Background: Radioactive iodine treatment (RAIT) is an essential therapy for differentiated thyroid cancer. However, unforeseen complications arising during thyroid hormone withdrawal (THW) can lead to Cancellation of the scheduled treatment. This study aimed to identify cases in which THW-RAIT was discontinued due to THW-related complications and to explore potentially preventable causes to improve patient management. Methods: Among 4,174 patients who underwent THW-RAIT between 2012 and 2024, 39 did not complete the planned treatment. After excluding Cancellations unrelated to THW, 11 (0.26%) patients with unexpected THW-related medical issues were analyzed. Results: The median age of the included patients was 61 years (range, 23 to 70), and 10 were male. The reasons for THW-RAIT Cancellation were hyponatremia (n=1), abnormal liver function (n=1), renal dysfunction (n=3), and combined liver and renal dysfunction (n=6). The patient with hyponatremia was taking a thiazide diuretic. Most cases of liver dysfunction were associated with prior use of herbal medications, whereas renal dysfunction was linked to diuretic or nonsteroidal anti-inflammatory drug use, pre-existing conditions such as single kidney or diabetic nephropathy, or inadequate oral intake during low-iodine preparation. Two cases of concurrent liver and renal dysfunction were attributed to rhabdomyolysis following intense exercise or heavy physical labor. Conclusion Enhanced patient education, comprehensive pre-treatment assessment, and careful avoidance of high-risk medications are essential to prevent THW-related complications and minimize disruptions in RAIT.

Colorectal cancer is the third most common cancer in Korea and the third leading cause of death from cancer. Treatment outcomes for colon cancer are steadily improving due to national health screening programs with advances in diagnostic methods, surgical techniques, and therapeutic agents.. The Korea Colon Cancer Multidisciplinary (KCCM) Committee intends to provide professionals who treat colon cancer with the most up-to-date, evidence-based practice guidelines to improve outcomes and help them make decisions that reflect their patients’ values and preferences. These guidelines have been established by consensus reached by the KCCM Guideline Committee based on a systematic literature review and evidence synthesis and by considering the national health insurance system in real clinical practice settings. Each recommendation is presented with a recommendation strength and level of evidence based on the consensus of the committee.