Use of a Comprehensive, Mobile Application to Assist Cancer Patients With Diet, Nutrition and Activity

Inclusion Criteria:

* Diagnosis of invasive malignancy of the brain, head and neck region, lung, breast (DCIS and invasive disease allowed), prostate, gastrointestinal system or gynecological region
* Planned to receive, or have received, radiation therapy treatment with curative intent

  * Note: Patients undergoing systemic therapy are eligible
  * Note: Any dose/fractionation of curative-intent radiation therapy is eligible
* Patients must have a smartphone or other device with the ability to receive text messages, download and use mobile applications
* Eastern Cooperative Oncology Group (ECOG) performance status 0-2
* Ability to read and write in English
* Provide written informed consent to participate in the study o NOTE: Patients enrolled on another clinical trial are eligible

Exclusion Criteria:

* Metastatic cancer
* Undergoing treatment with palliative intent
* Poorly controlled diabetes (defined as fasting glucose level \> 200 mg/dL despite attempts to improve glucose control by fasting duration and adjustment of medications)
* Uncontrolled hypertension
* Any medical condition requiring fluid restriction or nutrient restrictions