Intraoperative Molecular Imaging With Pafolacianine: Histologic Characteristics of Identified Nodules

Background: With increased early detection efforts, surgery for early-stage lung cancer is expected to rise. Pafolacianine is the first FDA approved targeted optical imaging agent indicated as an adjunct for intraoperative identification of malignant and nonmalignant pulmonary lesions in adult patients with known or suspected cancer in the lung.

Methods: This is a retrospective review of the malignant and nonmalignant lesions identified by pafolacianine with intraoperative molecular imaging (IMI) in the multi-center Phase 2 and Phase 3 ELUCIDATE clinical trials. All lesions meeting the intent to treat criteria from the combined studies were included. Histopathology for malignant and nonmalignant lesions and immunohistochemistry (ICH) for folate receptor alpha (FRα) and folate receptor beta (FRβ), which pafolacianine binds to, were assessed.

Results: A total of 273 lesions resected from 191 patients were analyzed. The identification of primary and occult malignant lesions with pafolacianine in combination with standard practice was improved (P < .001) when compared to standard practice alone. A range of histologies were demonstrated including adenocarcinoma (primary and metastatic), squamous cell carcinoma, adenoid cystic carcinoma, chordoma, lymphoma, and papillary thyroid cancer. Ninety-two percent (205 of 223) of lesions tested for folate expression were positive for FRα or FRβ expression.

Conclusions: While initially intended to identify adenocarcinoma, IMI with pafolacianine targets a broad histological cross-section of malignant and nonmalignant primary and metastatic lesions in the lung. As real-world use expands, additional insight will continue to inform utility of pafolacianine in clinical practice and may broaden clinical applicability.