Wearable Activity Tracking to Curb Hospitalizations

Inclusion Criteria:

* Age \>= 18.
* Eastern Cooperative Oncology Group (ECOG) performance status =\< 2 or Karnofsky Performance Scale (KPS) \>= 50%.
* Able to understand study procedures and to comply with them for the entire length of the study.
* Ability of individual or legal guardian/representative to understand a written informed consent document, and the willingness to sign it.
* Diagnosis of invasive malignancy.
* Able to ambulate independently (without the assistance of a cane or walker).
* Planned treatment with fractionated external beam radiotherapy over at least 5 days (no fractional requirement).
* Not a previous participant on this protocol for subsequent courses.

Exclusion Criteria:

* Participants bound to a wheelchair.
* Participants unable to ambulate independently (needing assistance of cane or walker).