Comparison Between ¹⁸F-FDG PET–Based and CT-Based Criteria in Non–Small Cell Lung Cancer Patients Treated with Nivolumab

Abstract

Because of the peculiar mechanism of action of immune checkpoint inhibitors (ICIs), evaluation of the radiologic response to them in solid tumors presents many challenges. We aimed to compare evaluation of the first response to nivolumab by means of CT-based criteria with respect to 18 F-FDG PET response criteria in non-small cell lung cancer (NSCLC) patients. Methods: Seventy-two patients with advanced NSCLC were recruited in a single-institution ancillary trial within the expanded-access program (NCT02475382) for nivolumab. Patients underwent CT and 18 F-FDG PET at baseline and after 4 cycles (the first evaluation). In cases of progressive disease, an additional evaluation was performed after 2 further cycles to confirm progression. We evaluated the treatment response on CT using RECIST 1.1 and the immune-related response criteria (irRC) and on 18 F-FDG PET using PERCIST and immunotherapy-modified PERCIST. The concordance between CT-and PET-based criteria and the capability of each method to predict overall survival were evaluated. Results: Forty-eight of 72 patients were evaluable for a first response assessment with both PET-and CT-based criteria. We observed low concordance between CT-and PET-based criteria (κ-value of 0.346 and 0.355 between PERCIST and imPERCIST and RECIST, respectively. κ-value of 0.128 and 0.198 between PERCIST and imPERCIST and irRC, respectively). Regarding overall survival, irRC could more reliably distinguish responders from nonresponders. However, thanks to the prognostic value of partial metabolic response assessed by both PERCIST and immunotherapy-modified PERCIST, PET-based response maintained prognostic significance in patients classified as having progressive disease on the basis of irRC. Conclusion: Even though the present study did not support the routine use of 18 F-FDG PET in the general population of NSCLC patients treated with ICIs, the findings suggest that metabolic response assessment has added prognostic value, potentially improving therapeutic decision making.

Role of Baseline and Post-Therapy 18F-FDG PET in the Prognostic Stratification of Metastatic Castration-Resistant Prostate Cancer (mCRPC) Patients Treated with Radium-223

“…This analysis was performed by dividing the population into tertiles for all tested variables, with the only exception of bone scan lesions whose number was divided in ≤ 6, 6-20, and > 20, as performed in a sub-analysis of the ALSYMPCA study [1]. A binary classification of response to therapy was applied to PERCIST scores due to the small numbers involved, as previously described [20]. In particular, patients showing partial metabolic response (PMR) were considered as "responders", while stable metabolic disease (SMD) and progressive metabolic disease (PMD) were classified as "non-responders".…”

Comparison of Metabolic and Morphological Response Criteria for Early Prediction of Response and Survival in NSCLC Patients Treated With Anti-PD-1/PD-L1

“…Furthermore, only few studies have been published providing a direct comparison between CTbased and PET-based criteria, most with small cohorts and in melanoma setting (22)(23)(24)(25). Only Rossi et al (26) have recently compared anatomic and metabolic criteria in NSCLC patients treated with nivolumab. In our study, we aimed to compare different response criteria in patients with advanced NSCLC treated with anti-PD-1/PD-L1 at first evaluation, after approximately 8 weeks.…”

<p>Application and Prospects of Molecular Imaging in Immunotherapy</p>

“…Compared with CTbased evaluation criteria, the evaluation criteria for immunity based on PET showed better OS. 81 Next, Annovazzi et al conducted a retrospective study that involved 18F-FDG PET/CT imaging in fifty-seven patients with metastatic melanoma treated with ipilimumab (n = 25; group 1) or with PD-1 inhibitors (n = 32; group 2). They found a high PFS rate at 1 year in responders identified by MTV and TLG (group 1, 9080% of patients were progression free at 1 year; group 2, 100100%).…”