better, p Conclusion We have found that PET had strong utility in predicting overall survival in patients with CRC and solitary hepatic metastasis. Metabolic information provided by PET in terms of SUV ratios and glycolytic volumes were prognostic and may be useful as an adjunct to clinicopathological factors in selecting patients for adjuvant chemotherapy or targeted therapy.