(18)F-fluorodeoxyglucose positron emission tomography versus computed tomography in predicting histopathological response to epidermal growth factor receptor-tyrosine kinase inhibitor treatment in resectable non-small cell lung cancer.

PURPOSE: To prospectively evaluate diagnostic computed tomography (CT) and (18)F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) for identification of histopathologic response to neoadjuvant erlotinib, an epidermal growth factor receptor-tyrosine kinase inhibitor in patients with resectable non-small cell lung cancer (NSCLC). METHODS: This study was designed as an open-label phase 2 trial, performed in four hospitals in the Netherlands. Patients received preoperative erlotinib 150 mg once daily for 3 weeks. CT and FDG-PET/CT were performed at baseline and after 3 weeks of treatment. CT was assessed according to the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. FDG-PET/CT, tumor FDG uptake, and changes were measured by standardized uptake values (SUV). Radiologic and metabolic responses were compared to the histopathological response. RESULTS: Sixty patients were enrolled onto this study. In 53 patients (22 men, 31 women), the combination of CT, FDG-PET/CT, and histopathological evaluation was available for analysis. Three patients (6 %) had radiologic response. According to European Organisation for Research and Treatment of Cancer (EORTC) criteria, 15 patients (28 %) showed metabolic response. In 11 patients, histopathologic response (≥50 % necrosis) was seen. In predicting histopathologic response, relative FDG change in SUVmax showed more SUVmax decrease in the histopathologic response group (-32 %) versus the group with no pathologic response (-4 %) (p = 0.0132). Relative change in tumor size on diagnostic CT was similar in these groups with means close to 0. CONCLUSIONS: FDG-PET/CT has an advantage over CT as a predictive tool to identify histopathologic response after 3 weeks of EGFR-TKI treatment in NSCLC patients.

Tumor response and toxicity of neoadjuvant erlotinib in patients with early-stage non-small-cell lung cancer.

PURPOSE: The development of targeted therapy has introduced new options to improve treatment outcome in selected patients. The objective of this prospective study was to investigate the safety of preoperative erlotinib treatment and the (in vivo) response in patients with early-stage resectable non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: This study was designed as an open-label phase II trial, performed in four hospitals in the Netherlands, according to a Simon's minimax two-stage procedure. Initially, operable patients with early-stage NSCLC (n = 15) were entered from an enriched population (never-smoker, female sex, nonsquamous histology, or Asian ethnicity); thereafter, unselected patients were included to a total of N = 60. Patients received preoperative erlotinib 150 mg once daily for 3 weeks. Response to treatment was evaluated using [18F] fluorodeoxyglucose positron emission tomography (PET) and computed tomography (CT) scans during treatment and histologic examination of the resection specimen. Primary end points were toxicity and pathologic response. RESULTS: Sixty patients were included. Seven patients stopped treatment prematurely (12%). Skin toxicity was present in 37 patients (62%), and diarrhea was present in 21 patients (35%). PET evaluation revealed metabolic response (> 25% standardized uptake value decrease) in 16 patients (27%); CT evaluation using Response Evaluation Criteria in Solid Tumors (RECIST) showed response in three patients (5%). At surgery, no unexpected complications occurred. Pathologic examination showed more than 50% necrosis in 14 patients (23%), of whom three (5%) had more than 95% tumor necrosis. The response rate in the enriched population was 34% (10 of 29 patients). CONCLUSION: According to predefined criteria, neoadjuvant erlotinib has low toxicity and sufficient activity to deserve further testing in future studies in an enriched population.

Is 18F-FDG PET/CT useful for the early prediction of histopathologic response to neoadjuvant erlotinib in patients with non-small cell lung cancer?

UNLABELLED: Early prediction of treatment response is of value in avoiding the unnecessary toxicity of ineffective treatment. The objective of this study was to prospectively evaluate the role of integrated (18)F-FDG PET/CT for the early identification of response to neoadjuvant erlotinib, an epidermal growth factor receptor tyrosine kinase inhibitor. METHODS: From October 2006 to March 2009, 23 patients with non-small cell lung cancer eligible for surgical resection were evaluated for this study. Patients received preoperative erlotinib (150 mg) once daily for 3 wk. (18)F-FDG PET/CT was performed before and at 1 wk after the administration of erlotinib. Changes in tumor (18)F-FDG uptake during treatment were measured by standardized uptake values and assessed prospectively according to the criteria of the European Organization for Research and Treatment of Cancer. Patients with a decrease in standardized uptake values of 25% or more after 1 wk were classified as "metabolic responders." The metabolic response was compared with the pathologic response, obtained by histopathologic examination of the resected specimen. RESULTS: Following the (18)F-FDG PET/CT criteria of the European Organization for Research and Treatment of Cancer, 6 patients (26%) had a partial response within 1 wk, 16 patients (70%) had stable disease, and 1 patient (4%) had progressive disease. The median percentage of necrosis in the early metabolic responder group was 70% (interquartile range, 30%-91%), and the median percentage of necrosis in the nonresponder group was 40% (interquartile range, 20%-50%; P = 0.09). The kappa-agreement between the metabolic and pathologic responders was 0.55 (P = 0.008). CONCLUSION: The results of this study suggest that early during the course of epidermal growth factor receptor tyrosine kinase inhibitor therapy, (18)F-FDG PET/CT can predict response to erlotinib treatment in patients with non-small cell lung cancer.