18FDG PET Assessment of Therapeutic Response in Patients with Advanced or Metastatic Melanoma Treated with First-Line Immune Checkpoint Inhibitors.

BACKGROUND: Immune checkpoint inhibitors (ICI) are currently the first-line treatment for patients with metastatic melanoma. We investigated the value of positron emission tomography (PET) response criteria to assess the therapeutic response to first-line ICI in this clinical context and explore the potential contribution of total tumor metabolic volume (TMTV) analysis. METHODS: We conducted a retrospective study in patients treated with first-line ICI for advanced or metastatic melanoma, with 18F-FDG PET/CT performed at baseline and 3 months after starting treatment. Patients' metabolic response was classified according to PERCIST5 and imPERCIST 5 criteria. TMTV was recorded for each examination. RESULTS: Twenty-nine patients were included. The median overall survival (OS) was 51.2 months (IQR 13.6-not reached), and the OS rate at 2 years was 58.6%. Patients classified as responders (complete and partial response) had a 90.9% 2-year OS rate versus 38.9% for non-responders (stable disease and progressive disease) (p = 0.03), for PERCIST5 and imPERCIST 5 criteria. The median change in metabolic volume was 9.8% (IQR -59-+140%). No significant correlation between OS and changes in TMTV was found. CONCLUSION: The evaluation of response to immunotherapy using metabolic imaging with PERCIST5 and imPERCIST5 was significantly associated with OS in patients with advanced or metastatic melanoma.

Translating Molecules into Imaging-The Development of New PET Tracers for Patients with Melanoma.

Melanoma is a deadly disease that often exhibits relentless progression and can have both early and late metastases. Recent advances in immunotherapy and targeted therapy have dramatically increased patient survival for patients with melanoma. Similar advances in molecular targeted PET imaging can identify molecular pathways that promote disease progression and therefore offer physiological information. Thus, they can be used to assess prognosis, tumor heterogeneity, and identify instances of treatment failure. Numerous agents tested preclinically and clinically demonstrate promising results with high tumor-to-background ratios in both primary and metastatic melanoma tumors. Here, we detail the development and testing of multiple molecular targeted PET-imaging agents, including agents for general oncological imaging and those specifically for PET imaging of melanoma. Of the numerous radiopharmaceuticals evaluated for this purpose, several have made it to clinical trials and showed promising results. Ultimately, these agents may become the standard of care for melanoma imaging if they are able to demonstrate micrometastatic disease and thus provide more accurate information for staging. Furthermore, these agents provide a more accurate way to monitor response to therapy. Patients will be able to receive treatment based on tumor uptake characteristics and may be able to be treated earlier for lesions that with traditional imaging would be subclinical, overall leading to improved outcomes for patients.

Yield of FDG PET/CT for Defining the Extent of Disease in Patients with Kaposi Sarcoma.

BACKGROUND: Positron emission tomography/computed tomography with fluorodeoxyglucose (F-18) (FDG PET/CT) is increasingly used in Kaposi sarcoma (KS), but its value has not been assessed. OBJECTIVES: In this study, we aimed to evaluate the diagnostic accuracy of FDG PET/CT to define the extent of disease in KS. METHODS: Consecutive patients with KS referred to our department for FDG PET/CT were included. The diagnostic accuracy of FDG PET/CT for cutaneous and extra-cutaneous KS staging was assessed on a per lesion basis compared to staging obtained from clinical examination, standard imaging, endoscopy, histological analyses, and follow-up. RESULTS: From 2007 to 2017, 75 patients with FDG PET/CT were analyzed. The sensitivity and specificity of FDG PET/CT for the overall detection of KS lesions were 71 and 98%, respectively. Sensitivity and specificity were 100 and 85% for lymph nodes, 87 and 98% for bone, 87 and 100% for lungs, and 100 and 100% for muscle involvement, whereas sensitivity was only 17% to detect KS digestive involvement. The sensitivity of the diagnostic for KS cutaneous involvement increased from 73 to 88% when using a whole-body examination. CONCLUSION: FDG PET/CT showed good sensitivity and specificity for KS staging (digestive involvement excepted) and could be used for staging patients with active KS.

First Extensive Analysis of 18F-Labeled Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography in a Large Cohort of Patients With HIV-Associated Hodgkin Lymphoma: Baseline Total Metabolic Tumor Volume Affects Prognosis.

PURPOSE: 18F-labeled fluorodeoxyglucose positron emission tomography with computed tomography (18F-FDG PET-CT) data in HIV-associated Hodgkin lymphoma (HIV-HL) are scarcely reported. In addition to the description of the characteristics of both baseline and interim 18F-FDG PET-CT examinations (PET1 and iPET, respectively), the aim of this study was to assess the prognostic value of PET1 and previously identified clinical parameters in this population. PATIENTS AND METHODS: PET1 of 109 patients with HIV-HL, treated with doxorubicin, bleomycin, vinblastine, and dacarbazine chemotherapy regimen since 2007, and 104 iPET were centrally reviewed. All the patients were enrolled in an ongoing prospective single-center cohort of HIV-associated lymphoma. RESULTS: Most patients had a disseminated disease according to the Ann Arbor classification (30% stage III and 43% stage IV), with especially bone marrow and liver as extranodal localizations. After a median follow-up of 6.7 years, 12 patients relapsed (11%) and 13 died (12%). Five-year progression-free survival (PFS) was 75.1%, and 5-year overall survival was 86.1%. Median total metabolic tumor volume (TMTV) was 121.4 cm3. The optimal TMTV cutoff identified for prognostic analysis was 527 cm3, with a 2-year PFS of 71% in the 20 patients with TMTV > 527 cm3, compared with 91% in the 89 patients with TMTV ≤ 527 cm3 (P = .004). On multivariate analysis, a high TMTV was the only parameter independently associated with PFS. CONCLUSION: In this large series of HIV-HL patients with a homogeneous management, high TMTV on PET1 examination was associated with a poor prognosis.

Predictive factors of early progression after CAR T-cell therapy in relapsed/refractory diffuse large B-cell lymphoma.

Chimeric antigen receptor (CAR) T-cell therapy has emerged as an option for relapsed/refractory aggressive B-cell lymphomas that have failed 2 lines of therapy. Failures usually occur early after infusion. The purpose of our study was to identify factors that may predict failure, particularly early progression (EP), within the first month after infusion. Characteristics of 116 patients were analyzed at the time of decision (TD) to use commercial CAR (axicabtagene ciloleucel, n = 49; tisagenlecleucel n = 67) and at the time of treatment (TT), together with total metabolic tumor volume (TMTV) at TT. With a median follow-up of 8.2 months, 55 patients failed treatment; 27 (49%) were early progressors. The estimated 12-month progression-free survival (PFS) and overall survival (OS) were 47.2% (95% confidence interval [CI], 38.0-58.6) and 67.0% (95% CI, 57-79), respectively. Univariate analyses for PFS and OS identified Eastern Cooperative Oncology Group Performance Status (ECOG PS) ≥2, stage III/IV disease, extranodal (EN) sites ≥2, elevated lactate dehydrogenase (LDH), increased C-reactive protein (CRP), high International Prognostic Index at TD and at TT, as well as increased CRP, bulky mass, and high TMTV at TT, as risk factors. Multivariate analyses for PFS, EP, and OS identified elevated LDH and EN sites ≥2 at TD and the same predictors at TT (ie, increased CRP, EN sites ≥2, and TMTV >80 mL). In summary, risk factors identified for early progression at TD and at TT were EN involvement (≥2 sites) and lymphoma burden (LDH, TMTV).

Intermittent Versus Continuous Dosing of MAPK Inhibitors in the Treatment of BRAF-Mutated Melanoma.

The development of BRAF and MEK inhibitors (BRAFi/MEKi) has led to major advances in melanoma treatment. However, the emergence of resistance mechanisms limits the benefit duration and a complete response occurs in less than 20% of patients receiving BRAFi ± MEKi. In this study, we evaluated the impact of an intermittent versus continuous dosing schedule of BRAF/MEK inhibition in a melanoma model mildly sensitive to a BRAF inhibitor. The combination of a BRAFi with three different MEKi was studied with a continuous or intermittent dosing schedule in vivo, in a xenografted melanoma model and ex vivo using histoculture drug response assays (HDRAs) of patient-derived xenografts (PDX). To further understand the underlying molecular mechanisms of therapeutic efficacy, a biomarker pharmacodynamic readout was evaluated. An equal impact on tumor growth was observed in monotherapy or bitherapy regimens whether we used continuous and intermittent dosing schedules, with no significant differences in biomarkers expression between the treatments. The antitumoral effect was mostly due to modulations of expression of cell cycle and apoptotic mediators. Moreover, ex vivo studies did not show significant differences between the dosing schedules. In this context, our preclinical and pharmacodynamic results converged to show the similarity between intermittent and continuous treatments with either BRAFi or MEKi alone or with the combination of both.

18FDG-PET/CT and molecular markers to predict response to neoadjuvant chemotherapy and outcome in HER2-negative advanced luminal breast cancers patients.

BACKGROUND: The efficacy of neoadjuvant chemotherapy regimens in advanced luminal breast cancer patients is difficult to predict. Intrinsic properties of breast tumors, including altered gene expression profile and dynamic evaluation of metabolic properties of tumor cells using positron emission tomography/computed tomography (PET/CT) of tumor cells, have been identified to guide patient's prognosis. The aim of this study is to determine if both analyses may improve the prediction of response to neoadjuvant chemotherapy in ER-positive / HER2-negative breast cancers (BCs) patients. METHODS: We used metabolic PET parameters, at diagnosis and after two cycles of chemotherapy and proliferation gene expression profile on biopsy at diagnosis, in particular, the genomic grade index (GGI) analyzed by reverse transcription and quantitative polymerase chain reaction (RT-qPCR). The pathological response was the surrogate endpoint. RESULTS: The change of FDG uptake between baseline PET and interim PET after 2 cycles of neoadjuvant chemotherapy (ΔSUVmax) was highly associated with pCR (p=0.008). We also observed an ability of P53 mutated status (p=0.042), in addition to histological grade (p=0. 0004), and PR expression (p=0.01) to predict pCR in ER-positive BCs, whereas no proliferation marker predicted pCR (P=0.39 for GGI). Finally, only ΔSUVmax was significantly associated with event free survival (p=0.047). CONCLUSIONS: Our results confirm the predictive and prognostic value of tumor ΔSUVmax in ER-positive /HER2-negative advanced BCs patients. These findings can be helpful to select high-risk patients within trials investigating novel treatment strategies.

Assessing Bone Marrow Activity in Patients with Myelofibrosis: Results of a Pilot Study of 18F-FLT PET.

An emerging noninvasive approach to assess tissue proliferation uses the PET tracer 3'-deoxy-3'-18F-fluorothymidine (18F-FLT). To evaluate the diagnostic value of this technique in myelofibrosis, 18F-FLT PET imaging results were compared with bone marrow histology and bone marrow scintigraphy (BMS), the gold standard techniques in this clinical situation. Methods: Fifteen patients with histology-proven myelofibrosis were included consecutively in the study. Tracers' distributions were assessed using a visual grading assessment score of the uptake in the axial skeleton, proximal and distal limbs, liver, and spleen. This visual score was used to define patterns of tracer distribution and to compare the information provided either by PET or by BMS. A semiquantitative analysis with determination of SUVmax in the same localizations was performed for 18F-FLT PET. Results: The histology grade of fibrosis correlated with the SUVmax in the axial skeleton (spine and iliac crests) and proximal limbs. 18F-FLT uptake in these areas was much lower in patients with grade 3 fibrosis than in patients with grade 1 or 2 fibrosis. 18F-FLT PET showed the same distribution of uptake as BMS in 13 of 14 patients (1 patient did not undergo BMS). In 1 patient, 18F-FLT PET clearly showed an intense abnormal splenic uptake, whereas spleen uptake was inconclusive with BMS. Conclusion:18F-FLT PET appears to be a reliable and convenient technique to assess hematopoietic activity in bone marrow. It yields results close to those observed with BMS. In our study population, 18F-FLT uptake in the axial skeleton and proximal limbs assessed by SUVmax correlated with the grade of fibrosis. Thus, 18F-FLT PET may be a useful tool to measure the severity of myelofibrosis, and to monitor noninvasively the patients' status during follow-up. Finally, 18F-FLT PET may be foreseen as an alternative to BMS.

Correlation between tumour characteristics, SUV measurements, metabolic tumour volume, TLG and textural features assessed with 18F-FDG PET in a large cohort of oestrogen receptor-positive breast cancer patients.

PURPOSE: The study was designed to evaluate 1) the relationship between PET image textural features (TFs) and SUVs, metabolic tumour volume (MTV), total lesion glycolysis (TLG) and tumour characteristics in a large prospective and homogenous cohort of oestrogen receptor-positive (ER+) breast cancer (BC) patients, and 2) the capability of those parameters to predict response to neoadjuvant chemotherapy (NAC). METHODS: 171 consecutive patients with large or locally advanced ER+ BC without distant metastases underwent an 18F-FDG PET examination before NAC. The primary tumour was delineated with an adaptive threshold segmentation method. Parameters of volume, intensity and texture (entropy, homogeneity, contrast and energy) were measured and compared with tumour characteristics determined on pre-treatment breast biopsy (Wilcoxon rank-sum test). The correlation between PET-derived parameters was determined using Spearman's coefficient. The relationship between PET features and pathological findings was determined using the Wilcoxon rank-sum test. RESULTS: Spearman's coefficients between SUVmax and TFs were 0.43, 0.24, -0.43 and -0.15 respectively for entropy, homogeneity, energy and contrast; they were higher between MTV and TFs: 0.99, 0.86, -0.99 and -0.87. All TFs showed a significant association with the histological type (IDC vs. ILC; 0.02 < P < 0.03) but didn't with immunohistochemical characteristics. SUVmax and TLG predicted the pathological response (P = 0.0021 and P = 0.02 respectively); TFs didn't (P: 0.27, 0.19, 0.94, 0.19 respectively for entropy, homogeneity, energy and contrast). CONCLUSIONS: The correlation of TFs was poor with SUV parameters and high with MTV. TFs showed a significant association with the histological type. Finally, while SUVmax and TLG were able to predict response to NAC, TFs failed.

18FDG-PET/CT for predicting the outcome in ER+/HER2- breast cancer patients: comparison of clinicopathological parameters and PET image-derived indices including tumor texture analysis.

BACKGROUND: This study investigated the value of some clinicopathological parameters and 18 F-fluorodeoxyglucose-positron emission tomography/computed tomography (18FDG-PET/CT) indices, including textural features, to predict event-free survival (EFS) in estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER+/HER2-) locally advanced breast cancer (BC) patients. METHODS: FDG-PET/CT indices and clinicopathological parameters were assessed before neoadjuvant chemotherapy (NAC). After completion of chemotherapy, all patients had breast surgery with axillary lymph node dissection, followed by radiation therapy and endocrine therapy for 5 years. EFS was estimated using the Kaplan-Meier method. A Cox proportional hazard regression model was used for multivariate analysis. RESULTS: One hundred forty-three consecutive patients with stage II-III ER+/HER2- BC and without distant metastases at baseline PET were included. High standardized uptake values (SUVs), were associated with shorter EFS (HR = 3.51, P < 0.01 for SUVmax; HR = 2.76, P = 0.02 for SUVmean; and HR = 4.40 P < 0.01 for SUVpeak). Metabolically active tumor volume (MATV, HR = 3.47, P < 0.01) and total lesion glycolysis (TLG, HR = 3.10, P < 0.01) were also predictive of EFS. Homogeneity was not predictive (HR = 2.27, P = 0.07) and entropy had weak prediction (HR = 2.89, P = 0.02). Among clinicopathological parameters, EFS was shorter in progesterone receptor (PR)-negative tumor (vs. PR-positive tumor; HR = 3.25, P < 0.01); histology was predictive of EFS (lobular vs. ductal invasive carcinoma; HR = 3.74, P = 0.01) but not tumor grade (grade 3 vs. grade 1-2; HR = 1.64, P = 0.32). Pathological complete response after NAC was not correlated to the risk of relapse. Three parameters remained significantly associated with EFS in multivariate analysis. MATV (HR = 1.01, P < 0.01), progesterone receptor expression (HR = 2.90, P = 0.03) and tumor histology (HR = 3.80, P = 0.02). CONCLUSIONS: Baseline PET parameters measured before neoadjuvant treatment have prognostic values in ER+/HER2- locally advanced breast cancer patients. After multivariate analysis, metabolically active tumor volume remains significant while textural analysis of PET images is not of added value. Considering histopathological parameters, our study shows that patients with PR-negative or lobular invasive tumor have poorer prognosis than patients with PR-positive or ductal carcinoma, respectively.

[18F]MEL050 as a melanin-targeted PET tracer: Fully automated radiosynthesis and comparison to 18F-FDG for the detection of pigmented melanoma in mice primary subcutaneous tumors and pulmonary metastases.

INTRODUCTION: Melanoma is a highly malignant cutaneous tumor of melanin-producing cells. MEL050 is a synthetic benzamide-derived molecule that specifically binds to melanin with high affinity. Our aim was to implement a fully automated radiosynthesis of [18F]MEL050, using for the first time, the AllInOne™ synthesis module (Trasis), and to evaluate the potential of [18F]MEL050 for the detection of pigmented melanoma in mice primary subcutaneous tumors and pulmonary metastases, and to compare it with that of [18F]FDG. METHODS: Automated radiosynthesis of [18F]MEL050, including HPLC purification and formulation, were performed on an AllInOne™ synthesis module. [18F]MEL050 was synthesized using a one-step bromine-for-fluorine nucleophilic heteroaromatic substitution. Melanoma models were induced by subcutaneous (primary tumor) or intravenous (pulmonary metastases) injection of B16-F10-luc2 cells in NMRI mice. The maximum percentage of [18F]MEL050 Injected Dose per g of lung tissue (%ID/g Max) was determined on PET images, compared to [18F]FDG and correlated to in vivo bioluminescence imaging. RESULTS: The automated radiosynthesis of [18F]MEL050 required an overall radiosynthesis time of 48min, with a yield of 13-18% (not-decay corrected) and radiochemical purity higher than 99%. [18F]MEL050 PET/CT images were concordant with bioluminescence imaging, showing increased radiotracer uptake in all primary subcutaneous tumors and pulmonary metastases of mice. PET quantification of radiotracers uptake in tumors and muscles demonstrated similar tumor-to-background ratio (TBR) with [18F]MEL050 and [18F]FDG in subcutaneous tumors and higher TBR with [18F]MEL050 than with [18F]FDG in pulmonary metastases. CONCLUSION: We successfully implemented the radiosynthesis of [18F]MEL050 using the AllInOne™ module, including HPLC purification and formulation. In vivo PET/CT validation of [18F]MEL050 was obtained in mouse models of pigmented melanoma, where higher [18F]MEL050 uptake was observed in sub-millimetric pulmonary metastases, comparatively to [18F]FDG.

Priming Dental Pulp Stem Cells With Fibroblast Growth Factor-2 Increases Angiogenesis of Implanted Tissue-Engineered Constructs Through Hepatocyte Growth Factor and Vascular Endothelial Growth Factor Secretion.

Tissue engineering strategies based on implanting cellularized biomaterials are promising therapeutic approaches for the reconstruction of large tissue defects. A major hurdle for the reliable establishment of such therapeutic approaches is the lack of rapid blood perfusion of the tissue construct to provide oxygen and nutrients. Numerous sources of mesenchymal stem cells (MSCs) displaying angiogenic potential have been characterized in the past years, including the adult dental pulp. Establishment of efficient strategies for improving angiogenesis in tissue constructs is nevertheless still an important challenge. Hypoxia was proposed as a priming treatment owing to its capacity to enhance the angiogenic potential of stem cells through vascular endothelial growth factor (VEGF) release. The present study aimed to characterize additional key factors regulating the angiogenic capacity of such MSCs, namely, dental pulp stem cells derived from deciduous teeth (SHED). We identified fibroblast growth factor-2 (FGF-2) as a potent inducer of the release of VEGF and hepatocyte growth factor (HGF) by SHED. We found that FGF-2 limited hypoxia-induced downregulation of HGF release. Using three-dimensional culture models of angiogenesis, we demonstrated that VEGF and HGF were both responsible for the high angiogenic potential of SHED through direct targeting of endothelial cells. In addition, FGF-2 treatment increased the fraction of Stro-1+/CD146+ progenitor cells. We then applied in vitro FGF-2 priming to SHED before encapsulation in hydrogels and in vivo subcutaneous implantation. Our results showed that FGF-2 priming is more efficient than hypoxia at increasing SHED-induced vascularization compared with nonprimed controls. Altogether, these data demonstrate that FGF-2 priming enhances the angiogenic potential of SHED through the secretion of both HGF and VEGF.

¹8F-FDG PET/CT for the Early Evaluation of Response to Neoadjuvant Treatment in Triple-Negative Breast Cancer: Influence of the Chemotherapy Regimen.

UNLABELLED: Patients with triple-negative breast cancer (TNBC) have poor outcome when pathologic complete response (pCR) is not reached after neoadjuvant chemotherapy. Early prediction would be helpful. We evaluated the association between metabolic response after 2 cycles of neoadjuvant chemotherapy, pCR, and outcome in patients receiving 2 different anthracycline-based regimens (conventional and intensified). METHODS: Of 77 consecutive TNBC patients, 23 received EC-D (4 cycles of epirubicin + cyclophosphamide followed by 4 cycles of docetaxel at conventional doses) and 55 received a dose-intensified, dose-dense concomitant regimen of epirubicin + cyclophosphamide (historically called SIM) for 6 cycles. PET/CT with (18)F-FDG was performed at baseline and after 2 cycles of neoadjuvant chemotherapy. The associations between clinical factors, biologic factors, early metabolic change, pCR, and event-free survival (EFS) were examined (log-rank test). RESULTS: Of the 78 patients, 29 (37%) achieved pCR. The change in SUVmax (∆SUVmax) after 2 cycles was more pronounced in patients who achieved pCR (-72% vs. -42%;P< 0.0001). ∆SUVmax was more pronounced under SIM than under EC-D (-68% vs. -35%, P= 0.009), and there was a trend for a higher pCR rate (44% vs. 22%, P= 0.078). Twenty-two patients relapsed and 10 of them died (median follow-up, 34 mo). pCR was associated with EFS (log-rank, P= 0.001). ∆SUVmax was also significantly associated with EFS both in patients receiving SIM (P= 0.028) and in those receiving EC-D (P= 0.021). The optimal ∆SUVmax for predicting pCR and EFS was, however, specific to the treatment regimen. EFS was not associated with tumor grade (P= 0.98), histologic subtype (P= 0.17), or clinical stage (P= 0.097). CONCLUSION: Early metabolic change during neoadjuvant chemotherapy can predict pathologic response and EFS in TNBC patients under different chemotherapy regimens. However, the metabolic response varies with the type of chemotherapy.

18F-Choline PET/CT and Prostate MRI for Staging Patients With Biochemical Relapse After Irradiation for Prostate Cancer.

PURPOSE: The aim of this study was to assess the value of combining MRI and F-fluorocholine (FCH) PET/CT for patients with a biochemical relapse (BR) after prostate radiotherapy or brachytherapy. PATIENTS AND METHODS: All patients with a BR (BR definition: nadir prostate-specific antigen, +2 ng/mL) had a multiparametric MRI and FCH PET/CT if there was no clinical sign of relapse. Identification of the relapse was considered positive if both imaging techniques were concordant or in case of pathological relapse confirmation. RESULTS: Sixty-five consecutive patients were analyzed. Initial treatment was external beam radiation therapy (EBRT; n = 40), surgery followed by EBRT (n = 11), or brachytherapy (n = 14). Gleason score was 6 in 23 patients, 7 in 35 patients, and 8 to 10 in 7 patients. Median prostate-specific antigen value at the time of relapse was 7.6 ng/mL. Determination of relapse location was identified in 46 patients (70.7%). Relapses were only local in 24 patients (37%), nodal in 16 (24.6%), and distant in 9 (14%). In 4 cases, MRI showed a local relapse not seen by FCH PET/CT. Among the 24 patients with an isolated local relapse, 13 underwent a confirmatory biopsy and 9 were positive. At the end, only 7 patients (11%) could have a salvage local treatment: cryotherapy of the prostate in 6 cases and 1 nodal EBRT. CONCLUSIONS: In case of BR after radiotherapy or brachytherapy, combining MRI and FCH PET/CT could identify the site of relapse in 70% of patients. This could facilitate the selection of the patients for local salvage treatment.

Do clinical, histological or immunohistochemical primary tumour characteristics translate into different (18)F-FDG PET/CT volumetric and heterogeneity features in stage II/III breast cancer?

PURPOSE: The aim of this retrospective study was to determine if some features of baseline (18)F-FDG PET images, including volume and heterogeneity, reflect clinical, histological or immunohistochemical characteristics in patients with stage II or III breast cancer (BC). METHODS: Included in the present retrospective analysis were 171 prospectively recruited patients with stage II/III BC treated consecutively at Saint-Louis hospital. Primary tumour volumes were semiautomatically delineated on pretreatment (18)F-FDG PET images. The parameters extracted included SUVmax, SUVmean, metabolically active tumour volume (MATV), total lesion glycolysis (TLG) and heterogeneity quantified using the area under the curve of the cumulative histogram and textural features. Associations between clinical/histopathological characteristics and (18)F-FDG PET features were assessed using one-way analysis of variance. Areas under the ROC curves (AUC) were used to quantify the discriminative power of the features significantly associated with clinical/histopathological characteristics. RESULTS: T3 tumours (>5 cm) exhibited higher textural heterogeneity in (18)F-FDG uptake than T2 tumours (AUC <0.75), whereas there were no significant differences in SUVmax and SUVmean. Invasive ductal carcinoma showed higher SUVmax values than invasive lobular carcinoma (p = 0.008) but MATV, TLG and textural features were not discriminative. Grade 3 tumours had higher FDG uptake (AUC 0.779 for SUVmax and 0.694 for TLG), and exhibited slightly higher regional heterogeneity (AUC 0.624). Hormone receptor-negative tumours had higher SUV values than oestrogen receptor-positive (ER-positive) and progesterone receptor-positive tumours, while heterogeneity patterns showed only low-level variation according to hormone receptor expression. HER-2 status was not associated with any of the image features. Finally, SUVmax, SUVmean and TLG significantly differed among the three phenotype subgroups (HER2-positive, triple-negative and ER-positive/HER2-negative BCs), but MATV and heterogeneity metrics were not discriminative. CONCLUSION: SUV parameters, MATV and textural features showed limited correlations with clinical and histopathological features. The three main BC subgroups differed in terms of SUVs and TLG but not in terms of MATV and heterogeneity. None of the PET-derived metrics offered high discriminative power.

Early Metabolic Response to Neoadjuvant Treatment: FDG PET/CT Criteria according to Breast Cancer Subtype.

PURPOSE: To investigate parameters based on fluorine 18 fluorodeoxyglucose (FDG) positron emission tomographic (PET) imaging that are best correlated with pathologic complete response (PCR) in human epidermal growth factor receptor type 2 (HER2)-positive cancer and triple-negative breast cancer (TNBC) and with partial or complete response in ER-positive/HER2-negative breast cancer. MATERIALS AND METHODS: This study was approved by institutional review board with waivers of informed written consent and included consecutive patients treated by neoadjuvant chemotherapy. Five PET examination-derived parameters were tested: standard uptake value (SUV) maximum (SUV(max)), peak (SUV(peak)), and mean (SUV(mean)), metabolically active tumor volume, and total lesion glycolysis (TLG). Absolute values at baseline PET, at PET imaging after two cycles of chemotherapy, and variation (ie, change) were measured. Correlations with pathologic response (Wilcoxon rank-sum test) and predictive power assessed (area under the curve [AUC] on the basis of receiver operating characteristic analysis) were examined. RESULTS: Included were 169 consecutive patients (mean age, 50 years). PCR was more frequent in HER2-positive tumors (16 of 33 patients [48.5%]) and TNBCs (20 of 54 patients [37%]) than in ER positive/HER2-negative tumors (four of 82 [4.9%]) (P < .001). Among patients with ER-positive/HER2-negative cancers, 33 patients had partial response. In TNBC, best association with PCR was obtained with change in SUV(max) (AUC, 0.86) or change in TLG (AUC, 0.88). In HER2-positive phenotype, absolute SUV(max) (or SUV(peak)) values at PET imaging after two cycles of chemotherapy (AUC for each cycle, 0.93) were better correlated with PCR than change in SUV(max) (AUC, 0.78; P = .11) or change in TLG (AUC, 0.62; P = .005). Regarding ER-positive/HER2-negative cancers, change in SUV(max) or change in TLG (AUC, 0.75) were parameters best correlated with partial or complete response. Baseline SUV(max) was higher in lymph nodes than in primary tumor in 31 patients. Findings were similar considering the site with highest FDG uptake. CONCLUSION: Quantitative indexes of tumor glucose use that are best correlated with pathologic response vary by phenotype: change in SUV(max) or TLG are most adequate for TNBCs and ER-positive/ HER2-negative cancers and absolute SUV(max) after two cycles of chemotherapy for HER2-positive breast cancers.

Baseline Tumor 18F-FDG Uptake and Modifications After 2 Cycles of Neoadjuvant Chemotherapy Are Prognostic of Outcome in ER+/HER2- Breast Cancer.

UNLABELLED: This study investigated whether (18)F-FDG PET/CT performed at baseline and during neoadjuvant chemotherapy (NAC) was able to early depict estrogen receptor-positive/human epidermal growth factor receptor 2-negative (ER+/HER2-) breast cancer patients with poor clinical outcome. METHODS: The NAC regimen consisted of 4 cycles of epirubicin plus cyclophosphamide, followed by 4 courses of docetaxel. The patients underwent (18)F-FDG PET/CT at baseline and after 2 cycles of chemotherapy. After completion of NAC, all patients had breast surgery with axillary lymph node dissection. We assessed the impact of 2 PET parameters, maximum standardized uptake values (SUVmax) and total lesion glycolysis, on event-free survival (EFS). RESULTS: Ninety-eight consecutive patients with clinical stage II or III ER+/HER2- breast cancer were included. (18)F-FDG PET/CT revealed distant metastases in 14 patients (14%). Overall survival was significantly shorter in these patients than in the 84 patients classified as M0 at baseline (18)F-FDG PET/CT (P < 0.001). In M0 patients, a high SUVmax at baseline was associated with shorter EFS (P < 0.001). Twelve patients had a tumor SUVmax of 10 or greater and a 3-y EFS of 49% (vs. 92% in patients with baseline SUVmax < 10). A low change in SUVmax between (18)F-FDG PET/CT examination before starting NAC and after the second cycle of chemotherapy was also associated with recurrence (P = 0.033), as was a low change in total lesion glycolysis (P < 0.001). Contrarily to PET-based prediction, the extent of pathologic response after completion of NAC (partial/complete vs. nonresponders) was poorly correlated to the risk of relapse. CONCLUSION: Baseline tumor (18)F-FDG uptake and modifications after 2 cycles of NAC are prognostic of outcome in patients with ER+/HER2- breast cancer.