Digital vs conventional glycemic monitoring in rare endocrine cancers: comparison of effectiveness during chemotherapy

Aims: Chemotherapy regimens can induce severe hyperglycemia, which may be underestimated using conventional point-of-care blood glucose (POC-G) measurement techniques. Real-time continuous glucose monitoring (rtCGM) systems may offer a more accurate assessment of glucose metabolism. In this study, we compared blood glucose monitoring using POC-G and rtCGM in patients with rare endocrine cancers caused by chemotherapy and steroid medication. Methods: In this single-center observational study, we analyzed data from 76 hospitalized patients with pancreatic neuroendocrine tumors (n = 48) or adrenocortical carcinoma (n = 28) undergoing chemotherapy. Patients were monitored using either POC-G (n = 38) or rtCGM (n = 38). Glycemic metrics included time in range (TIR), prevalence of steroid-induced hyperglycemia (SIH), and HbA1c. Results: Using POC-G, TIR was 23.6 ± 0.9 h/day in patients without diabetes (NoD) and 20.0 ± 4.2 h/day in patients with diabetes undergoing chemotherapy (mean: five cycles). However, when rtCGM was used, drastic changes in TIR were documented under the same regimen. The mean TIR decreased from 21.7 h/day in patients with NoD to 14.6 h/day in patients with diabetes (P < 0.01). Similarly, the overall incidence of SIH was 30% using conventional POC monitoring, but this figure rose to 79% using rtCGM. During rtCGM use, HbA1c decreased by 0.3% over the course of the chemotherapy cycles, whereas during POC-G use, HbA1c increased by 0.2% (P < 0.01). Conclusion: We demonstrated a previously underestimated frequency of hyperglycemia and SIH in patients undergoing chemotherapy by using rtCGM. The use of rtCGM enabled more detailed recognition of dysglycemia and may improve glucose metabolism during and after chemotherapy regimens.