Inclusion Criteria:
* Participant must have histologically proven invasive breast cancer that is HR (hormone receptor) positive and HER2 (Human Epidermal Growth Factor Receptor 2) negative according to the 2010 American Society of Clinical Oncology (ASCO) College of American Pathologists (CAP) guidelines (ER and/or PR (progesterone receptor) \>1% and HER2 negative by immunohistochemistry \[IHC\] and/or fluorescent in situ hybridization \[FISH\]).
* Participant must have early-stage operable disease (stage I-II or III who have planned upfront surgery) and agree to definitive upfront surgery.
* Participant must be available for at least two weeks of TheraBionic treatment prior to scheduled resection
* Participant must have archival tissue available.
* Participant must be a woman aged 22 years or older
* Participant must be able to understand a written informed consent document and be willing to sign it
* Participant must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2.
* It is not known what effects this treatment has on human pregnancy or development of the embryo or fetus. Therefore, women of child-bearing potential must agree to avoid becoming pregnant starting at initiation of treatment up until at least 30 days after the last TheraBionic P1 session
Exclusion Criteria:
* Participants that are receiving or will receive neoadjuvant chemotherapy or neoadjuvant hormonal therapy
* Participants with known active secondary malignancy, unless, in the opinion of the investigator, it is unlikely to interfere with the safety and efficacy of the endpoints
* Participants that are taking any other investigational drugs
* Participants that are pregnant or breastfeeding due to the unknown but potential risk for adverse events. If a breastfeeding participant would like to be part of this study, breastfeeding must be discontinued
* Participants with active oral mucosal inflammation, ulceration, or other pathology that could interfere with the use of TheraBionic P1 device (for example: mucositis, thrush, bleeding mucosal lesions, oral herpes, aphthous stomatitis, mouth ulcers, chancre sores, gingivostomatitis, herpangina, aphthae).
* Participants receiving calcium channel blockers and any agent blocking L-type or T-type voltage gated calcium channels (for example: amlodipine, nifedipine, ethosuximide, ascorbic acid/vitamin C, etc.) unless their medical treatment is discontinued at least one day prior to treatment. Participant must agree to abstain from using calcium channel blockers for the duration of treatment on study.
* Participants that do not agree to be followed according to the study protocol or have cognitive or physical inability to use the device
