Abstract 699: Clinical feasibility of chemotherapy monitoring for bone sarcoma patients with diffuse optical spectroscopic imaging

Abstract

Abstract Background: Sarcomas account for almost 15% of all childhood cancers and 40-60% of these patients develop locally recurrent or metastatic disease. Currently in many sarcomas, the only clinically accepted prognostic marker in patients with localized disease is the percent of tumor necrosis at the time of surgery. Diffuse Optical Spectroscopic Imaging (DOSI) is an emerging near-infrared (NIR) imaging technique that non-invasively measures quantitative functional information and may provide a new means to monitor and predict chemotherapy response in sarcoma which could impact treatment decisions. Here we evaluate the feasibility of measuring pediatric sarcomas with DOSI. Methods: Patients diagnosed with either Ewing’s Sarcoma or osteosarcoma underwent DOSI measurement at multiple time points during their course of neoadjuvant chemotherapy. A handheld probe was used to take point measurements in a 1 cm spaced grid at tumor and contralateral normal locations. The measurement area was approximately 6 x 7 cm and a single point measurement typically took 15-30 s, which includes the time it takes to position the probe, ensure good contact between the probe and the skin, and acquire data. The optical properties, and absolute concentrations of oxyhemoglobin (ctHbO2), deoxyhemoglobin (ctHb), water (ctH2O), and lipids were compared between tumor and normal measurements. Results: To date, one osteosarcoma and two Ewing’s sarcoma patients have been measured. At baseline and early in treatment, all subjects had a statistical difference in total hemoglobin concentration between the affected and contralateral normal tissues (p < 0.05 for Student’s t-test, Kolmogorov-Smirnov test, and Mann-Whitney rank test). Statistical differences also appeared in oxyhemoglobin, deoxyhemoglobin, oxygen saturation, water, lipids, scattering amplitude, and scattering power although longitudinal trends varied across patients. Conclusions: DOSI can be utilized to measure optical properties and to obtain functional information in bone sarcoma patients. It can detect differences between affected and normal tissue. A better understanding of the optical properties in this patient population is needed. Larger data sets are needed to characterize and quantify sarcoma optical properties and treatment response dynamics, ideally finding a functional biomarker associated with pathologic response. Additional accrual of primary bone sarcoma patients and normal volunteers is ongoing. Citation Format: Hannah M. Peterson, Bang H. Hoang, David Geller, Richard Gorlick, Rui Yang, Jeremy Berger, Janet Tingling, Michael Roth, Jonathan Gill, Darren Roblyer. Clinical feasibility of chemotherapy monitoring for bone sarcoma patients with diffuse optical spectroscopic imaging [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 699. doi:10.1158/1538-7445.AM2017-699