Acetylated Natural Nucleotides in Treating Hand-foot Syndrome

Inclusion Criteria: * 18 years of age or older. * Pathologically confirmed cancer receiving capecitabine-based anti-cancer therapy (capecitabine with or without other anti-cancer drugs). * With HFS determined by "CTCAE v5.0 - PPE" as grade 2 or above. * Able to use topical medications and complete questionnaires reliably with or without assistance. * ECOG performance score \< 2. Exclusion Criteria: * Has HFS due to other medications and does not recover within 4 weeks prior to baseline. * Other skin disorders that will affect efficacy evaluation on the hands and feet, including but not limited to: tinea of feet and hands, hand/foot eczema, palmoplantar pustulosis, palmoplantar keratosis, acrodermatitis continua etc. * Uncontrolled intercurrent illness as determined by the investigator including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, recent myocardial infarction, uncontrolled hypotension or hypertension, cardiac arrhythmia, or psychiatric illness and social situations that would limit compliance with study requirements. * Significantly abnormal lab test: * Inadequate hematologic function as indicated by: * Absolute neutrophil counts (ANC) \< 1,500 /mm\^3 * Hemoglobin (Hgb) \< 8.5 g/dL * Platelet count \< 75,000 /mm\^3 * PT or PTT \> 1.5 x ULN (if patients on anticoagulants: PT INR \> 3.5 x ULN) * Inadequate renal and liver function as indicated by: * Albumin \< 2.8 g/dL * Total bilirubin \> 1.5 x ULN (or \> 2.5 x ULN for patients with Gilbert's syndrome) * Aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase \> 2 x ULN * Creatinine \> 2 x ULN * Any other condition which, in the opinion of the Investigator, would impede compliance, hinder completion of the study, compromise the well-being of the patient, or interfere with the study outcomes.