2. Documented disease progression (with radiographic or clinical evidence) during or within 16 weeks after chemotherapy containing first-line treatment; subjects must receive at least one dosage of first-line treatment, treatment termination, dose reduction of one drug or replacement among fluorouracil drugs is acceptable, treatment termination due to intolerable toxicity is not included; for neoadjuvant or adjuvant chemotherapy/chemoradiotherapy, if disease progression occurs during or within 6 months after treatment, it should be considered as first-line therapy