Evaluation of the Effectiveness of Managing Chemotherapy Side Effects Using ePRO and a Standardized Telenursing Program for Cancer Patients

Inclusion Criteria: * Adults aged 19 years or older * Diagnosed with early or advanced gastric, lung, breast, or colon cancer * Starting first-cycle chemotherapy with a new anticancer agent * Able to use a smartphone without difficulty * Willing to provide informed consent to participate in the study Exclusion Criteria: * Individuals who have difficulty communicating due to cognitive impairment, visual impairment, hearing impairment, or other reasons * Individuals who cannot read, write, or understand Korean * Other individuals deemed inappropriate for participation by the investigators