One-year-experience in the use of Partial Volume Correction impact on the role of 18FDG PET for the diagnosis, prognosis and therapy monitoring toward personalized medicine in oncology

AIM: The identification of PET biomarkers able to characterize oncological diseases and to predict their response and outcome to therapy in vivo and non invasively is a challenging objective for a personalized medicine approach. To obtain accurate PET quantitative biomarkers from small oncological lesions, Partial Volume Correction (PVC) should be applied. This work presents results of one-yearexperience in the use of PVC for the measurement of SUV by means of 18FDG PET, showing the impact that PVC has on the diagnostic, prognostic and therapy monitoring value of SUV in different oncological pathologies. MATERIALS AND METHODS: In the Nuclear Medicine Departments of H San Raffaele Milan and H San Raffaele Giglio (Italy), a PVC method (Gallivanone et al., 2011) has been implemented 1 year ago and systematically used to obtain PVC-SUVBW from PET oncological studies (173): 1) 40 breast cancer pre-surgical 18FDG PET/CT studies were considered, to assess the value of PVC-SUVBW in revealing tumor biological characteristics; 2) 56 gastro-esophageal cancer pre-surgical 18FDG PET/CT studies, to understand the value of PVC-SUVBW in evaluating pathological characteristics; 3) 19 head and neck cancer basal and follow-up (before radiotherapy) 18FDG PET/CT studies, to evaluate the value of PVC-SUVBW in predicting radiotherapy outcome; 4) 29 bone metastasis (primitive breast carcinoma) basal and follow-up (after chemotherapy and hormone therapy) 18FDG PET/CT studies, to evaluate the value of PVC-SUVBW in defining metastasis response to treatment. RESULTS: A general effect of PVC was to increase SUVBW (>100% in very small lesions) and SUVBW cutoff values, and to increase the significance of statistical analysis. 18FDG PVC-SUVBW has been found: 1) a biomarker of cell proliferation in breast cancer being more significantly associated to the positivity of the MiB-1 proliferation index (p<0.001 with PVC vs p<0.03 without PVC); 2) a diagnostic biomarker in gastro-esophageal cancer (SUVBW without PVC was not), being significantly different in different cancer histological types (p<0.05) and in non infiltrating vs infiltrating pathologies (p<0.05); 3) a biomarker with prognostic value in HNC, being more significantly correlated with LRFS and DFS (p<0.025 and <0.010 with PVC vs p<0.05 and <0.025 without PVC); 4) noteworthy, the application of PVC changed the response of some lesions by means of PVC-SUVBW (in 15% for EORTC1999 and 12.5% for PERCIST). CONCLUSIONS: Our experience shows that PVC has a high impact on the 18FDG PET role in oncology, enhancing the value of SUVBW for the diagnosis, prognosis and therapy monitoring and response.