Dose Adaptation of Capecitabine Using Mobile Phone Toxicity Monitoring

Patients with metastatic colorectal or breast cancer will be recruited. * Metastatic Colorectal Cancer: capecitabine alone or capecitabine + oxaliplatin for 8 3-week cycles * Metastatic Breast Cancer: capecitabine alone or capecitabine + docetaxel for 8 3-week cycles. All patients will be given a mobile phone onto which they will enter any side-effects experienced prior to taking capecitabine in the morning and evening. Any grade 3 or 4 symptoms will trigger an alert to a pager held by the ward-staff for immediate attention. Thus, patients' severe side-effects will be monitored in real time and the trial will allow real-time dose reductions during cycles and dose-increases at clinics. Patient experience in the trial will also be evaluated during their participation in the trial. Patients will already be receiving the drug prior to this study and will not be administered to patients as part of this study.