mTOR-inhibitor treatment of metastatic renal cell carcinoma: contribution of Choi and modified Choi criteria assessed in 2D or 3D to evaluate tumor response.

PURPOSE

To determine whether 2D or 3D Choi and modified Choi (mChoi) criteria could assess the efficacy of everolimus against metastatic renal cell carcinoma (mRCC).

METHODS

RECIST-1.1, Choi, and mChoi criteria were applied retrospectively to analyse baseline and 2-month contrast-enhanced computed tomography (CECT) images in 48 patients with mRCC enrolled in the everolimus arm of the French randomized double-blind multicentre phase III trial comparing everolimus versus placebo (RECORD-1). The primary endpoint was centrally reviewed progression-free survival (PFS) calculated from the initial RECORD-1 analysis. Mean attenuation was determined for 2D target lesion regions of interest drawn on CECT sections whose largest diameters had been measured, and for the 3D whole target lesion.

RESULTS

The median PFS was 5.5 months. The median PFS for everolimus responders defined using 3D mChoi criteria was significantly longer than for non-responders (7.6 versus 5.4 months, respectively), corresponding to a hazard ratio for progression of 0.45 (95 % CI: 0.22-0.92), with respective 1-year survival rates of 31 % and 9 %. No other 2D or 3D imaging criteria at 2 months identified patients who would benefit from everolimus.

CONCLUSIONS

At 2 months, only 3D mChoi criteria were able to identify mRCC patients with a PFS benefit from everolimus.

KEY POINTS

Choi criteria could not identify everolimus-treated patients with significantly prolonged PFS. mCHOI enabled identification of everolimus-treated mRCC patients with a PFS benefit. 3D attenuation measurement criteria appeared to perform better than single-slice measurement.