RF77. Surgical Impact of Pafolacianine-Based Intraoperative Molecular Imaging in Lobar Versus Sublobar Pulmonary Resection

Objective: Intraoperative molecular imaging (IMI) has gained prominence as an adjunct to traditional surgical methods in the resection of pulmonary malignancies. Pafolacianine, a folate receptor alpha-targeted tracer, is the first FDA approved targeted IMI contrast agent. Our objective was to identify whether there is a specific patient population for which pafolacianine-based IMI is most clinically impactful by analyzing the largest institutional experience.

Methods: Between July 2015 and August 2021, patients with a pulmonary nodule suspicious for malignancy were enrolled and preoperatively administered pafolacianine (0.025 mg/kg). During resection, a wavelength-specific thoracoscope was used to detect the tracer and guide tumor resection. The primary endpoint was a clinically significant event (CSE), in which IMI directly caused a meaningful change in the conduct of the operation. Demographic data, tumor histology, and fluorescence characteristics were collected prospectively.

Results: In total, 295 patients underwent pafolacianine-based IMI during pulmonary resection. Most patients were female (n=173, 58.6%), middle-aged (mean age 65.7 years), and former smokers (n=192 [65%], 39.7 mean pack years). Mean tumor size was 2.2 cm (IQR: 1.4 - 2.8 cm) and most tumors were adenocarcinoma-spectrum lesions (n=246, 72.6%). Of 339 total lesions, 238 lesions (70.2%) fluoresced with mean tumor-to-background ratio (TBR) of 3.6 (IQR: 2.4-4.3). Ninety-one patients (30.8%) underwent sublobar resection as compared to 204 patients (69.2%) who underwent lobar resection. Overall, CSEs occurred in 74 patients (25.1%). There were three categories of CSEs: localization of lesions not identifiable by white light thoracoscopy (n=50), identification of a close or positive margin (defined as margin:tumor ratio < 1; n=16), or detection of an occult synchronous malignant nodule (n=8). The CSE rate for patients that underwent sublobar resection was 38.5% compared to 19.1% for lobar resection. We found that the increased rate of CSEs in the sublobar resection group was primarily driven by detection of close margins (n=13 vs. n=3 in lobar resection).

Conclusions: Pafolacianine-based IMI yielded clinically meaningful changes in over a quarter of the operations in this series, with the highest rate of CSEs in sublobar resections. These findings suggest the routine use of IMI in small, subpleural lesions that border intersegmental planes on preoperative imaging.

Gregory Kennedy (1), Feredun Azari (2), Sonia Singhal (3), Lydia Chen (3), Viktor Gruev (4), Edward Delikatny (3), Sunil Singhal (3), (1) Stanford University, Stanford, CA, (2) Cleveland Clinic, Cleveland, OH, (3) Perelman School of Medicine, Philadelphia, PA, (4) University of Illinois, Urbana, IL

Gregory Kennedy

Rapid Fire Abstract Presenter

Gregory Kennedy is a fellow in thoracic surgery at Stanford University School of Medicine. He graduated summa cum laude from Princeton University and received an M.Phil. with First Class Honours from the University of Cambridge, where he was a Rotary Ambassadorial Scholar. He completed medical school and general surgery residency at the University of Pennsylvania School of Medicine. While in residency, he completed a postdoctoral research fellowship focusing on novel strategies for intraoperative imaging of thoracic malignancies in the lab of Dr. Sunil Singhal. With funding from an individual NIH F32 award and the Daland Fellowship in Clinical Investigation, he published over 40 papers during this time. He has received a number of national awards for his research, including the C. Walton Lillehei Research Award at the 2022 AATS meeting. He intends to pursue a career in academic thoracic surgery. 

Specialties: Thoracic