Predictive Value of Early Tumor Shrinkage and Density Reduction of Lung Metastases in Patients With Metastatic Colorectal Cancer Treated With Regorafenib
The benefit of regorafenib in colorectal cancer is limited. By early measurement of size and density in lung metastases in our 42 patients we might have identified a predictive parameter that might ameliorate the cost-benefit of regorafenib. Density reduction seemed a positive predictor of progression free survival (PFS) and overall survival. Early tumor growth seemed a negative predictor for PFS and overall survival.Introduction
The benefit of regorafenib in colorectal cancer is not very pronounced. At present, there is lack of predictive biological or radiological markers. We studied if density reduction or small changes in size of lung metastases could be a predictive marker.Methods
We retrospectively measured density in size of lung metastases of all patients included in the CORRECT and CONSIGN trials at our center. Contrast-enhanced CT scan at baseline and at week 8 were compared. Data of progressive-free survival and overall survival were collected from the CORRECT and CONSIGN trials.Results
A significant difference in progressive-free survival was seen in 3 groups: response or stable disease in size (5.36 vs. 3.96 months), response in density (6.03 vs. 2.72 months), and response in corrected density (6.14 vs. 3.08 months). No difference was seen for response in size versus stable disease or progressive disease in size.Results
For overall survival, a difference was observed in the same 3 groups: response or stable disease in size (9.89 vs. 6.44 months), response in density (9.59 vs. 7.04 months), and response in corrected density (9.09 vs. 7.16 months). No difference was seen for response in size versus stable disease or progressive disease in size.Conclusion
Density reduction in lung metastases might be a good predictive parameter to predict outcome for regorafenib. Early tumor progression might be a negative predictive factor. If further validated, density reduction and early tumor progression might be useful to ameliorate the cost-benefit of regorafenib.