RECIST 1.1 compared with RECIST 1.0 in patients with advanced renal cell carcinoma receiving vascular endothelial growth factor-targeted therapy

Abstract

OBJECTIVE. Response Evaluation Criteria in Solid Tumors (RECIST) is the most widely accepted method to objectively assess response to therapy in renal cell carcinoma (RCC) treated with vascular endothelial growth factor (VEGF)-targeted therapy. Both RECIST 1.0 and 1.1 have been used to assess response to VEGF-targeted therapies; however, systematic comparisons are lacking. MATERIALS AND METHODS. Sixty-two patients with metastatic RCC treated with VEGF-targeted therapies were retrospectively studied. Tumor measurements and response assessment according to RECIST 1.1 and RECIST 1.0 were compared, including the number of target lesions, baseline measurements, response at each follow-up, best overall response, and time to progression (TTP). Morphologic changes and new enhancement were also assessed over the course of treatment, and TTP was evaluated using morphologic change criteria in combination with RECIST 1.1. RESULTS. The number of target lesions according to RECIST 1.1 was significantly fewer than by RECIST 1.0 (median, 2 vs 4; p < 0.0001). At first imaging follow-up, the percentage change of the sums of the diameter measurements by RECIST 1.1 and RECIST 1.0 were highly concordant (R = 0.857; mean shrinkage, 12.1% by RECIST 1.1 vs 10.8% by RECIST 1.0). Best response assessment was highly concordant between the two criteria (weighted κ = 0.819). There was no evidence of a difference in TTP by the two criteria, with a median TTP of 8.9 months (95% CI for the median, 5.5-13.9) by RECIST 1.1 and 8.9 months (95% CI for the median, 5.8-13.6) by RECIST 1.0. The median TTP by RECIST 1.1 alone was 8.9 months compared with 5.6 months for RECIST 1.1 and morphologic changes combined. CONCLUSION. RECIST 1.1 and RECIST 1.0 response assessments were overall highly concordant in patients with RCC treated with VEGF-targeted therapy, with fewer target lesions according to RECIST 1.1 but no difference in TTP.

Keywords: CT; Response Evaluation Criteria in Solid Tumors (RECIST); renal cell carcinoma; tumor response assessment; vascular endothelial growth factor–targeted therapy.

Fig. 1. 63-year-old woman with metastatic renal cell carcinoma treated with sunitinib

A, CT image obtained at baseline before treatment shows large predominantly solid enhancing central liver metastasis and left nephrectomy bed metastases. B, CT image obtained 7 weeks after start of therapy shows mildly increased size yet marked central necrosis of central liver metastasis (arrow), now predominantly cystic in attenuation and representing favorable response according to morphology, attenuation, size, and structure criteria. Similar features are observed in left liver metastasis, not shown at baseline because of differences in slice selection. C, CT image obtained 11 months after start of therapy shows new solid rim enhancement at periphery of central liver metastasis without significant change in size of this lesion (arrow) and similar new rim enhancement in left liver metastasis (asterisk). New solid rim enhancement represents unfavorable morphologic change assessed in this study.

Fig. 2

Number of target lesions according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 versus that according to RECIST 1.0. Number of target lesions using RECIST 1.1 was significantly lower than that by RECIST 1.0 (Wilcoxon signed rank p < 0.0001).

Fig. 3

Comparison of baseline measurements according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 versus RECIST 1.0. High correlation was observed between sum of diameters of target lesions on baseline scans by RECIST 1.1 and 1.0 (R = 0.910).

Fig. 4. Comparison of initial percentage changes in sum of diameters of target lesions according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 versus RECIST 1.0

A, Scatterplot of initial proportional changes of sum of diameters of target lesions by two criteria shows significant correlation (R = 0.857). Concordant observations according to RECIST 1.1 and 1.0 are in bottom left, middle, and top right boxes. B, Initial percentage changes in sum of diameters of target lesions by two criteria in each patient (n = 59) were ranked by changes according to RECIST 1.0. Six patients were categorized as having stable disease by RECIST 1.0 and as having partial response by RECIST 1.1 (patients 23, 39, 40, 53, 54, and 55; thick arrows). One patient had partial response by RECIST 1.0 and stable disease by RECIST 1.1 (patient 56, arrowhead). One patient had progressive disease by RECIST 1.0 and stable disease by RECIST 1.1 (patient 1, asterisk). One patient had stable disease by RECIST 1.0 and progressive disease by RECIST 1.1 (patient 9, thin arrow).

Fig. 5

Time to progression (TTP) by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 versus RECIST 1.0. There was no evidence of difference in TTP according to RECIST 1.1 or RECIST 1.0, with median TTP of 8.9 months according to each criteria.

Fig. 6

Time to progression (TTP) by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 versus RECIST 1.1 and morphologic changes. Median TTP by RECIST 1.1 alone was 8.9 months compared with 5.6 months for RECIST 1.1 and morphologic changes combined.