Can MRI predict the histopathological response in patients with osteosarcoma after the first cycle of chemotherapy?

Can conventional magnetic resonance imaging at presentation predict chemoresistance in osteosarcoma?

OBJECTIVES

Histological tumour necrosis is the current indicator for the response of osteosarcoma after neoadjuvant chemotherapy. Chemoresistant tumours require close monitoring and adjustment of treatment. Characteristics of tumours on baseline MRI may be able to predict response to chemotherapy. The aim is to identify which baseline MRI findings can help predict chemoresistant osteosarcoma.

METHODS

Baseline MRI before giving neoadjuvant chemotherapy of 95 patients during 2008-2021 was reviewed by 2 musculoskeletal radiologists. Histological necrosis from surgical specimens was the reference standard. MRIs were reviewed for tumour characteristics (tumour volume, maximum axial diameter, central necrosis, haemorrhage, fluid-fluid level), peritumoural bone and soft tissue oedema, and other parameters including intra-articular extension, epiphyseal involvement, neurovascular involvement, pathologic fracture, and skip metastasis. The cut-off thresholds were generated by receiver operating characteristic curves which then tested for diagnostic accuracy.

RESULTS

Two-third of patients were chemoresistance (histological necrosis <90%). Tumour volume >150 mL, maximum axial diameter >7.0 cm, area of necrosis >50%, presence of intra-articular extension, and peritumoural soft tissue oedema >6.5 cm significantly predicted chemoresistance, particularly when found in combination. Tumour volume >150 mL and maximum axial diameter >7.0 cm could be used as an independent predictor (multivariable analysis, P-value = .025, .045).

CONCLUSIONS

Findings on baseline MRI could help predicting chemoresistant osteosarcoma with tumour size being the strongest predictor.

ADVANCES IN KNOWLEDGE

Osteosarcomas with large size, large cross-sectional diameter, large area of necrosis, presence of intra-articular extension, and extensive peritumoural soft tissue oedema were most likely to have a poor response to neoadjuvant chemotherapy.

Evaluation of response to neoadjuvant chemotherapy in osteosarcoma using dynamic contrast-enhanced MRI: development and external validation of a model

OBJECTIVE

To identify which dynamic contrast-enhanced (DCE-)MRI features best predict histological response to neoadjuvant chemotherapy in patients with an osteosarcoma.

METHODS

Patients with osteosarcoma who underwent DCE-MRI before and after neoadjuvant chemotherapy prior to resection were retrospectively included at two different centers. Data from the center with the larger cohort (training cohort) was used to identify which method for region-of-interest selection (whole slab or focal area method) and which change in DCE-MRI features (time to enhancement, wash-in rate, maximum relative enhancement and area under the curve) gave the most accurate prediction of histological response. Models were created using logistic regression and cross-validated. The most accurate model was then externally validated using data from the other center (test cohort).

RESULTS

Fifty-five (27 poor response) and 30 (19 poor response) patients were included in training and test cohorts, respectively. Intraclass correlation coefficient of relative DCE-MRI features ranged 0.81-0.97 with the whole slab and 0.57-0.85 with the focal area segmentation method. Poor histological response was best predicted with the whole slab segmentation method using a single feature threshold, relative wash-in rate <2.3. Mean accuracy was 0.85 (95%CI: 0.75-0.95), and area under the receiver operating characteristic curve (AUC-index) was 0.93 (95%CI: 0.86-1.00). In external validation, accuracy and AUC-index were 0.80 and 0.80.

CONCLUSION

In this study, a relative wash-in rate of <2.3 determined with the whole slab segmentation method predicted histological response to neoadjuvant chemotherapy in osteosarcoma. Consistent performance was observed in an external test cohort.

Prediction of response to preoperative neoadjuvant chemotherapy in extremity high-grade osteosarcoma using X-ray and multiparametric MRI radiomics

PURPOSE

This study aims to evaluate the value of applying X-ray and magnetic resonance imaging (MRI) models based on radiomics feature to predict response of extremity high-grade osteosarcoma to neoadjuvant chemotherapy (NAC).

MATERIALS AND METHODS

A retrospective dataset was assembled involving 102 consecutive patients (training dataset, n = 72; validation dataset, n = 30) diagnosed with extremity high-grade osteosarcoma. The clinical features of age, gender, pathological type, lesion location, bone destruction type, size, alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) were evaluated. Imaging features were extracted from X-ray and multi-parametric MRI (T1-weighted, T2-weighted, and contrast-enhanced T1-weighted) data. Features were selected using a two-stage process comprising minimal-redundancy-maximum-relevance (mRMR) and least absolute shrinkage and selection operator (LASSO) regression. Logistic regression (LR) modelling was then applied to establish models based on clinical, X-ray, and multi-parametric MRI data, as well as combinations of these datasets. Each model was evaluated using sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) with a 95% confidence interval (CI).

RESULTS

AUCs of 5 models using clinical, X-ray radiomics, MRI radiomics, X-ray plus MRI radiomics, and combination of all were 0.760 (95% CI: 0.583-0.937), 0.706 (95% CI: 0.506-0.905), 0.751 (95% CI: 0.572-0.930), 0.796 (95% CI: 0.629-0.963), 0.828 (95% CI: 0.676-0.980), respectively. The DeLong test showed no significant difference between any pair of models (p > 0.05). The combined model yielded higher performance than the clinical and radiomics models as demonstrated by net reclassification improvement (NRI) and integrated difference improvement (IDI) values, respectively. This combined model was also found to be clinically useful in the decision curve analysis (DCA).

CONCLUSION

Modelling based on combination of clinical and radiomics data improves the ability to predict pathological responses to NAC in extremity high-grade osteosarcoma compared to the models based on either clinical or radiomics data.

Mediating effect assessment of ifosfamide on limb salvage rate in osteosarcoma: A study from a single center in China

Osteosarcoma is one of the most prevalent primary bone malignancies in children and adolescents. Surgery and chemotherapy are the standard treatment methods of osteosarcoma. Methotrexate, adriamycin, and cisplatin, and methotrexate, adriamycin, cisplatin, and ifosfamide regimens are both first-line neoadjuvant chemotherapy regimens for osteosarcoma. Moreover, the use of ifosfamide is highly controversial. Most studies of ifosfamide focused on the overall survival rate and event-free survival rate; few studies concentrated on surgical options. We conducted this retrospective study to compare the baseline characteristic of amputation and limb salvage osteosarcoma patients. Furthermore, we analyzed the direct and indirect roles in surgical decision-making and found that ifosfamide may play a partial mediating role in the surgery option choice by mediating tumor mass volume change, tumor response, and the shortest distance from the center of main blood vessels to the margin of the tumor lesion.

Prediction of Response to Induction Chemotherapy Plus Concurrent Chemoradiotherapy for Nasopharyngeal Carcinoma Based on MRI Radiomics and Delta Radiomics: A Two-Center Retrospective Study

Objective

We aimed to establish an MRI radiomics model and a Delta radiomics model to predict tumor retraction after induction chemotherapy (IC) combined with concurrent chemoradiotherapy (CCRT) for primary nasopharyngeal carcinoma (NPC) in non-endemic areas and to validate its efficacy.

Methods

A total of 272 patients (155 in the training set, 66 in the internal validation set, and 51 in the external validation set) with biopsy pathologically confirmed primary NPC who were screened for pretreatment MRI were retrospectively collected. The NPC tumor was delineated as a region of interest in the two sequenced images of MRI before treatment and after IC, followed by radiomics feature extraction. With the use of maximum relevance minimum redundancy (mRMR) and least absolute shrinkage and selection operator (LASSO) algorithms, logistic regression was performed to establish pretreatment MRI radiomics and pre- and post-IC Delta radiomics models. The optimal Youden’s index was taken; the receiver operating characteristic (ROC) curve, calibration curve, and decision curve were drawn to evaluate the predictive efficacy of different models.

Results

Seven optimal feature subsets were selected from the pretreatment MRI radiomics model, and twelve optimal subsets were selected from the Delta radiomics model. The area under the ROC curve, accuracy, sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of the MRI radiomics model were 0.865, 0.827, 0.837, 0.813, 0.776, and 0.865, respectively; the corresponding indicators of the Delta radiomics model were 0.941, 0.883, 0.793, 0.968, 0.833, and 0.958, respectively.

Conclusion

The pretreatment MRI radiomics model and pre- and post-IC Delta radiomics models could predict the IC-CCRT response of NPC in non-epidemic areas.

Together Intra-Tumor Hypoxia and Macrophagic Immunity Are Driven Worst Outcome in Pediatric High-Grade Osteosarcomas

Simple Summary

Radiological and immunohistochemical data were correlated with the outcome in a retrospective monocentric cohort of 30 pediatric osteosarcomas (OTS). A necrotic volume of more than 50 cm³ at diagnosis was significantly linked to a worse overall survival (OS). Regarding immunohistochemical analyses, an overexpression of hypoxic markers, such as HIF-1α and anhydrase carbonic IX (CAIX), was significantly linked to a worse OS, while pS6-RP hyperexpression was correlated with a better survival. We also featured that CD68 positive cells, representative of macrophagic M1 polarization, were mostly associated with HIF-1α and CAIX hyperexpressions and that M2-like polarization, mostly related to CD163 positivity, was correlated to mTor activation. These findings, involving clinical, radiological and biology data, allowed us to hypothesize a dual signature association ready to use routinely in future protocols.

Abstract

Background: Osteosarcomas (OTS) represent the most common primary bone cancer diagnosed in adolescents and young adults. Despite remarkable advances, there are no objective molecular or imaging markers able to predict an OTS outcome at diagnosis. Focusing on biomarkers contributing broadly to treatment resistance, we examine the interplay between the tumor-associated macrophages and intra-tumor hypoxia. Methods: Radiological and immunohistochemical (IHC) data were correlated with the outcome in a retrospective and monocentric cohort of 30 pediatric OTS. We studied hypoxic (pS6, phospho-mTor, HIF-1α and carbonic anhydrase IX (CAIX)) and macrophagic (CD68 and CD163) biomarkers. Results: The imaging analyses were based on MRI manual volumetric measures on axial post-contrast T1 weighted images, where, for each tumor, we determined the necrotic volume and its ratio to the entire tumor volume. When they were above 50 cm³ and 20%, respectively, they correlated with a worse overall survival (p = 0.0072 and p = 0.0136, respectively) and event-free survival (p = 0.0059 and p = 0.0143, respectively). IHC assessments enable a significant statistical link between HIF-1α/CAIX hyper-expressions, CD68+ cells and a worse outcome, whereas activation of mTor pathway was linked to a better survival rate and CD163+ cells. Conclusions: This study evidenced the links between hypoxia and immunity in OTS, as their poor outcome may be related to a larger necrotic volume on diagnostic MRI and, in biopsies, to a specific IHC profile.

A Delta-radiomics model for preoperative evaluation of Neoadjuvant chemotherapy response in high-grade osteosarcoma

Background

The difficulty of assessment of neoadjuvant chemotherapeutic response preoperatively may hinder personalized-medicine strategies that depend on the results from pathological examination.

Methods

A total of 191 patients with high-grade osteosarcoma (HOS) were enrolled retrospectively from November 2013 to November 2017 and received neoadjuvant chemotherapy (NCT). A cutoff time of November 2016 was used to divide the training set and validation set. All patients underwent diagnostic CTs before and after chemotherapy. By quantifying the tumor regions on the CT images before and after NCT, 540 delta-radiomic features were calculated. The interclass correlation coefficients for segmentations of inter/intra-observers and feature pair-wise correlation coefficients (Pearson) were used for robust feature selection. A delta-radiomics signature was constructed using the lasso algorithm based on the training set. Radiomics signatures built from single-phase CT were constructed for comparison purpose. A radiomics nomogram was then developed from the multivariate logistic regression model by combining independent clinical factors and the delta-radiomics signature. The prediction performance was assessed using area under the ROC curve (AUC), calibration curves and decision curve analysis (DCA).

Results

The delta-radiomics signature showed higher AUC than single-CT based radiomics signatures in both training and validation cohorts. The delta-radiomics signature, consisting of 8 selected features, showed significant differences between the pathologic good response (pGR) (necrosis fraction ≥90%) group and the non-pGR (necrosis fraction < 90%) group (P < 0.0001, in both training and validation sets). The delta-radiomics nomogram, which consisted of the delta-radiomics signature and new pulmonary metastasis during chemotherapy showed good calibration and great discrimination capacity with AUC 0.871 (95% CI, 0.804 to 0.923) in the training cohort, and 0.843 (95% CI, 0.718 to 0.927) in the validation cohort. The DCA confirmed the clinical utility of the radiomics model.

Conclusion

The delta-radiomics nomogram incorporating the radiomics signature and clinical factors in this study could be used for individualized pathologic response evaluation after chemotherapy preoperatively and help tailor appropriate chemotherapy and further treatment plans.

The current status of MRI in the pre-operative assessment of intramedullary conventional appendicular osteosarcoma

Osteosarcoma is the commonest primary malignant bone tumour in children and adolescents, the majority of cases being conventional intra-medullary high-grade tumours affecting the appendicular skeleton. Treatment is typically with a combination of neo-adjuvant chemotherapy, tumour resection with limb reconstruction and post-operative chemotherapy. The current article reviews the role of magnetic resonance imaging (MRI) in the pre-operative assessment of high-grade central conventional osteosarcoma.

Inter-rater Variability in the Interpretation of Pre and Post Contrast MRI for Pre-Surgical Evaluation of Osteosarcoma in Long Bones in Pediatric Patients and Young Adults

BACKGROUND AND OBJECTIVES

The value of gadolinium enhanced magnetic resonance imaging (MRI) sequences for extremity osteosarcoma resection planning is unverified. We evaluate the performance of intravenous gadolinium enhanced MRI for identification of neurovascular bundle involvement (NBI) and intraarticular extension (IAE) in patients with osteosarcoma.

METHODS

Two pediatric radiologists independently analyzed MRI examinations of patients with pathology proven extremity osteosarcoma for NBI and IAE. Initial evaluation utilized only non-contrast MRI images (PRE) and, after 2 weeks, subsequent evaluation included both the pre and post contrast images (POST). Cohen's Kappa and McNemar's test were calculated to assess agreement between PRE and POST image interpretations of NBI and IAE.

RESULTS

56 patients with 90 preoperative MRI examinations were analyzed. PRE and POST interpretations were rarely discordant; 4/90 cases for NBI (Kappa 0.91) and 2/90 cases for IAE (Kappa 0.95). McNemar's test did not show a difference between PRE and POST imaging (NBI p=0.62; IAE p=0.48).

CONCLUSION

No significant difference between PRE and POST image interpretation was found. A high level of agreement between PRE and POST image interpretation suggests that pre-contrast MRI may be sufficient for pre-surgical planning for pediatric patients with long bone osteosarcoma.

Pre-Operative chemotherapy response assessed by contrast-enhanced MRI can predict the prognosis of Enneking surgical margins in patients with osteosarcoma

The method used to evaluate the response of osteosarcoma to preoperative chemotherapy before specimen resection is still unclear. The purpose of this study was to identify factors that contribute to overall survival (OS) and to discuss their roles in making a decision regarding Enneking surgical margins. Patients (109) with pathologically confirmed Enneking stage IIB osteosarcoma were retrospectively analyzed. Univariate and multivariate survival analyses were performed. Patient characteristics and chemotherapy-induced contrast-enhanced MRI changes were considered as potential factors. Changes in the tumor volume and the relative necrosis ratio measured by MRI were independent risk factors predicting the OS of patients who underwent limb-salvage surgery. For those in whom the tumor volume had decreased (VolRatio <1) or the relative necrosis ratio had increased by at least 10% (NecRatioInc ≥0.1), there was no significant difference in OS between Enneking wide and marginal margins. Variables measured by contrast-enhanced MRI could be used to evaluate chemotherapy response and increase the limb-salvage rate. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Response Evaluation Criteria in Solid Tumors (RECIST) following neoadjuvant chemotherapy in osteosarcoma

BACKGROUND

In osteosarcoma, patient survival has not changed in over 30 years. Multiple phase II trials have been conducted in osteosarcoma using the Response Evaluation Criteria in Solid Tumors (RECIST) as a primary endpoint; however, none of these have revealed new treatment strategies. We investigated RECIST in newly diagnosed patients who received neoadjuvant chemotherapy proven to be beneficial.

METHODS

Patients treated from 1986 to 2011 for newly diagnosed osteosarcoma with paired tumor imaging before and after adequate neoadjuvant chemotherapy were included in this retrospective study. Two radiologists performed independent, blinded (to image timing) RECIST measurements of primary tumor and lung metastases at diagnosis and post-neoadjuvant chemotherapy. Association between RECIST and histological necrosis and outcome were assessed.

RESULTS

Seventy-four patients met inclusion criteria. Five-year overall survival and progression-free survival (PFS) were 77 ± 7% and 61 ± 8%, respectively. No patients had RECIST partial or complete response in the primary tumor. Sixty-four patients (86%) had stable disease, and 10 (14%) had progressive disease (PD). PD in the primary tumor was associated with significantly worse PFS in localized disease patients (P = 0.02). There was no association between RECIST in the primary tumor and necrosis. There were an insufficient number of patients with lung nodules ≥1 cm at diagnosis to evaluate RECIST in pulmonary metastases.

CONCLUSIONS

PD by RECIST predicts poor outcome in localized disease patients. In bone lesions, chemotherapy proven to improve overall survival does not result in radiographic responses as measured by RECIST. Further investigation of RECIST in pulmonary metastatic disease in osteosarcoma is needed.

A phase II trial evaluating the feasibility of adding bevacizumab to standard osteosarcoma therapy

Increased vascular endothelial growth factor (VEGF) expression in osteosarcoma correlates with a poor outcome. We conducted a phase II trial to evaluate the feasibility and efficacy of combining bevacizumab, a monoclonal antibody against VEGF, with methotrexate, doxorubicin and cisplatin (MAP) in patients with localized osteosarcoma. Eligible patients received two courses of MAP chemotherapy before definitive surgery at week 10. Bevacizumab (15 mg/kg) was administered 3 days before starting chemotherapy then on day 1 of weeks 3 and 5 of chemotherapy. After surgery, patients received MAP for a total of 29 weeks; bevacizumab was added every 2 or 3 weeks on day 1 of chemotherapy at least 5 weeks after surgery. Group sequential monitoring rules were used to monitor for unacceptable bevacizumab-related targeted toxicity (grade 4 hypertension, proteinuria or bleeding, grade 3 or 4 thrombosis/embolism, and grade 2-4 major wound complications). Thirty-one patients (median age 12.8 years) with localized osteosarcoma were enrolled. No unacceptable targeted toxicities were observed except for wound complications (9 minor and 6 major), which occurred in 15 patients; none required removal of prosthetic hardware or amputation. The estimated 4-year event-free survival (EFS) rate and overall survival rate were 57.5 ± 10.0% and 83.4 ± 7.8%, respectively. Eight (28%) of 29 evaluable patients had good histologic response (<5% viable tumor) to preoperative chemotherapy. The addition of bevacizumab to MAP for localized osteosarcoma is feasible but frequent wound complications are encountered. The observed histologic response and EFS do not support further evaluation of bevacizumab in osteosarcoma.

Triple-phase contrast-enhanced MRI for the prediction of preoperative chemotherapeutic effect in patients with osteosarcoma: comparison with (99m)Tc-MIBI scintigraphy

OBJECTIVE

This study aims to determine whether (99m)Tc-MIBI scintigraphy and triple-phase contrast-enhanced magnetic resonance imaging (TCE-MRI) performed during and after preoperative chemotherapy have the power to predict final chemotherapeutic effects in patients with osteosarcoma (OS).

MATERIALS AND METHODS

Seventeen patients underwent (99m)Tc-MIBI scintigraphy and TCE-MRI before and after the middle and last courses of preoperative chemotherapy. As for (99m)Tc-MIBI scintigraphy, an uptake ratio (UR) and a reduction rate of UR (ΔUR(MIBI)) were calculated. As for TCE-MRI, a ratio of contrast to background (CTB) was calculated in the whole tumor area (WA) at each phase on dynamic T1-weighted fat suppression images. Then a ratio of signal (R(WA)) was calculated by dividing CTB at triple-phase by CTB at pre-phase.

RESULTS

Nine and eight patients showed good and poor response in histopathologic evaluation. The sensitivity, specificity, and accuracy for the prediction of histopathological chemotherapeutic effect was 44, 100, 69% in R(WA) at the first phase, 100, 75, 88% in ΔUR(MIBI) after the middle course, 88, 100, 94% in R(WA) at the first phase, and 100, 75, 88% in ΔUR(MIBI) after the last course of the preoperative chemotherapy, respectively.

CONCLUSION

Both (99m)Tc-MIBI scintigrapy and TCE-MRI can predict the tumor response in patients with OS after the completion of the preoperative chemotherapy.

Evaluation of static and dynamic MRI for assessing response of bone sarcomas to preoperative chemotherapy: Correlation with histological necrosis

OBJECTIVES

Preoperative chemotherapy plays a key role in management of bone sarcomas. Postoperative evaluation of histological necrosis has been the gold standard method of assessing response to preoperative chemotherapy. This study was done to evaluate the efficacy of static and dynamic magnetic resonance imaging (MRI) for assessing response preoperatively.

MATERIALS AND METHODS

Our study included 14 patients (12 osteosarcomas and 2 malignant fibrous histiocytomas) with mean age of 21.8 years, treated with preoperative chemotherapy followed by surgery. They were evaluated with static and dynamic MRI twice, before starting chemotherapy and again prior to surgery. Change in tumor volume and slope of signal intensity - time curve were calculated and correlated with percentage of histological necrosis using Pearson correlation test.

RESULTS

The change in dynamic MRI slope was significant (P = 0.001). Also, ≥60% reduction in slope of the curve proved to be an indicator of good histological response [positive predictive value (PPV) =80%]. Change in tumor volume failed to show significant correlation (P = 0.071). Although it showed high negative predictive value (NPV = 85.7%), PPV was too low (PPV = 57.14%).

CONCLUSIONS

Dynamic MRI correctly predicts histological necrosis after administration of preoperative chemotherapy to bone sarcomas. Hence, it can be used as a preoperative indicator of response to neoadjuvant chemotherapy. On the other hand, volumetric assessment by static MRI is not an effective predictor of histological necrosis. This study proves the superiority of dynamic contrast-enhanced study over volumetric study by MRI.

Tumour response of osteosarcoma to neoadjuvant chemotherapy evaluated by magnetic resonance imaging as prognostic factor for outcome

PURPOSE

This study evaluated the feasibility of computed magnetic resonance imaging (MRI) volumetry in conventional osteosarcomas. Secondly, we investigated whether computed volumetry provides new prognostic indicators for histological response of osteosarcomas after neoadjuvant chemotherapy.

METHODS

In a retrospective cohort study, data from the Vienna Bone Tumour Registry was used. MR images from 14 patients (male:female = 1.8, mean age 19 years) were analysed prior to and after neoadjuvant chemotherapy according to current therapy regimens. Histological response to chemotherapy was graded according to the Salzer-Kuntschik classification. Computed volumetry was performed for the intraosseous part, as well as the soft-tissue component and the tumour as a whole.

RESULTS

In a setting of appropriate radiological equipment, the method has been considered to be well implementable into clinical routine. The mean tumour volume prior to chemotherapy was 321 (±351) ml. In good responders (n = 6), overall tumour volume decreased by 47% (p = 0.345), whereas poor responders (n = 8) showed a 19% decrease (p = 0.128). Neoadjuvant multidrug therapy remarkably changed the tumour composition. This is seen in a decrease of the mean ratio of soft-tissue to intraosseous tumour volume from 8.67 in poor responders and 1.15 in good responders to 1.26 and 0.45 (p = 0.065), respectively. Interestingly, the bony compartment of good responders showed a volume increase during neoadjuvant chemotherapy (p = 0.073). However, we did not find prognostic markers for histological tumour response to pre-operative chemotherapy.

CONCLUSIONS

Separated volumetry of tumour segments revealed interesting insights into therapy-induced growth patterns. If verified in a larger study population, these results should be taken into account when planning ablative surgery.

Early response monitoring to neoadjuvant chemotherapy in osteosarcoma using sequential ¹⁸F-FDG PET/CT and MRI

PURPOSE

We evaluated the potential of sequential fluorine-18 fluorodeoxyglucose ((18) F-FDG) positron emission tomography (PET)/computed tomography (CT) and MRI (PET/MRI) after one cycle of neoadjuvant chemotherapy to predict a poor histologic response in osteosarcoma.

METHODS

A prospective study was conducted on 30 patients with osteosarcoma treated with two cycles of neoadjuvant chemotherapy and surgery. All patients underwent PET/MRI before, after one cycle, and after the completion of neoadjuvant chemotherapy, respectively. Imaging parameters [maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and tumor volume based on magnetic resonance (MR) images (MRV)] and their % changes were calculated on each PET/MRI data set, and histological responses were evaluated on the postsurgical specimen.

RESULTS

A total of 17 patients (57%) exhibited a poor histologic response after two cycles of chemotherapy. Unlike the little volumetric change in MRI, PET parameters significantly decreased after one and two cycles of chemotherapy, respectively. After one cycle of chemotherapy, SUVmax, MTV, and TLG predicted the poor responders. Among these parameters, either MTV ≥ 47 mL or TLG ≥ 190 g after one cycle of chemotherapy was significantly associated with a poor histologic response on multivariate logistic regression analysis (OR 8.98, p = 0.039). The sensitivity, specificity, and accuracy of these parameters were 71%, 85% and 77%; and 71%, 85% and 77 %, respectively.

CONCLUSION

The histologic response to neoadjuvant chemotherapy in osteosarcoma can be predicted accurately by FDG PET after one course of chemotherapy. Among PET parameters, MTV and TLG were independent predictors of the histologic response.

Tumor volume increase during preoperative chemotherapy as a novel predictor of local recurrence in extremity osteosarcoma

BACKGROUND

Known risk factors (surgical margin, tumor necrosis) of local recurrence (LR) in osteosarcoma are determined by results available after surgery. However, relations between preoperative characteristics and LR have not been clearly defined.

METHODS

We compared the clinicopathologic characteristics of 36 osteosarcoma patients with LR and 394 patients without LR after surgery. In addition, prognostic variables were evaluated to establish factors could influence LR.

RESULTS

Compared to the non-LR group, the LR group showed an increase in tumor volume ratio (TVR) during preoperative chemotherapy (P < 0.01), inadequate surgical margin (P < 0.01), and poor histologic response (P < 0.01). Univariate analysis of data from 430 patients revealed that an increased TVR (P < 0.01), inadequate surgical margin (P < 0.01), poor histologic response (P < 0.01), and nonosteoblastic pathologic subtype (P = 0.04) were negatively related to LR-free survival. In multivariate analysis, an elevated TVR (P < 0.01, relative risk = 10.26) and inadequate surgical margin (P < 0.01, relative risk = 5.91) emerged as the key prognostic factors for LR.

CONCLUSIONS

A TVR increase during preoperative chemotherapy could be used to predict patients at high risk of LR. This finding might be useful when considering surgical options to decrease the risk of LR.

UK Guidelines for the Management of Bone Sarcomas

These guidelines have been developed in order to provide an overview and a set of broad-based key recommendations for the management of patients with bone sarcomas in the UK. They have taken into consideration the most up-to-date scientific literature along with the recent recommendations by the European Society of Medical Oncology. The principles of the NICE guidance on both "improving outcomes for patients with sarcomas" and "improving outcomes with children and young people with cancer" have been incorporated. As care evolves, it is acknowledged that these guidelines will need updating. The key recommendations are that bone pain or a palpable mass should always lead to further investigation and patients with clinicoradiological findings suggestive of a primary bone tumour should be sent to a reference centre. Patients should then have their care managed at such a specialist centre by a fully accredited multidisciplinary team.

The significance of size change of soft tissue sarcoma during preoperative radiotherapy

AIM

To assess the significance of change in tumour size during preoperative radiotherapy in patients with soft tissue sarcoma (STS).

METHODS

A retrospective review of 91 cases with STS was performed. Inclusion criteria were localised extremity and truncal STS with measurable disease, older than 18 years, treated with preoperative radiotherapy and wide local excision, in the period between January 1966 and December 2005. Patients with head and neck STS, or who received neoadjuvant chemotherapy were excluded. A difference in excess of 10% of the greatest tumour diameter of the pre-radiotherapy and the post-radiotherapy MRI scans was considered as change in tumour size.

RESULTS

Increase in tumour size was noted in 28 patients (31%) (Group 1). No change or decrease in size was observed in 63 patients (Group 2). There were no significance differences in local control or overall survival rates between the 2 groups. The estimated overall actuarial local recurrence free, event-free and overall survival rates were 90.5%, 64.4%, 62.9% in Group 1, and 85.7%, 60.8%, 68.9% in Group 2 respectively.

CONCLUSION

Increase in tumour size during preoperative radiotherapy for soft tissue sarcoma does not seem to associate with inferior local tumour control or compromise survival. Lack of reduction in tumour size is not necessarily a sign of lack of response to preoperative radiotherapy.

Early complete response during chemotherapy predicts favorable outcome in patients with primary CNS lymphoma

In primary central nervous system lymphoma (PCNSL), 2 international prognostic scores have been developed to estimate the outcome according to certain "prognostic groups". However, these scores do not predict the individual course of a single patient under therapy. In this analysis, we addressed the question of whether early tumor remission in patients still under therapy, according to magnetic resonance imaging (MRI) criteria, helps to predict long-term outcome. Eighty-eight patients treated with 6 polychemotherapy cycles within a pilot/phase II trial underwent MRI scanning within 72 hours prior to initiation of therapy, after the second chemotherapy cycle, and after completion of chemotherapy. Response was assessed by contrast-enhanced MRI of the brain according to the Macdonald criteria. Median follow-up was 42 months (range, 0-124 months). Patients achieving a complete radiographic response after 2 courses of chemotherapy (n = 18) had a significantly longer median overall survival (OS) (not reached) and median time-to-treatment failure (TTF) (not reached) than patients with complete response (CR) after termination of treatment but with only a partial response after the second cycle (n = 24) (OS: 55 months; TTF: 32 months) (P < .01). Early complete tumor response assessed by MRI after the second of sixth scheduled chemotherapy cycles was highly predictive for both OS and TTF in patients with PCNSL treated in this series.

Prediction model of chemotherapy response in osteosarcoma by 18F-FDG PET and MRI

Response to neoadjuvant chemotherapy is a significant prognostic factor for osteosarcoma; however, this information can be determined only after surgical resection. If we could predict histologic response before surgery, it might be helpful for the planning of surgeries and tailoring of treatment. We evaluated the usefulness of (18)F-FDG PET for this purpose.

METHODS

A total of 70 consecutive patients with a high-grade osteosarcoma treated at our institute were prospectively enrolled. All patients underwent (18)F-FDG PET and MRI before and after neoadjuvant chemotherapy. We analyzed the predictive values of 5 parameters, namely, maximum standardized uptake values (SUVs), before and after (SUV2) chemotherapy, SUV change ratio, tumor volume change ratio, and metabolic volume change ratio (MVCR) in terms of their abilities to discriminate responders from nonresponders.

RESULTS

Patients with an SUV2 of less than or equal to 2 showed a good histologic response, and patients with an SUV2 of greater than 5 showed a poor histologic response. The histologic response of a patient with an intermediate SUV2 (2 < SUV2 </= 5) was found to be predictable using MVCR. A patient with an MVCR of less than 0.65 is likely to be a good responder, whereas a patient with an MVCR of greater than or equal to 0.65 is likely to be a poor responder. According to our model, the predictive values for good responders and poor responders were 97% (31/32) and 95% (36/38), respectively.

CONCLUSION

We found that combined information on (18)F-FDG PET and MRI scans, acquired before and after chemotherapy, could be used to predict histologic response to neoadjuvant chemotherapy in osteosarcoma.

Diffusion-weighted MR imaging in musculoskeletal radiology: applications in trauma, tumors, and inflammation

Diffusion-weighted imaging is a noninvasive magnetic resonance technique that is capable of measuring icroscopic movement of water molecules (ie, random or Brownian motion) within biologic tissues. Diffusion weighting is achieved with a pulsed-field gradient that leaves "static" spins unaffected but causes dephasing of spin ensembles that experience different motion histories according to their diffusion paths, with respect to the direction of the gradient. This article focuses on the interesting opportunities of the use of diffusion weighted imaging in the diagnosis of musculoskeletal diseases, including trauma, tumor, and inflammation.

Effect of increases in tumor volume after neoadjuvant chemotherapy on the outcome of stage II osteosarcoma regardless of histological response

BACKGROUND

We assessed volume changes after neoadjuvant chemotherapy and evaluated relations between tumor size changes and clinical characteristics. In addition, we sought to determine whether tumor size change influences patient outcome.

METHODS

The records of 127 patients with stage II osteosarcoma who showed more than a 15% volume change after chemotherapy were retrospectively reviewed. Patients were divided into two groups depending on whether tumors increased or decreased in size. Fisher's exact test was performed to analyze correlations between tumor size changes and clinicopathological variables. Five-year metastasis-free survival and overall survival were evaluated using univariate and multivariate analyses.

RESULTS

A total of 71 patients (55.9%) showed a decrease in tumor volume, and 56 patients (44.1%) showed an increase. An increase in tumor volume after neoadjuvant chemotherapy was found to be positively correlated with a poor histological response and subsequent metastasis. Univariate analysis identified the following parameters as poor prognostic factors: age < or = 15 years (P = 0.03), American Joint Committee on Cancer (AJCC) stage IIB (P = 0.02), a subtype other than osteoblastic (P < 0.01), a poor histological response (P < 0.001), and increased tumor volume after preoperative chemotherapy (P < 0.0001). Multivariate analysis revealed that AJCC stage IIB (P = 0.006) and an increase in tumor volume after preoperative chemotherapy (P < 0.001) both independently shortened metastasis-free survival. However, a poor histological response lost its prognostic significance (P = 0.34).

CONCLUSIONS

Increased tumor volume after neoadjuvant chemotherapy independently shortened metastasis-free and overall survival in AJCC stage II osteosarcoma patients. Tumor volume changes may serve as a basis for risk-adapted therapy when used in combination with other prognostic factors.

Tumor necrosis rate adjusted by tumor volume change is a better predictor of survival of localized osteosarcoma patients

BACKGROUND

We assessed whether new parameter that considers both tumor volume change and necrosis rate predicts metastasis-free survival of localized osteosarcoma patients. We also evaluated relationship between tumor volume change and necrosis rate or metastasis-free survival.

METHODS

We retrospectively reviewed 151 patients with stage II osteosarcoma who were treated with surgery and neoadjuvant chemotherapy. The tumor volume change was measured and calculated based on pre- and postchemotherapy magnetic resonance images. The mean metastasis-free interval was 83.1 months. We calculated adjusted tumor necrosis rate as following formula: 100 - (100 - necrosis rate) x postchemotherapy/prechemotherapy tumor volume. Survival and logistic regression analyses were used to evaluate the correlation among size parameters, tumor necrosis rate and survival.

RESULTS

The 5-year metastasis-free survival rate of 151 patients was 71.4% (95% CI, 67.7-75.1%). American Joint Committee on Cancer (AJCC) stage IIB (RR 2.27; 95% CI, 1.11-4.62; P = 0.025) and poor adjusted tumor necrosis rate (RR 2.02; 95% CI, 1.05-3.89; P = 0.035) independently correlated with metastasis-free survival period. Further, tumor volume change independently correlated with necrosis rate. Decreased tumor volume could predict good response, with sensitivity of 80.2%, specificity of 68.6%, and positive predictive value (PPV) of 74.7%. Increased or stable tumor volume could predict poor response, with sensitivity of 68.6%, specificity of 80.2%, and PPV of 75.0 %.

CONCLUSION

The necrosis rate adjusted by the tumor volume change is an independent prognostic factor in osteosarcoma. This adjusted tumor necrosis rate may serve as a basis for risk-adapted therapy in combination with other prognostic factors.

Tumor volume change after chemotheraphy as a predictive factor of disease free survival for osteosarcoma

Change in tumor volume after chemotherapy appears to have a prognostic significance for the outcome of osteosarcoma. A newly developed volume measurement method based on three-dimensional summation with a proved reproducibility was utilized to measure osteosarcoma tumor volume. This retrospective analysis included 38 patients with biopsy- proven, nonsurface, skeletal high-grade osteosarcoma. The treatment was started by using three cycles of preoperative chemotherapy with cisplastin (100 mg/m2) and adriamycin (30 mg/m2). The tumor volume was measured before and after preoperative chemotherapy using three-dimensional magnetic resonance image measurement. The percentage of tumor necrosis was assessed by pathologic exam. After three cycle of postoperative chemotherapy, the patients were followed up at regular interval. For the 23 good responder patients, the mean survival time was 73.2 months (95% confidence interval 61.9-84.5 months), and for the 15 poor responder patients, the mean survival time was 50.8 months (95% confidence interval 38.6-63.1 months) (p<0.05). For the 14 patients with increased tumor volume after chemotherapy, the mean survival time was 47.5 months (range: 36.3-58.6 months) and for the 24 patients with stable or decreased tumor volume, the mean survival time was 74.3 months (range: 63.79-84.88 months) (p<0.05). Among the various factors, histopathologic response and tumor volume change after chemotherapy predicted disease free survival (p<0.05). Change in the tumor volume that was measured with a reproducible method and the histopathologic response after chemotherapy were the important predictors of disease free survival for osteosarcoma patients.

Tumor volume change as a predictor of chemotherapeutic response in osteosarcoma

The change in osteosarcoma tumor volume after preoperative adjuvant chemotherapy and its relationship to the histopathologic response was investigated using various reproducible volumetric methods. Tumor volume was measured before and after chemotherapy in 41 patients with osteosarcoma using an ellipsoid formula in plain radiography and magnetic resonance imaging and three-dimensional magnetic resonance imaging measurement. Based on intraobserver and interobserver variability for the volumetric measurements of each method, three-dimensional magnetic resonance imaging measurement was the most reproducible. In three-dimensional magnetic resonance measurements, the correlation of the histopathologic response with absolute and relative total tumor volume changes and extraosseous volume change were significant. The good responder group showed a greater reduction in tumor volume after chemotherapy, although there was no significant difference in pretreatment tumor volume between the good and poor responder groups. The group with a decreased or stable tumor volume represented a good histopathologic response with a sensitivity of 85%, specificity of 76%, and positive predictive value of 88%. The change in tumor volume of osteosarcoma measured by three-dimensional magnetic resonance imaging could predict histopathologic response after three cycles of neoadjuvant chemotherapy.

Bone and soft tissue tumors: the role of contrast agents for MR imaging

Magnetic resonance imaging is an important modality for the imaging evaluation of musculoskeletal tumors. Although there is general agreement on the value of unenhanced MR in detection, diagnosis and staging, intravenous use of gadolinium-contrast media (gd-CM) is indicated in selected cases. The purpose of this article is to review the basic pharmacokinetic principles and imaging techniques for static and dynamic contrast-enhanced MR imaging and to highlight the most important indications for administration of gd-CM in patients with musculsokeletal tumors and tumor-like lesions: adding specificity in tissue characterization, staging of local extent and biopsy planning, monitoring preoperative chemotherapy and detection of recurrence.

Imaging assessment of the responses of osteosarcoma patients to preoperative chemotherapy: angiography compared with thallium-201 scintigraphy

BACKGROUND

Assessment of the responses of osteosarcoma patients to preoperative chemotherapy is of clinical importance. The purpose of this study was to estimate the accuracy of angiography and thallium-201 scintigraphy, compared with histology, in assessing the responses of patients with osteosarcoma to preoperative chemotherapy.

METHODS

Nineteen patients with osteosarcoma who were diagnosed between 1992 and 1997 were studied. The findings of angiography and thallium-201 scintigraphy before and after preoperative chemotherapy were compared with the percentage of necrosis of tumor cells and the response grade as determined histologically. Quantitative analysis of the isotopic uptake by thallium-201 scintigraphy before and after chemotherapy, defined as the alteration ratio, was correlated with the percentage of tumor necrosis.

RESULTS

Angiography yielded a sensitivity of 88%, a specificity of 73%, and a predictive accuracy of positive test of 70%, whereas thallium-201 scintigraphy achieved 88%, 100%, and 100%, respectively. Both angiographic and scintigraphic assessment showed a significant correlation with response grade as determined histologically (P < 0.05 and P < 0.0003, respectively). The alteration ratio of thallium-201 scintigraphy showed a strong, highly significant correlation with the percentage of tumor necrosis (P < 0.0001).

CONCLUSIONS

A change in the tumor uptake of thallium-201 scintigraphy after preoperative chemotherapy can predict the tumor necrosis in osteosarcoma precisely. Thallium scintigraphy is a noninvasive technique and seems to be more useful than angiography in assessing the response of osteosarcoma to preoperative chemotherapy.

Osteosarcoma

Over the last several decades, significant advances have been made in our ability to understand and treat osteosarcoma. In this article we describe the diagnosis, evaluation, and treatment of patients with this disease. The surgical issues are discussed. We review the major clinical trials that have led to our current level of understanding. The current studies for the treatment of osteosarcoma are described.

Imaging assessment of the response of bone tumors to preoperative chemotherapy

Assessment of the response of bone tumors to preoperative chemotherapy is of clinical importance. The authors determined the value of 3 imaging techniques (digital subtraction angiography, thallium scintigraphy, and dynamic magnetic resonance imaging) in guiding patient management by assessing the response of 17 bone sarcomas to preoperative chemotherapy compared with histologic evaluation of the resected specimens. Digital subtraction angiography showed a sensitivity of 87.5%, specificity of 57.1%, and accuracy of 73.3%. Thallium scintigraphy (sensitivity, 85.7%; specificity, 85.7%; accuracy, 85.7%) was superior to angiography in predicting tumor responses. The results of dynamic magnetic resonance imaging were analyzed on the basis of the value of slopes, which represents the percent increase in signal intensity per minute. The differences in slope before and after chemotherapy and the postchemotherapy slope values correlated with the histologic responses. The assessment by dynamic magnetic resonance imaging showed a sensitivity of 100%, specificity of 85.7%, and accuracy of 90.9%. Thallium scintigraphy and dynamic magnetic resonance imaging were considered noninvasive, reliable techniques that had about equal ability to assess the response of bone sarcomas to preoperative chemotherapy. Dynamic magnetic resonance imaging offers major advantages in the spatial resolution and can be more readily quantitated when compared with thallium scintigraphy.

Does magnetic resonance imaging make a difference for patients with musculoskeletal sarcoma?

MR imaging has had an unparalleled impact on the treatment of patients with musculoskeletal sarcoma. Basically, the high accuracy of local staging has made the introduction of reconstructive and limb salvage procedures instead of amputation of disarticulation available to the majority of patients with musculoskeletal sarcoma. Pre-operative work-up with MRI is not only more accurate, but also much faster and cheaper than the conventional work-up. Staging is the single most important reason for performing MR imaging in patients with musculoskeletal tumours. The impact of MR specificity is less dramatic but the benefit to the patient is an increased safety margin. When diagnostic errors with devastating consequences are made nowadays, it is usually because the proper protocol has not been followed. A patient with a potentially malignant, or equivocal, musculoskeletal mass deserves to have a combined radiographic-MRI examination prior to invasive procedures. MRI does not currently have a major impact on chemotherapy decisions and colour Doppler ultrasound has a higher accuracy than MRI. However, selected cases, i.e. intraosseous tumours, dynamic Gd-enhanced MRI, can replace colour Doppler ultrasound.