PT  - JOURNAL ARTICLE
AU  - Woff, Erwin
AU  - Salvatore, Lisa
AU  - Marmorino, Federica
AU  - Genovesi, Dario
AU  - Critchi, Gabriela
AU  - Guiot, Thomas
AU  - Ameye, Lieveke
AU  - Sclafani, Francesco
AU  - Hendlisz, Alain
AU  - Flamen, Patrick
TI  - Combined Metabolically Active Tumor Volume and Early Metabolic Response Improve Outcome Prediction in Metastatic Colorectal Cancer
AID  - 10.2967/jnumed.120.245357
DP  - 2021 Jul 01
TA  - Journal of Nuclear Medicine
PG  - jnumed.120.245357
4099  - http://jnm.snmjournals.org/content/early/2021/07/29/jnumed.120.245357.short
4100  - http://jnm.snmjournals.org/content/early/2021/07/29/jnumed.120.245357.full
AB  - Stratification of metastatic colorectal cancer (mCRC) patients is mostly based on clinical and biological characteristics. This study aimed to validate the prognostic value of 18F-FDG PET/CT-based biomarkers such as baseline whole-body metabolically active tumor volume (WB-MATV) and early metabolic response (mR) in mCRC. Methods: The development cohort included chemorefractory mCRC patients enrolled in two prospective Belgian multicenter trials evaluating last-line treatments (multikinase inhibitors). The validation cohort included mCRC patients from an Italian center treated with chemotherapy and bevacizumab as first-line. Baseline WB-MATV was defined as the sum of metabolically active volumes of all target lesions identified on the baseline 18F-FDG PET/CT. Early metabolic response (mR) assessment was performed following usual response criteria (PERCIST–30%, PERCIST–15%, EORTC) and the so-called CONSIST method, which defines response as a decrease of SULmax ≥ 15% for all target lesions. Baseline WB-MATV and early mR assessment were investigated along with usual clinical factors and correlated with overall and progression-free survival (OS/PFS). Results: Clinical factors, baseline WB-MATV and early mR were evaluable in 192/239 and 94/125 patients of the development and validation cohorts, respectively. Except for PERCIST–30%, all response methods were equivalent in terms of outcome prediction and CONSIST was found to be the most accurate. Baseline WB-MATV and early mR using CONSIST method were independent prognostic parameters after adjustment for clinical factors in the development and validation sets for both OS (HR WB-MATV: 1.87 (1.17-2.97), P = 0.005, and HR early mR: 1.79 (1.08-2.95), P = 0.02 for the validation set), and PFS (HR WB-MATV: 1.94 (1.27-2.97), P = 0.002, and HR early mR: 1.69 (1.04-2.73), P = 0.03 for the validation set). Conclusion: Baseline WB-MATV and early mR are strong independent prognostic biomarkers for OS/PFS in mCRC, regardless of treatment received. Therefore, combining these biomarkers improves risk stratification for OS/PFS in mCRC.