Clinical Evaluation of Neoadjuvant Chemotherapy for Primary Malignant Sarcomas That Originate in Bone

Clinical Evaluation of Neoadjuvant Chemotherapy for Primary Malignant Sarcomas That Originate in Bone: a Multi-center Retrospective Study for Standardization and Modification of Response Evaluation Criteria

For bone lesions treated with chemotherapy or targeted therapy, particularly for sarcomas that originate in bones, Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 is spurious because bone lesions are typically located in irregularly shaped bones, are difficult to measure accurately, and usually respond more slowly to treatment than soft tissue lesions. Positron Emission Tomography Response Criteria in Solid Tumors (PERCIST) allows for response to be measured in the absence of anatomic changes through assessment of metabolic activity. It does not, however, account for morphologic changes. This study evaluated whether clinical imaging findings of sarcomas after preoperative chemotherapy correlate with tumor responses by pathological evaluation using the rate of necrosis to develop reliable and quantitative clinical response criteria.

We reviewed a total of 190 primary lesions by clinical imaging, including X-ray, computed tomography (CT), magnetic resonance imaging, and bone scan or PET/CT in patients who received neoadjuvant chemotherapy. All patients had curative surgery of those lesions at Peking University People's Hospital or Peking University Shougang Hospital. Pathological evaluation was completed by determination of the tumor necrosis rate following Huvos' description. We also performed statistical diversity analysis for different pathological groups and generated receiver operating characteristic curves (ROC) to define the thresholds to distinguish different pathological groups.

Inclusion Criteria:

• (1) patients with high-grade sarcoma that originated in bone and confirmed histologically;
• (2) patients who routinely received neoadjuvant chemotherapy according to Peking University People's Hospital chemo-protocols (PKUPH-OS and PKUPH-ES);
• (3) patients who had primary tumor resection with assessment of histological response according to literatures;
• (4) patients who had intact pre- and post-neoadjuvant chemotherapy imaging, which included X-ray, contrasted computed tomography (CT), and magnetic resonance imaging (MRI) of the primary lesions as well as chest CT (with each layer ≤5 mm), bone scan, or [18F]2-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET);
• (5) patients for whom follow-up information and evaluation after chemotherapy were available.

Exclusion Criteria:

• patients with incomplete medical materials;
• patients without surgery of the primary site/ without pathological analysis of the specimens;