Ty Kanyn Subhawong MD, Presenter: Nothing to Disclose

Mark D. Barton MBA, BS, Abstract Co-Author: Nothing to Disclose

Juan Abelardo Augusto Pretell MD, Abstract Co-Author: Nothing to Disclose

Juan Infante MD, Abstract Co-Author: Nothing to Disclose

Jean Jose MS, DO, Abstract Co-Author: Nothing to Disclose

Sheila Conway MD, Abstract Co-Author: Nothing to Disclose

H. Thomas Temple, Abstract Co-Author: Consultant, Stryker Corporation

Soft tissue sarcomas are often treated with neoadjuvant chemo- or radiation therapy; determining when treatment effect has plateued has important treatment implications for timing of surgery.  Such decisions are often based on radiologic imaging parameters but these remain suboptimally defined. We correlated quantitative measurements of tumor volume to quantitative and qualitative assessments of percent tumor necrosis.

In this IRB-approved retrospective review, we identfied 23 patients with both pre- and post-neoadjuvant therapy MRI available for volumetric tumor assessment. Tumor volume was calculated using OsiriX by drawing a region of interest, which outlined the tumor margins across multiple contiguous slices; a pixel-thresholding technique was used to identify solidly enhancing tumor, and the percentage of necrosis from the total tumor volume was calculated using the MATLAB programming language. Subjective assessment of percent tumor necrosis was performed on a randomly selected subset of 8 patients and compared to quantitative results.

Subject mean age was 53.6 years, range 15-88, 13 males). Relative change in tumor volume correlated poorly with change in percentage necrosis, as calculated quantitatively and subjectively (Pearson r = 0.15 and -0.21, respectively). There was good correlation in absolute assessments of percent necrosis between subjective and quantitative methods (Pearson r = 0.87). Correlation between subjective and quantitative assessments of change in tumor necrosis was fair (Pearson r = 0.48).

Changes in tumor volume show little correlation with changes in percent tumor enhancement assessed subjectively and quantitatively.

Clinical decisions based on changes in soft tissue sarcoma tumor volume as a surrogate for treatment response should be made with caution; subjective assessments correlate well with more labor-intensive quantitative techniques.

Subhawong, T, Barton, M, Pretell, J, Infante, J, Jose, J, Conway, S, Temple, H, Quantitative Measurement of Tumor Cecrosis Does Not Correlate with Tumor Volume Changes: Preliminary Results.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14019055.html