ABSTRACT
PURPOSE: This prospective study aimed (1) to assess the non-small cell lung cancer (NSCLC) evolutive patterns to immunotherapy using FDG-PET and (2) to describe their association with clinical outcome. DESIGN: Fifty patients with metastatic NSCLC were included before pembrolizumab or nivolumab initiation. FDG-PET scan was performed at baseline and after 7 weeks of treatment (PETinterim1) and different criteria/parameters of tumor response were assessed, including PET response criteria in solid tumors (PERCIST). If a first PERCIST progressive disease (PD) without clinical worsening was observed, treatment was continued and a subsequent FDG-PET (PETinterim2) was performed at 3 months of treatment. Pseudo-progression (PsPD) was defined as a PERCIST response/stability on PETinterim2 after an initial PD. If a second PERCIST PD was assessed on PETinterim2, a homogeneous progression of lesions (termed immune homogeneous progressive-disease: iPDhomogeneous) was distinguished from a heterogeneous evolution (termed immune dissociated-response: iDR). A durable clinical benefit (DCB) of immunotherapy was defined as treatment continuation over a 6-month period. The association between PET evolutive profiles and DCB was assessed. RESULTS: Using PERCIST on PETinterim1, 42% (21/50) of patients showed a response or stable disease, most of them (18/21) reached a DCB. In contrast, 58% (29/50) showed a PD, but more than one-third (11/29) were misclassified as they finally reached a DCB. No standard PETinterim1 criteria could accurately distinguished responding from non-responding patients. Treatment was continued in 19/29 of patients with a first PERCIST PD; the subsequent PETinterim2 demonstrated iPDhomogeneous, iDR and PsPD in 42% (8/19), 26% (5/19), and 32% (6/19), respectively. Whereas no patients with iPDhomogeneous experienced a DCB, all patients with iDR and PsPD reached a clinical benefit to immunotherapy. CONCLUSION: In patients with a first PD on PERCIST and treatment continuation, a subsequent PET identifies more than half of them with iDR and PsPD, both patterns being strongly associated with a clinical benefit of immunotherapy.
Subject(s)
Carcinoma, Non-Small-Cell Lung , Lung Neoplasms , Carcinoma, Non-Small-Cell Lung/diagnostic imaging , Carcinoma, Non-Small-Cell Lung/therapy , Fluorodeoxyglucose F18 , Humans , Immunotherapy , Lung Neoplasms/diagnostic imaging , Lung Neoplasms/therapy , Positron Emission Tomography Computed Tomography , Positron-Emission Tomography , Prospective Studies , Treatment OutcomeABSTRACT
18F-FDOPA PET has been historically used for the evaluation of parkinsonian syndromes in research settings. With the wider availability of PET cameras and 18F-DOPA this method can be used as a clinical diagnostic tool. Current acquisition protocols are simple with a 10 minute static acquisition performed 90 minutes post injection. Criteria for precise visual analysis of the images are defined. The performances of the method are reviewed throughout the literature. The method is very sensitive for detection of IPD versus normal patients. Few studies comparing 18F-FDOPA PET and DAT SPECT did not show any difference in diagnostic accuracy. 18F-FDOPA PET is reliable for evaluation of IPD progression. In general, atypical Parkinson's syndromes cannot be reliably differentiated from IPD since they share a similar nigro-striatal degeneration process. However, some patterns such as the asymmetrical faint homogeneous striatal uptake reduction pattern of CBD can be recognized. The short acquisition protocol, the various indications in oncology of 18F-FDOPA and the high quality of PET images are in favor of this technique in daily clinical practice for the improvement of diagnosis of parkinsonian syndromes.
Subject(s)
Dihydroxyphenylalanine/analogs & derivatives , Parkinsonian Disorders/diagnostic imaging , Parkinsonian Disorders/diagnosis , Positron-Emission Tomography/methods , Radiopharmaceuticals , Brain/diagnostic imaging , Disease Progression , Humans , Image Processing, Computer-Assisted , Reproducibility of Results , Sensitivity and Specificity , Time FactorsABSTRACT
AIM: We assessed in this study the influence of contrast-enhanced CT (ceCT) on PET/CT interpretation and PET/CT on ceCT interpretation in patients with lymphoma, before and after chemotherapy. METHODS: Fifty patients with Hodgkin disease (N.=17) or non-Hodgkin lymphomas (N.=33) were assessed before and after chemotherapy. PET/CT were performed 60 minutes after injection of FDG. Iopamidol was then injected and followed, 50 seconds later, by another CT. PET images were successively reconstructed using non-enhanced CT (PET-) and ceCT (PET+). Four nuclear physicians rated PET- and PET+ in random order. Three radiologists initially rated ceCT alone and then ceCT along with PET+. RESULTS: Before chemotherapy, global agreement (GA) was 99% (k=0.96) when PET- was compared to PET+. Nine (5%) lesions were discordant, 5 according to PET- and 4 to PET+. After chemotherapy, GA was 99% (k=0.91). Eight (15%) lesions were discordant, 3 according to PET- and 5 to PET+. Before chemotherapy, GA was 97% (k=0.91) when ceCT was compared to ceCT with PET+. Twenty-one (12%) lesions were discordant, 16 when ceCT were analyzed alone and 5 when ceCT was analyzed with PET+. After chemotherapy, GA was 95% (k=0.76). All 30 (35%) discordant lesions were positive according to ceCT alone. A significant difference between the 2 procedures was found in the pelvis and in the groin (P<0.05). CONCLUSION: PET+ did not differ from PET-, before and after chemotherapy. Fewer abnormalities were observed, when ceCT was analyzed with PET+, particularly after chemotherapy, due to residual masses that are better analyzed with functional imaging.
