The purpose of this study was to identify the state of self-management in patients with diabetes who underwent chemotherapy, by referring to fluctuations in glycemic excursion and adverse drug reaction. We conducted a literature search in May 2021 using PubMed, CINAHL, and Ichushi-Web databases with “Cancer AND Diabetes AND Chemotherapy” as keywords. Based on our criteria, 25 articles were selected, and a review matrix sheet was created for the analysis of fluctuations in glycemic excursion and any adverse drug reaction to diabetes in patients undergoing chemotherapy. Substantial increases and unpredictable fluctuations in glycemic excursion were observed in these patients. In addition, an increase or change in the treatment dose was prevalent. Primarily, peripheral neuropathy and infection were reported as common adverse drug reactions. The risk of adverse drug reactions was especially high for patients with diabetes undergoing chemotherapy; furthermore, among this cohort, the detrimental effects were more likely to exacerbate into a severe condition that required special attention. Almost inevitably, the implementation rate of diabetes self-management programs decreased on the 8
th
week after the commencement of chemotherapy. Considering the findings of large individual differences in fluctuation in this cohort, tailored assistance that is appropriate for each patient's chemotherapy regimen or blood glucose level is of paramount importance. Support of patient self-management to achieve stable blood glucose levels and thus prevent adverse drug reactions was a key component in the successful completion of chemotherapy and improved patient outcomes for this group of special needs patients.