3. First-line application of fluorouracil-based chemotherapy failed (treatment failure definition: toxic side effects can not tolerate the progress of the disease during treatment or recurrence after treatment); Note:(1) Time of first-line treatment for subjects with advanced tumour must more than 1 cycles;(2) Adjuvant/neoadjuvant therapy was allowed; adjuvant/neoadjuvant therapy will be considered as a first-line treatment if disease recurrence during treatment or after less than 24 weeks.