Technetium-99m methoxyisobutylisonitrile scintimammography for monitoring and early prediction of breast cancer response to neoadjuvant chemotherapy

Different approaches to target volume definition and boost delivery in surgery de-escalation clinical trial in breast cancer patients with pathological complete response

PURPOSE

We evaluate various approaches to target volume definition and boost delivery in patients with complete response to neoadjuvant systemic therapy (NST) who were treated by radiotherapy without a surgery.

MATERIALS AND METHODS

A pathological complete response (pCR) was diagnosed in 21 of 27 patients included in "surgery de-escalation" prospective observation study. Clips were placed in the primary tumor volume (PrTV) before NST and during the vacuum aspiration biopsy. Twenty patients with pCR underwent the whole breast irradiation and a boost to the PrTV. High-dose rate brachytherapy (HDRB) was the basic technique for boost delivery. Finally, we identified the value of fused images (computed tomography [CT] before NST with simulation CT), clips and their combination for an accurate boost delivery.

RESULTS

A complete overlap between PrTV on pre-treatment CT with the localization of the clips on simulation CT was mentioned in 10, partial mismatch in three patients. In 12 of these 13 women, HDRB was successfully used for the boost delivery. In five cases we mentioned a marked discrepancy between the PrTV on fused images and the topography of the clips. In other two women we did not find clips on simulation CT. The fused images in five of these seven patients showed anatomical landmarks (scar, fibrosis) used for identification of the gross tumor volume. In all 20 women with pCR (average follow-up of 16.6 months), there were no locoregional recurrences.

CONCLUSION

Combination of the clips with fusion of pre-NST and simulation CTs is important for an accurate boost delivery.

99mTc-MIBI Scintigraphy for the Preoperative Assessment of Histological Response to Neoadjuvant Chemotherapy in Patients With Osteosarcoma: A Systematic Review and a Bivariate Meta-Analysis

Purpose: There have been many attempts to preoperatively evaluate the chemotherapy response of osteosarcoma patients using ^99mTc-MIBI scintigraphy. However, the evaluations were lacking in consistency. We performed this systematic review and meta-analysis to systematically evaluate the ability of ^99mTc-MIBI scintigraphy in preoperatively assessing the response of osteosarcoma patients to neoadjuvant chemotherapy. Methods: For this systematic review and meta-analysis, PubMed, Web of Science, OVID, the Cochrane Library, and CNKI were searched. Eligible studies were included based on the defined criteria. The index test was ^99mTc-MIBI scintigraphy, the reference standard was tumor necrosis rate. Quality Assessment of Diagnostic Accuracy Studies-2 was adopted for quality assessment of included studies. The statistical pooling analysis, meta-regression analysis, subgroup analysis, sensitivity analysis, and publication bias of our research were performed using STATA 15. Results: Eight articles with 189 osteosarcoma patients were included in this systematic review and meta-analysis. Our results demonstrated that the threshold effect of our meta-analysis was significant. The uptake change ratio of ^99mTc-MIBI scintigraphy had a pooled sensitivity, specificity, positive and negative likelihood ratio, diagnostic odds ratio, and the area under curve of 0.98 (0.58-1.00), 0.68 (0.47-0.84), 3.1 (1.7-5.5), 0.03 (0.00-0.90), 103 (4-3,003), and 0.91 (0.88-0.93) in preoperative assessment of response of osteosarcoma patients to neoadjuvant chemotherapy. Meta-regression analysis and subgroup analysis indicated the factors of method and cut off value may introduce the heterogeneity. The pooled sensitivity, specificity, positive and negative likelihood ratio, diagnostic odds ratio, and the area under curve of washout rate of ^99mTc-MIBI were 0.87 (0.69-0.95), 0.91 (0.75-0.97), 9.3 (3.2-27.0), 0.15 (0.06-0.37), 64 (14-301), and 0.89 (0.86-0.92), respectively. Sensitivity analysis and publication bias demonstrated our meta-analysis was reliable. Conclusion: Both the ΔUR and WR derived from ^99mTc-MIBI scintigraphy were valuable in preoperatively assessing the response of osteosarcoma patients to neoadjuvant chemotherapy, and ΔUR may possess a more outstanding diagnostic accuracy than WR.

The role of radionuclide probes for monitoring anti-tumor drugs efficacy: A brief review

Despite recent advances in the development of new therapeutic agents and diagnostic imaging modalities, cancer is still one of the main causes of death worldwide. A better understanding of the molecular signature of cancer has promoted the development of a new generation of anti-cancer drugs and diagnostic agents that specifically target molecular components such as genes, ligands, receptors and signaling pathways. However, intrinsic heterogeneity of tumors has hampered the overall success of target therapies even among patients with similar tumor types but unpredictable different responses to therapy. In this sense, post-treatment response monitoring becomes indispensable and nuclear medicine imaging modalities could provide the tools for an early indication of therapeutic efficacy. Herein, we briefly discuss the current role of PET and SPECT imaging in monitoring cancer therapy together with an update on the current radiolabeled probes that are currently investigated for tumor therapy response assessment.