Automated Definition of Skeletal Disease Burden in Metastatic Prostate Carcinoma: A 3D Analysis of SPECT/CT Images

Abstract

To meet the current need for skeletal tumor-load estimation in castration-resistant prostate cancer (CRPC), we developed a novel approach based on adaptive bone segmentation. In this study, we compared the program output with existing estimates and with the radiological outcome. Seventy-six whole-body single-photon emission computed tomographies/x-ray computed tomography with 3,3-diphosphono-1,2-propanedicarboxylic acid from mCRPC patients were analyzed. The software identified the whole skeletal volume (SVol) and classified the voxels metastases (MVol) or normal bone (BVol). SVol was compared with the estimation of a commercial software. MVol was compared with manual assessment and with prostate specific antigen (PSA) levels. Counts/voxel were extracted from MVol and BVol. After six cycles of 223RaCl2-therapy every patient was re-evaluated as having progressive disease (PD), stable disease (SD), or a partial response (PR). SVol correlated with that of the commercial software (R = 0,99, p < 0,001). MVol correlated with the manually-counted lesions (R = 0.61, p < 0.001) and PSA (R = 0,46, p < 0.01). PD had a lower counts/voxel in MVol than PR/SD (715 ± 190 vs. 975 ± 215 and 1058 ± 255, p < 0.05 and p < 0.01) and BVol (PD 275 ± 60, PR 515 ± 188 and SD 528 ± 162 counts/voxel, p < 0.001). Segmentation-based tumor load correlated with radiological/laboratory indices. Uptake was linked with the clinical outcome, suggesting that metastases in PD patients have a lower affinity for bone-seeking radionuclides and might benefit less from bone-targeted radioisotope therapies.

What Is the Role of Imaging in Cancers?

“…Table 1 shows a summary of the topics and the papers included for each topic [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ]. The majority of papers are focused on prostate cancer (PCa) and radiomics.…”

“…Bauckneht et al [ 19 ] support the role of 18F-Fluorodeoxyglucose (FDG) PET/CT as a tool for patient selection and response assessment in metastatic castrate resistant PCa patients undergoing 223Ra administration. Furthermore, in this latter setting of patients, a segmentation-based tumor load at 99mTc-dysphonate SPECT/CT was linked with clinical outcome [ 21 ]. Finally, a radiomic approach with a specific magnetic resonance imaging (MRI) protocol can be useful to appropriately detect and characterize PCa [ 31 ].…”