333P - Study of searching on efficacy of immune checkpoint inhibitor for the non-small cell lung cancer using FDG-PET/CT and thallium SPECT

Background

FDG-PET/CT and Thallium SPECT (TL) which are radioisotope examination are inspection used as diagnostic imaging in the malignant tumors conventionally, and it is reported when useful for a stage diagnosis of the lung cancer. It was common to use the CT imaging according to the RECIST criteria for the effect judgment of cytotoxic agents and molecular target agents. In determining the efficacy of immune checkpoint inhibitors (ICIs), we often experienced that the assessment on CT imaging and the true effect do not match. Therefore, we planned a prospective study to evaluate whether FDG-PET/CT and TL examination is useful for ICI effect judgment. We examined the correlation between SUV differences on PET examination before treatment and 2 months after treatment initiation and RECIST evaluation.

Methods

A total of 18 advanced NSCLC patients treated at Kansai Medical University Hospital from September 2017 to September 2018 using ICI monotherapy were enrolled in this study. We examined the correlation with a PERCIST response rate and the response rate that went to the CT evaluation using RECIST1.1.

Results

The median age was 74 years. There were 15 men and three women. 15 cases were evaluable both before and two months after treatment initiatoin. There were CR/PR/SD/PD;0/3/7/5 by RECIST evaluation, and the curative effect judgment by FDG-PET were CMR/PMR/SMD/PMD; 1/3/6/5. 1 case was PD in RECIST, but was PMR in FDG-PET.The PR case tended to be higher in Tl accumulation after the treatment than an SD and PD cases.

Conclusions

The effect measurement by FDG-PET showed usefulness with more than that of RECIST evaluation and Tl-SPECT seems to have the potential to be useful in determining the effect of ICIs.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Takayasu Kurata.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.