2.4. Recruitment
We will recruit 160 participants scheduled to receive multi-agent chemotherapy regimens with intensively myleosuppressive agents on day 1 (mFOLFIRINOX, ECb, EP, FOLFOX, FOLFIRI) as an adjuvant/neoadjuvant or first-line palliative treatment in 5 Korean academic hospitals (Pusan national university yangsan hospital, Hanyang University Seoul Hospital, Dong-A University hospital, Haeundae Paik Hospital, Kosin University Gospel Hospital) (Fig. 