Table 2 Biological and clinical data suggesting a possible role of rechallenge in management of mCRC

Role of rechallenge in mCRC

K-ras status concordance and heterogeneity

K-ras mutation is an early pathogenic step in colorectal cancer development and the possibility of late acquisition of K-Ras mutation is not clarified. The following therapy could allow K-Ras WT clone to re-predominate

Treatment holiday

Holiday from a drug could allow reversion to a previous epigenetic profile. Moreover treatment holiday could facilitate recovery from cumulative toxicity induced by chemotherapy. To our knowledge few studies evaluated role of treatment holiday and they reported results.