The incidence of colorectal cancer ranks fourth worldwide after lung, prostate and breast cancers. Although chemotherapy has an important place in the treatment of colorectal cancers, it can cause side effects such as diarrhea and fatigue in patients. Cancer patients' ability to cope with treatment side effects can be benefited from technological developments. Studies have shown that mobile health applications reduce symptom experience and increase quality of life in patients with breast cancer and leukemia. This research was planned as a quasi-experimental study with a pre-test-post-test control group in order to examine the effects of the mobile health application developed according to the Self-Care Disability Theory and the training given for chemotherapy side effects on the quality of life of colorectal cancer patients. The sample of the study will consist of patients who underwent chemotherapy outpatient (23 intervention group and 23 control group) with the diagnosis of colorectal cancer in the Internal Medicine Medical Oncology outpatient clinic of Istanbul University-Cerrahpasa Cerrahpasa Medical Faculty. Simple random sampling method, which is one of the probabilistic sampling methods, will be used to determine the intervention and control groups. Data will be obtained (pre-test) with the Patient Information Form, the Self-Care Needs Assessment Form, the Nightingale Symptom Assessment Scale (N-SDS), and the Cancer Treatment Functional Assessment-Colorectal Scale (FACT-C). Training will be provided to the initiative group through the mobile health application. Symptom management and quality of life will be evaluated by using data collection tools after the 1st and 2nd cycles of chemotherapy in intervention group patients. A face-to-face meeting with the initiative group is planned every two weeks. Once a week, an message will be sent to the intervention group patients reminding them to use the mobile health application. Control group patients will continue to receive routine treatment and follow-up. A post-test will be applied to the intervention and control groups in the third month (12 weeks after the first interview). In this study, it is aimed to compare the effectiveness of routine treatment and care with the use of a mobile health application developed according to the Self-Care Insufficiency Theory, considering the developments in today's technology, and to evaluate the effects of the two methods on the control of symptoms that may occur due to chemotherapy side effects in colorectal cancer patients and their care needs.
