*Further Therapeutic Options in Heavily Pretreated Colorectal Cancer Patients DOI: http://dx.doi.org/10.5772/intechopen.85027*

longer OS, no significant association was found between this biomarker and PFS [8]. Furthermore, multivariate analysis documented prognostic value of tumor's location in the right or left side of the abdominal cavity, with better prognosis observed in the case of the left-sided malignancies [8].

RECIST 1.1 is an established instrument to assess a response to anticancer treatment based on radiologically determined cumulative diameter of target lesions. Cavitation of lung metastases assessed on CT scans at the baseline and at 8 weeks of regorafenib therapy seems to be a novel radiological predictor of PFS [9].
