(P 046) EVALUATION OF INTRAOPERATIVE TUMOR MARGINS IN SARCOMA WITH FLUORESCENT DYE IMAGING: A PRELIMINARY ANALYSIS OF RESULTS

Objective: Sarcomas are rare malignant tumors that are often associated with poor outcomes. Tools for intraoperative and definitive margin assessments include frozen section and permanent pathology, respectively. Our local recurrence (LR) rate is approximately 22%, consistent with published global incidences. Indocyanine green (ICG) is a safe, low-cost fluorophore dye that has shown efficacy in intraoperative margin assessment in both breast and gastrointestinal cancer surgery. Its efficacy in sarcoma surgery has yet to be proved. The purpose of our study is to evaluate the efficacy of ICG in detecting sarcoma margins intraoperatively during sarcoma surgery as well as to develop a potential protocol for utilizing ICG to guide surgeons intraoperatively during sarcoma resection surgery. We hypothesize that the use of ICG may provide accurate and rapid intraoperative evaluation of tumor margin following sarcoma excision.

Methods: This is a prospective, non-randomized clinical study of patients diagnosed with primary sarcoma. Inclusion criteria were Age >18 years and biopsy-confirmed primary soft tissue or bone pathology not previously excised. Patients were excluded if they had underlying kidney disease or an anaphylactic reaction to IV contrast dye. Patients are infused with IV ICG (2.0 mg/kg) three hours before surgery. Following tumor excision, both the excised tumor and the tumor bed were imaged using Stryker SPY-PHI imaging system and florescence intensity in terms of arbitrary perfusion units was quantified using the SPY-PHI's proprietary software system. A positive ICG margin was classified as over 77% of highest tumor immunofluorescence (Figure 1). Surgeons were blinded to ICG results and asked to fill out a survey detailing whether they believed the margins were negative. Final pathology results obtained from chart review. Statistical analysis was performed using a Chi-Square test.

Results: Twenty-One patients have been enrolled into our study, with twenty undergoing successful ICG infusion. Average age of patients was 62.4 years old (Range 27-91). Three (15%) patients had surgery for local recurrence. Two (10%) had neoadjuvant chemotherapy, and seven (35%) had neoadjuvant radiation. Four patients (20%) patients had presumed positive margins, as determined by the operating surgeon. Four patients (20%) had positive ICG. Six (30%) patients had ICG-negative margins but positive margins on final pathology (p=0.090) (Table 1).

Conclusion: While ICG has been shown to be of benefit in detecting margins in gastrointestinal and breast cancer literature, its use in sarcoma margin detection is limited. Our preliminary findings so far do not show a significant benefit in using ICG over postoperative pathological margin detection. Our biggest limitation is the relatively small sample size of our study, which precludes us from making definitive conclusions as to the efficacy of ICG in sarcoma surgery. Therefore, further investigation and more patients are needed to definitively prove whether ICG may be a viable method of detecting margins intraoperatively in sarcoma surgery.



ICG Study Abstract_CTOS Table1.docx