Chemotherapy response evaluation using diffusion weighted MRI in Ewing Sarcoma: A single center experience

Area of Science:

• Oncology
• Radiology
• Biomarkers

Background:

• Early assessment of chemotherapeutic response in Ewing sarcoma family of tumors (ESFT) is crucial for treatment optimization.
• Non-invasive biomarkers are needed to monitor treatment efficacy in ESFT patients.

Purpose of the Study:

• To evaluate the utility of diffusion-weighted magnetic resonance imaging (MRI) for early prediction of chemotherapeutic response in ESFT.
• To assess the role of apparent diffusion coefficient (ADC) and normalized ADC (nADC) in monitoring treatment response.

Main Methods:

• Prospective analysis of 28 ESFT patients undergoing 1.5-T MRI at baseline, after the first chemotherapy cycle, and at the end of treatment.
• Tumor diameter, ADC, and nADC values were measured and analyzed.
• RECIST 1.1 criteria were used to categorize patients into responders and non-responders.

Main Results:

• Baseline nADC was significantly lower in responders compared to non-responders (P=0.033), with an AUC of 0.735 for predicting response.
• After the first chemotherapy cycle, responders showed a significantly greater reduction in tumor diameter (P=0.002) and a higher increase in ADC (P=0.039) and nADC (P=0.008) compared to non-responders.
• Changes in tumor diameter, ADC, and nADC after the first cycle demonstrated high accuracy (AUCs 0.890, 0.723, 0.756) in identifying chemotherapy response.

Conclusions:

• Baseline nADC can serve as a non-invasive marker for predicting early chemotherapeutic response in ESFT.
• Changes in nADC after the first chemotherapy cycle are valuable surrogate markers for early treatment response assessment in ESFT patients.