The utility of a somatostatin-type receptor binding peptide radiopharmaceutical (P829) in the evaluation of solitary pulmonary nodules

Objective: Many neoplasms including small cell cancers more densely express somatostatin-type receptors or more avidly bind somatostatin than granulomatous anti other nonmalignant processes. While non-small cell neoplasms of the lung have not let been shown to demonstrate this receptor expression, previous studies have documented non-small cell lung cancer detection with somatostatin analog scintigraphy. This phenomenon can be conceivably exploited utilizing technetium Tc-99m P829 (P829), a unique low molecular weight somatostatin-type receptor binding polypeptide radiopharmaceutical, The objective of this study was to determine the ability of P829 scintigraphy to noninvasively differentiate malignant and nonmalignant solitary pulmonary nodules (SPNs), Methods: The radiopharmaceutical technetium Tc-99m-P829 was utilized for scintigraphy including single photon emission computed tomography. Thirty individuals with indeterminate SPNs of greater than or equal to 1 cm and significant risk factors for primary lung cancer were identified and underwent P829 scintigraphy. Tissue diagnosis nps then established by transthoracic needle biopsy specimens. Results: Fourteen subjects demonstrated abnormal P829 scans in the region of the radiographic abnormality. Twelve of this group had biopsy specimens revealing neoplasia. Two subjects with necrotizing granuloma on biopsy specimen had abnormal P829 scans in the region of the nodule, Sixteen subjects had no abnormal P829 tracer uptake in the region of the nodule, Foul teen subjects had benign diagnoses on biopsy specimens. One member of this group with a non-diagnostic biopsy specimen refused thoracotomy and remains radiographically stable at 24 months of follow-up. One subject with a squamous cell carcinoma demonstrated no P829 activity in the region of the nodule, The specificity of P829 scintigraphy based on transthoracic needle biopsy specimen was 88%. The sensitivity was 93%. P829 scintigraphy correctly identified or excluded malignancy in 27 of 30 subjects. Conclusions: P829 scintigraph reliably identified or excluded malignancy in radiographically indeterminate solitary pulmonary nodules, The sensitivity and specificity compared favorably with the reported results of F-18 fluorodeoxyglucose positron emission tomographic imaging.