Role of dynamic MRI and clinical assessment in predicting histologic response to neoadjuvant chemotherapy in bone sarcomas.

BACKGROUND: Neoadjuvant chemotherapy has become the first-line therapy in management of malignant bone tumors. Response to it is best assessed with evaluation of tumor necrosis postoperatively. This study was carried out to evaluate the role of clinical parameters and dynamic magnetic resonance imaging (MRI) to predict the histologic response before surgery.

MATERIALS AND METHODS: Our study included 14 patients (12 osteosarcoma and 2 malignant fibrous histiocytoma) with mean age of 21.8 years, treated with neoadjuvant chemotherapy followed by surgery, who were evaluated clinically and with dynamic MRI twice, before starting chemotherapy and before surgery. Clinical parameters (pain, tumor girth, maximum tumor diameter, surface temperature, and consistency) and dynamic MRI parameter (slope of signal intensity-time curve) were correlated with histologic response (percentage of necrosis) using Pearson and Spearman correlation test.

RESULTS: Significant correlation with histologic necrosis was seen in change in pain, tumor girth, maximum tumor diameter, surface temperature, and dynamic MRI slope (P<0.01). Change in consistency did not show significant correlation (P>0.05). Complete relieve of pain with reduction of >4 grades, ≥5% reduction in tumor girth, ≥8% reduction in tumor diameter, attainment of normal body temperature or decrease of ≥2°F temperature, and ≥60% reduction in slope proved to be an indicator of good histologic response.

CONCLUSIONS: Both dynamic MRI and clinical evaluation are reliable methods of assessment of response of the bone tumors to neoadjuvant chemotherapy.