Prediction of response to neoadjuvant chemotherapy in osteosarcoma using dual-phase 18 F-FDG PET/CT

The prognostic value of baseline EARL standardized FDG PET indices in pediatric and adolescent high-grade osteosarcoma

OBJECTIVE

To investigate the prognostic value of baseline European Association of Nuclear Medicine Research Ltd. (EARL) standardized [18F]fluorodeoxyglucose positron emission tomography-computed tomography ([18F]FDG PET-CT) quantitative values for survival and to evaluate cutoff values identified in other studies.

MATERIALS AND METHODS

Pediatric and adolescent patients with high-grade osteosarcoma were included. Baseline [18F]FDG PET-CT, with EARL-accredited reconstructions, was the standard diagnostic staging procedure. Cox proportional hazard analysis for event-free survival (EFS) and overall survival (OS) was performed with clinical prognostic factors. Kaplan-Meier analysis and log-rank tests were applied to investigate the prognostic performance of the [18F]FDG PET indices.

RESULTS

In total, 66 patients were included in this study. In the univariable Cox regression analysis, peak lean-body mass corrected SUV (SULpeak) (hazard ratio (HR): 1.04), total lesion glycolysis (TLG) (HR: 1.0), and metabolic tumor volume (MTV) (HR: 1.0) were not associated with EFS or OS. Log-rank analysis showed a significant difference in EFS for all SULmax and SULpeak cutoffs. For MTVtotal the maximum Youden, and for TLGtotal, the maximum Youden and maximally selected rank cutoff resulted in a significant EFS difference. No cutoff for any measure showed a significant difference in OS between the groups. ROC curves for event status had an AUC of 0.67, 0.66, 0.64, and 0.64 for SULmax, SULpeak, MTVtotal, and TLGtotal, respectively.

CONCLUSION

In this study, the baseline EARL-standardized [18F]FDG PET indices of children and adolescents with osteosarcoma were not prognostic of EFS or OS. The proposed prognostic cutoffs from earlier studies suffer from important technical and statistical issues.

KEY POINTS

Question Prognostic value of baseline [18F]FDG PET-CT imaging markers have been reported for histologic response and survival in high-grade osteosarcoma but have not been validated for clinical practice. Findings Baseline SUVpeak, TLGtotal, and MTVtotal measured on EARL-accredited reconstructions were not prognostic factors for survival in pediatric and adolescent patients with high-grade osteosarcoma. Clinical relevance A wide range of values for SUVpeak and SUVmax cutoffs with similar prognostic value were identified, questioning the value of a single proposed cutoff. Lack of validation, with important technical and statistical issues of proposed prognostic cutoffs, limits clinical implementation.

18 F-FDG PET Metabolic Parameters for the Prediction of Histological Response to Induction Chemotherapy in Osteosarcoma and Ewing Sarcoma : A Systematic Review and Network Meta-analysis

PURPOSE

This study aimed to evaluate the ability of 18 F-FDG PET/CT metabolic parameters to predict the histological response to neoadjuvant chemotherapy in patients with osteosarcoma and Ewing sarcoma.

PATIENTS AND METHODS

This systematic review and network meta-analysis adhered to the PRISMA-NMA and Cochrane guidelines. Electronic databases were searched from January 2008 to January 2024; this search was supplemented by snowballing methods. The risk of bias was evaluated with QUADAS-2, and evidence certainty was assessed using the GRADE approach. The prognostic value of 18 F-FDG PET/CT parameters, including pretreatment and posttreatment SUVs (SUV1, SUV2 and the SUV2/SUV1 ratio), metabolic tumor volume (MTV1, MTV2, ΔMTV), and total lesion glycolysis (TLG1, TLG2, ΔTLG), was examined.

RESULTS

The meta-analysis of 18 studies (714 patients) identified the ΔTLG, ΔMTV, and SUV ratio as superior predictors of histological response. The changes in metabolic activity, as indicated by these parameters, provided a robust indication of treatment effectiveness. Baseline parameters showed limited predictive value compared with posttreatment assessments. The study's robustness was confirmed through meta-regression, which revealed that the predictive value of the SUV2 and SUV ratio was consistent across various cutoff thresholds.

CONCLUSIONS

18 F-FDG PET/CT metabolic parameters, particularly those measuring changes posttherapy, are effective in predicting the histological response in patients with osteosarcoma and Ewing sarcoma. These findings underscore the potential of 18 F-FDG PET/CT in guiding early treatment decisions, thereby enhancing personalized therapeutic approaches.

Imaging evaluation of blood supply changes after chemotherapy of osteosarcoma and its correlation with tumor necrosis rate

Background

Analysis of the tumour necrosis rate is an important method to evaluate the effect of neoadjuvant chemotherapy for osteosarcoma. However, at present, there is no specific imaging method to evaluate this effect. The purpose of this study was to evaluate the changes in blood supply after chemotherapy by measuring the CT enhancement rate and to analyse the correlation between the CT enhancement rate and the tumour necrosis rate.

Methods

Patients with primary osteosarcoma of the extremities treated in our institute from 2016 to 2017 were analysed retrospectively. In total, 103 eligible patients were enrolled in the study, including 67 males and 36 females, with an average age of 17.7 (6-54) years. Sixty cases had tumour sites in the femur, 25 in the tibia, 10 in the humerus, and eight in other sites. All patients received neoadjuvant chemotherapy including methotrexate, cisplatin + doxorubicin and ifosfamide before surgical treatment. All patients underwent enhanced CT examination of the same tumour site before and after the neoadjuvant chemotherapy protocol. The CT value before and after chemotherapy was measured and the enhancement rate was calculated. The change in the CT enhancement rate after chemotherapy was analysed. Changes in the CT enhancement rate were compared between patients with a tumour necrosis rate greater than 90% and those with one <90%.

Results

The average CT enhancement rates before and after chemotherapy were 1.68 (median 1.63, range 1.00-2.51) and 1.39 (median 1.28, range 1.00-2.83), respectively (P < 0.01). The average CT enhancement rate after chemotherapy decreased by 15.0% (median 16.7%, range -27.5-53%): 75 cases exhibited a decrease, three cases remained unchanged, and 25 cases exhibited an increase. The average enhancement rate before chemotherapy was 1.75 (median 1.68, range 1.18-2.51) in the group with a necrosis rate >90% and 1.62 (median 1.52, range 1.00-2.41) in the group with a necrosis rate < 90% (P = 0.068). The average CT enhancement rate after chemotherapy was 1.20 (median 1.21, range 1.00-1.53) in the group with a necrosis rate > 90% and 1.53 (median 1.43, range 1.00-2.83) in the group with a necrosis rate < 90% (P < 0.01). The enhancement rate of the group with a necrosis rate > 90% decreased by 29.0% (median 28%, range -2.3-53%) (P < 0.01); the enhancement rate of the group with a necrosis rate < 90% decreased by 3.8% on average (median 0.7%, range -27.5-44.5%) (P = 0.225).

Conclusion

After receiving neoadjuvant chemotherapy, most patients with osteosarcoma of the extremities exhibited reductions in the CT enhancement rate. In cases where the tumour necrosis rate was greater than 90%, the tumour blood supply was significantly reduced. This suggests that imaging evaluations based on the CT enhancement rate can be used as a reference for evaluating the preoperative effect of chemotherapy for osteosarcoma.

18F-FDG PET/CT in the Management of Osteosarcoma

Osteosarcoma is the most common type of primary malignant bone tumor. ¹⁸F-FDG PET/CT is useful for staging, detecting recurrence, monitoring response to neoadjuvant chemotherapy, and predicting prognosis. Here, we review the clinical aspects of osteosarcoma management and assess the role of ¹⁸F-FDG PET/CT, in particular with regard to pediatric and young adult patients.

Molecular features and predictive models identify the most lethal subtype and a therapeutic target for osteosarcoma

Background

Osteosarcoma is the most common primary malignant bone tumor. The existing treatment regimens remained essentially unchanged over the past 30 years; hence the prognosis has plateaued at a poor level. Precise and personalized therapy is yet to be exploited.

Methods

One discovery cohort (n=98) and two validation cohorts (n=53 & n=48) were collected from public data sources. We performed a non-negative matrix factorization (NMF) method on the discovery cohort to stratify osteosarcoma. Survival analysis and transcriptomic profiling characterized each subtype. Then, a drug target was screened based on subtypes' features and hazard ratios. We also used specific siRNAs and added a cholesterol pathway inhibitor to osteosarcoma cell lines (U2OS and Saos-2) to verify the target. Moreover, PermFIT and ProMS, two support vector machine (SVM) tools, and the least absolute shrinkage and selection operator (LASSO) method, were employed to establish predictive models.

Results

We herein divided osteosarcoma patients into four subtypes (S-I ~ S-IV). Patients of S- I were found probable to live longer. S-II was characterized by the highest immune infiltration. Cancer cells proliferated most in S-III. Notably, S-IV held the most unfavorable outcome and active cholesterol metabolism. SQLE, a rate-limiting enzyme for cholesterol biosynthesis, was identified as a potential drug target for S-IV patients. This finding was further validated in two external independent osteosarcoma cohorts. The function of SQLE to promote proliferation and migration was confirmed by cell phenotypic assays after the specific gene knockdown or addition of terbinafine, an inhibitor of SQLE. We further employed two machine learning tools based on SVM algorithms to develop a subtype diagnostic model and used the LASSO method to establish a 4-gene model for predicting prognosis. These two models were also verified in a validation cohort.

Conclusion

The molecular classification enhanced our understanding of osteosarcoma; the novel predicting models served as robust prognostic biomarkers; the therapeutic target SQLE opened a new way for treatment. Our results served as valuable hints for future biological studies and clinical trials of osteosarcoma.

A risk factor analysis for local recurrence of bone and soft tissue sarcoma treated with carbon ion radiotherapy: A retrospective cohort study at a single institution

AIM

Carbon ion radiotherapy is well-recognized as an excellent radiation modality that is suitable for treating unresectable bone and soft-tissue sarcoma of the trunk, spine, and pelvis; however, further study is needed to improve the local control rate. The current study examined the risk factors of the local recurrence of sarcomas after carbon ion radiotherapy.

METHODS

Patients with inoperable bone and soft-tissue sarcomas treated with carbon ion radiotherapy in our institute from 2010 to 2018 were retrospectively analyzed. Among them, 87 patients were eligible for this study. We divided the instances of local recurrence into two types, in-field and out-field recurrence, and evaluated the predictors for the risk of local recurrence such as the age at the treatment, sex, histopathological diagnosis, standard uptake value on fluorodeoxyglucose positron emission tomography, and the clinical target volume for each recurrence using a Cox proportional hazards model.

RESULTS

A multivariate analysis revealed that the tumors with a post-treatment standard uptake value of more than 3.84 on positron emission tomography had a significantly high risk of in-field recurrence (hazard ratio, 3.42; p = .03). Furthermore, postoperative lesions were a risk factor for out-field recurrence (hazard ratio, 3.82; p < .01).

CONCLUSION

The current study revealed that sarcomas maintaining a high glucose metabolic activity after carbon ion radiotherapy carried a risk of in-field recurrence, and the most significant risk factor of out-field recurrence was identified to be surgery before CIRT.

Is 68Ga-Prostate-Specific Membrane Antigen PET/CT Superior than 18F-FDG PET/CT for Evaluation of Metastatic Osteosarcoma?

ABSTRACT

We present the case of a 75-year-old man with osteosarcoma of the sternum in whom 68Ga-prostate-specific membrane antigen (PSMA) PET/CT showed high radiotracer activity in the primary tumor and metastatic lesions than 18F-FDG PET/CT. The present case shows that 68Ga-PSMA PET/CT is very useful for staging of osteosarcoma due to in vivo expression of PSMA. 68Ga-PSMA PET/CT can have potential effects on prognosis and in response assessment following treatment in osteosarcoma. The use of PSMA-targeted radioligand treatments may be beneficial especially in metastatic chemorefractory osteosarcoma.

Imaging of Soft Tissue Tumors

Differentiation of malignant from benign soft tissue tumors is challenging with imaging alone, including that by magnetic resonance imaging and computed tomography. However, the accuracy of this differentiation has increased owing to the development of novel imaging technology. Detailed patient history and physical examination remain essential for differentiation between benign and malignant soft tissue tumors. Moreover, measurement only of tumor size based on Response Evaluation Criteria In Solid Tumors criteria is insufficient for the evaluation of response to chemotherapy or radiotherapy. Change in metabolic activity measured by ¹⁸F-fluorodeoxyglucose positron emission tomography or dynamic contrast enhanced-derived quantitative endpoints can more accurately evaluate treatment response compared to change in tumor size. Magnetic resonance imaging can accurately evaluate essential factors in surgical planning such as vascular or bone invasion and "tail sign". Thus, imaging plays a critical role in the diagnosis and treatment of soft tissue tumors.

Musculoskeletal Tumors

Pediatric musculoskeletal tumors can arise in both bone and soft tissues. The overwhelming majority of these are benign; however, rarely, malignant neoplasms do occur. These are collectively termed sarcomas, indicating their mesenchymal origin. Sarcoma management requires careful adherence to the well-described tenets of tumor management. This article summarizes the basic principles and recent advances in the management of soft tissue and bone tumors.

Prediction and evaluation of neoadjuvant chemotherapy using the dual mechanisms of 99mTc-MIBI scintigraphy in patients with osteosarcoma

Purpose

To investigate the feasibility of applying the dual imaging mechanisms of ^99mTc-MIBI scintigraphy in predicting and evaluating the response to neoadjuvant chemotherapy in patients with osteosarcoma.

Materials and methods

Thirty patients with osteosarcoma who underwent both pre-and post-chemotherapy ^99mTc-MIBI scintigraphy were enrolled in the study. In each patient, the tumor to background ratio (T/B), tumor washout rate (WR) of MIBI and the alteration rate (AR) of tumor uptake after chemotherapy was calculated, respectively, on MIBI scintigraphy before or after chemotherapy. Based on the tumor necrosis rate histologically confirmed by tumor resection after chemotherapy, the diagnostic performance of MIBI scintigraphy was assessed in predicting tumor response with the WR of pre-chemotherapy imaging, as well as evaluating tumor response with the AR of both pre-and post-chemotherapy imaging.

Results

On pre-chemotherapy MIBI imaging, no statistical difference was found in T/B values between patients with good response and those with poor response, but the WR in patients with good response was significantly lower. Tumor WR was negatively correlated with the tumor necrosis rate (r = −0.510, P = 0.004). When WR ≤ 25% was taken as the threshold for predicting good response, a sensitivity of 100%, a specificity of 91.7% and an accuracy of 95.8% would be yielded. On post-chemotherapy imaging, T/B values both on early and delayed phases were significantly lower in responders and AR of tumor uptake was significantly higher in these responders. When AR ≥ 38% was used as the threshold for a good response, a sensitivity of 91.7%, a specificity of 94.4% and an accuracy of 93.3% would be yielded. The diagnostic coincidence rate between WR for predicting chemotherapy response and AR for evaluating chemotherapy response was 90.0% (kappa = 0.789, P < 0.001).

Conclusion

^99mTc-MIBI imaging is a useful tool for the evaluation of neoadjuvant chemotherapy in patients with osteosarcoma, and its dual mechanisms could be simultaneously used in predicting and evaluating tumor response to chemotherapy.

Imaging of Upper Limb Tumors and Tumorlike Pathology

Bone and soft tissue sarcomas are uncommon tumors that can occur within the upper extremity as well as elsewhere within the body. However, certain histopathological subtypes have increased affinity for the upper limb and even certain sites within the arm and hand. Other benign masses and tumor mimics, such as infection and traumatic lesions, are more common and imaging appearances can sometimes overlap with malignant lesions making diagnosis difficult. In this article, we explore the current options for imaging of these lesions as well as typical imaging appearances of the more common upper limb tumors.

18F-FDG PET-CT in paediatric oncology: established and emerging applications

Accurate staging and response assessment is vital in the management of childhood malignancies. Fluorine-18 fluorodeoxyglucose positron emission tomography/CT (FDG PET-CT) provides complimentary anatomical and functional information. Oncological applications of FDG PET-CT are not as well-established within the paediatric population compared to adults. This article will comprehensively review established oncological PET-CT applications in paediatric oncology and provide an overview of emerging and future developments in this domain.

Pediatric Musculoskeletal Imaging: The Indications for and Applications of PET/Computed Tomography

The use of PET/computed tomography (CT) for the evaluation and management of children, adolescents, and young adults continues to expand. The principal tracer used is 18F-fluorodeoxyglucose and the principal indication is oncology, particularly musculoskeletal neoplasms. The purpose of this article is to review the common applications of PET/CT for imaging of musculoskeletal issues in pediatrics and to introduce the use of PET/CT for nononcologic issues, such as infectious/inflammatory disorders, and review the use of 18F-sodium fluoride in trauma and sports-related injuries.

A correlation analysis between tumor imaging changes and p-AKT and HSP70 expression in tumor cells after osteosarcoma chemotherapy

This study sought to investigate osteosarcoma property changes after neoadjuvant chemotherapy and to analyze any correlation between changes with phospho-AKT (p-AKT) and heat shock protein 70 (HSP70) expression in osteosarcoma cells. Thirty patients with osteosarcoma treated at Liaocheng People's Hospital between January and October, 2016 were given an imaging examination before and after neoadjuvant chemotherapy to examine osteosarcoma tumor properties, with images scored. Immunohistochemistry was used to determine p-AKT and HSP70 expression levels, as well as tumor cell necrosis rate (TCNR), in specimens obtained before and after chemotherapy. The correlation between the imaging changes of osteosarcoma after chemotherapy and the expressions of p-AKT and HSP70 in tumor cells. Compared with pre-chemotherapy, the imaging scores of the 30 patients significantly increased after chemotherapy (P<0.05). The radiographic score of the TCNR ≥90% group was 11.3±0.5, which was significantly higher than that of the TCNR <90% group (8.7±0.3, P<0.05). p-AKT expression in osteosarcoma cells was found in 13.3% of samples (4/30 cases) after chemotherapy, which was significantly lower than prior to chemotherapy (73.3%, 22/30 cases, P<0.05). After chemotherapy, HSP70 expression in osteosarcoma cells was found in 6.7% of samples (2/30 cases), which was significantly lower than prior to chemotherapy (83.3%, 25/30 cases, P<0.05). p-AKT and HSP70 expression levels were found to be correlated with TCNR after chemotherapy (P<0.05). After chemotherapy, p-AKT and HSP70 expression levels demonstrated a positive correlation with TCNR. Tumor property changes, as uncovered by imaging, were significantly inversely correlated with tumor cell p-AKT and HSP70 expression after chemotherapy. Therefore, osteosarcoma properties, as determined through X-ray imaging, were closely related to p-AKT and HSP70 expression in osteosarcoma cells after neoadjuvant chemotherapy. The effect of chemotherapy can be evaluated by observing the above examination results.

Positron emission tomography/computed tomography for osseous and soft tissue sarcomas: A systematic review of the literature and meta-analysis

In order to elucidate the value of positron emission tomography (PET)/computed tomography (CT) in the clinical diagnosis and treatment of osseous and soft tissue malignancies, two authors independently searched the PubMed, Medline, Elsevier, Embase and Cochrane Library databases for literature published between January 2003 and February 2016, using the key words 'PET/CT', 'positron emission tomography/computed tomography', 'osseous sarcoma', 'bone tumor', 'soft tissue sarcoma' and 'neoadjuvant', to identify prospective and retrospective studies on the applicability of PET/CT on the clinical diagnosis of bone and soft tissue lesions, and evaluation of their response to neoadjuvant therapies. Data were independently extracted by the two authors and any disagreements were resolved by a third author when necessary. Extracted data were analyzed by Meta-Disc 1.6 software. As a result, 16 trials with a total of 883 patients and 2,214 lesions were included in the present study. The overall diagnostic accuracy of PET/CT exhibited a sensitivity and specificity of 0.90 (0.86-0.92) and 0.89 (0.85-0.92), respectively, and the effect of neoadjuvant therapy was assessed with a sensitivity and specificity of 0.79 (0.30-0.93) and 0.79 (0.69-0.89), respectively. Thus, it may be concluded from the present study that PET/CT is a reliable imaging method to be applied in the diagnosis and treatment of osseous and soft tissue malignancies.

Statistical assessment of treatment response in a cancer patient based on pre-therapy and post-therapy FDG-PET scans

This work arises from consideration of sarcoma patients in which fluorodeoxyglucose positron emission tomography (FDG-PET) imaging pre-therapy and post-chemotherapy is used to assess treatment response. Our focus is on methods for evaluation of the statistical uncertainty in the measured response for an individual patient. The gamma distribution is often used to describe data with constant coefficient of variation, but it can be adapted to describe the pseudo-Poisson character of PET measurements. We propose co-registering the pre-therapy and post- therapy images and modeling the approximately paired voxel-level data using the gamma statistics. Expressions for the estimation of the treatment effect and its variability are provided. Simulation studies explore the performance in the context of testing for a treatment effect. The impact of misregistration errors and how test power is affected by estimation of variability using simplified sampling assumptions, as might be produced by direct bootstrapping, is also clarified. The results illustrate a marked benefit in using a properly constructed paired approach. Remarkably, the power of the paired analysis is maintained even if the pre-image and post- image data are poorly registered. A theoretical explanation for this is indicated. The methodology is further illustrated in the context of a series of fluorodeoxyglucose-PET sarcoma patient studies. These data demonstrate the additional prognostic value of the proposed treatment effect test statistic. Copyright © 2016 John Wiley & Sons, Ltd.