Recruiting
Phase 2

Microbiome

Sponsor:

UCLA

Code:

NCT05020574

Conditions

Breast Cancer

Breast Cancer Female

Genetic Predisposition to Disease

Eligibility Criteria

Sex: Female

Age: 18+

Healthy Volunteers: Not accepted

Interventions

Cephalexin

Study Details

Brief summary:

The most common tissue expander-related infections are from Staphylococcus and Pseudomonas species. In addition, from breast tissue microbiome studies, Staphylococcus and Pseudomonas show variable abundance across samples. The investigator hypothesizes that participants undergoing mastectomy with high initial abundance of Staphylococcus and/or Pseudomonas are more likely to develop subsequent tissue expander-related infections from these respective organisms.

Conditions

Breast Cancer

Breast Cancer Female

Genetic Predisposition to Disease

Study ID

NCT05020574

Start date

Sep 28, 2021

Status verified date

Mar, 2026

Completion date

Dec 31, 2026

Anticipated

Primary completion date

Dec 31, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: Female

Age: 18+

Healthy Volunteers: Not accepted

Inclusion Criteria:

1. Patients must have histologically confirmed breast malignancy OR genetic predisposition to breast cancer.
2. Age >= 18 years
3. Scheduled to undergo mastectomy with the immediate placement of tissue expanders or implant placement
4. Ability to understand a written informed consent document, and the willingness to sign it
5. At least 4 weeks post-completion of chemotherapy or radiation therapy.

Exclusion Criteria:

1. Any significant medical condition or laboratory abnormalities, which places the subject at unacceptable risk if he/she were to participate in the study
2. Pregnant or breastfeeding
3. Patients who have taken antibiotics within 90 days of the consent date
4. Patients who have taken probiotics within 90 days of the consent date
5. Patients who have a documented or reported allergic reaction to the outlined antibiotics to be used in this study
6. Male patients

Study Design

Enrollment

200 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Supportive Care

Interventions and Outcome Measures

Arms

experimental: Cohort A: Standard antibiotics

Receive standard pre-incision antibiotics and 24-hour perioperative antibiotics - Prescribed standard postoperative antibiotics to take for at least 7 days post-operatively

no intervention: Cohort B: No antibiotics

Receive standard pre-incision antibiotics and 24-hour perioperative antibiotics - No antibiotics post-operatively, unless patient develops clinical evidence of infection

Interventions

Cephalexin

Given orally (PO)

Primary outcome measure

  • Proportion of tissue samples obtained successfully over time [ Time Frame: 90 days ]
  • Proportion of aspirate samples obtained successfully overall [ Time Frame: 90 days ]
  • Proportion of tissue samples successfully producing microbiome data [ Time Frame: 90 days ]
  • Proportion of aspirate samples successfully producing microbiome data [ Time Frame: 90 days ]
  • Proportion of any samples successfully producing microbiome data [ Time Frame: 90 days ]
  • Correlation of the change in breast microbiome over time with total duration of antibiotics (Cohort A only) [ Time Frame: 90 days ]

Central Contacts and Locations

Central contacts

Laura Barnes, MD

(415) 502-1259Laura.Barnes@ucsf.edu

Locations

University of California, San Francisco

Recruiting

San Francisco, California, United States, 94143

Contacts

Laura Barnes, MD

415-502-1259Laura.Barnes@ucsf.edu

877-827-3222cancertrials@ucsf.edu

Principal Investigator:

Merisa Piper, MD

More Information

Sponsor

University of California, San Francisco

Last update posted

Mar 18, 2026

Last verified

Mar, 2026

Keywords

  • Post-Surgical Antibiotics
  • Breast Implant Infections
  • Breast Microbiome
  • Breast Reconstruction
  • Mastectomy

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by University of California, San Francisco on 2026-03-18.