Evaluation of the effect of preoperative chemotherapy in bone sarcomas. 99mTc-HMDP scintigraphy in 34 cases

Conventional 99mTc-(hydroxy) methylene diphosphate remains useful to predict osteosarcoma response to neoadjuvant chemotherapy: Individual patient data and aggregate data meta-analyses

BACKGROUND

The current standard of chemotherapy response evaluation holds the most important prognostic factor to be the histological assessment of the tumor necrosis of the excised lesion, but the major challenge is to find an early prognostic factor that will allow the adjuvant treatment regimen to be adjusted. The objective of this systematic review is to provide an up-to-date and unprecedented summary of the value of Technetium-methylene diphosphate or -hydroxymethylene diphosphate (Tc-MDP/HMDP) scintigraphy for the preoperative evaluation of osteosarcoma response to chemotherapy.

METHODS

Studies evaluating the alteration ratio (percentage change of the Tc-99m -MDP/HMDP uptake between before and after neoadjuvant chemotherapy) to predict the histological response of osteosarcoma to chemotherapy were searched for in MEDLINE, EMBASE, and Web of Science. A meta-analysis of individual patient data (IPD) was performed to determine the optimal cut-off point from the receiver operating characteristic (ROC) curve. Additionally, aggregate data (AD) meta-analysis was performed to compare the value of Tc-MDP/HMDP scintigraphy with that of other quantitative modalities, such as dynamic magnetic resonance imaging (MRI), Tl scintigraphy, and F-FDG PET-CT.

RESULTS

Seven studies with 154 patients were included for the IPD meta-analysis. The optimal cut-off point of the alteration ratio was 31.0%. Five studies with 123 patients were considered for the AD meta-analysis. The pooled sensitivity and specificity were 0.76 (95% CI, 0.63-0.86) and 0.89 (95% CI, 0.79-0.95), respectively. There was a significant difference between the good and poor responders in terms of the diagnostic odds ratio. The summary ROC curve demonstrated that the area under curve (AUC) was 0.892, indicating excellent diagnostic accuracy.

CONCLUSION

Our findings have suggested that conventional Tc-MDP/HMDP scintigraphy remains as useful as recent quantitative modalities to predict the histological response of osteosarcoma to neoadjuvant chemotherapy.

Comparison of 99mTc-methyl diphosphonate bone scintigraphy and 18F-fluorodeoxyglucose positron emission tomography/computed tomography to predict histologic response to neoadjuvant chemotherapy in patients with osteosarcoma

We compared the usefulness of Tc-methyl diphosphonate (Tc-MDP) bone scintigraphy and F-fluorodeoxyglucose (FDG) for positron emission tomography/computed tomography (PET/CT) in predicting histologic response in patients with osteosarcoma receiving neoadjuvant chemotherapy (NAC).We retrospectively reviewed 62 patients with high-grade osteosarcoma who had received 2 cycles of NAC and surgery. All patients underwent Tc-MDP bone scintigraphy and F-FDG PET/CT before and after NAC. Tc-MDP uptake in the primary tumor was measured quantitatively as the maximum tumor-to-nontumor ratio (T/NTmax) and F-FDG uptake was measured as the maximum standardized uptake value (SUVmax), before and after NAC. The percent changes of T/NTmax (percent changes of the maximum tumor-to-nontumor ratio [Δ%T/NTmax]) and SUVmax (percent changes of the maximum standardized uptake value [Δ%SUVmax]) after NAC were calculated and the correlations between these parameters were evaluated. After surgery, the effects of NAC were graded histopathologically (good vs poor) and the optimum cut-off values of Δ%T/NTmax and Δ%SUVmax for predicting histologic response were assessed using the receiver operating characteristic (ROC) curve analysis.Δ%T/NTmax and Δ%SUVmax were positively correlated with each other (r = 0.494, P < .01). Based on the ROC curve analysis, both Δ%T/NTmax (area under the curve [AUC] = .772, P < .01) and Δ%SUVmax (AUC = .829, P < .01) predicted good histologic response. However, there was no significant difference between the AUCs of Δ%T/NTmax and Δ%SUVmax (P = .44). The sensitivity and specificity for predicting good histologic response were 83.3% and 75.0%, for the criterion Δ%T/NTmax <-12.5%, and 80.0% and 81.3% for the criterion Δ%SUVmax <-49.0%, respectively.The Tc-MDP bone scan and F-FDG PET scan are non-inferior to each other in predicting the histologic response of osteosarcoma treatments. The Tc-MDP bone scan and F-FDG PET scan showed respective advantages with differing features. Therefore, physicians should consider which scan is appropriate for their own institute based on the advantages of each scan and the circumstances of the institute.

Treatment effects in pediatric soft tissue and bone tumors: practical considerations for the pathologist

Dramatic improvements in survival for children with cancer have led to increased numbers of posttreatment pathologic specimens, particularly in bone and soft tissue sarcomas. Current therapeutic protocols in North America require specific pathologic classification and stratify patients based on clinical, biologic, and pathologic features. For osteosarcoma, the pathologic response to therapy predicts prognosis and modifies the treatment regimen. Ongoing studies aim to assess the response to therapy and outcome in other types of soft tissue and bone tumors. The pathologic evaluation of pretreatment and posttreatment specimens is critical for therapeutic decisions and prognostic assessment. A standardized approach to posttherapy pathologic specimens, with attention to appropriate use of ancillary tests, and assessment of clinical and biologic significance of therapy-induced pathologic changes has significance for patient management and treatment protocols.

The role of nuclear medicine in monitoring treatment in skeletal malignancy

The nuclear medicine bone scan has historically been one of the most common investigations to stage and monitor skeletal malignancy. Current guidelines for using radiographs to assess the response of skeletal metastases to systemic therapy are limited in their ability to give a timely result. Despite some minor limitations caused by the flare phenomenon, skeletal scintigraphy remains widely used for this purpose, both clinically and in trials of new cancer treatments. Nuclear medicine has also played an important role in the posttherapy evaluation of primary bone tumors, both with bone agents and nonspecific tumor agents, such as 201Tl. In the future, it is possible that positron emission tomography radiopharmaceuticals such as 18F-fluorodeoxyglucose may prove to be superior in predicting and measuring treatment response in primary and metastatic bone and bone marrow disease, but further work is required in this area.

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.