Botulinum Toxin A (Botox) in Tissue Expander Breast Reconstruction


  • Study type

  • Study phase

  • Study IDs

  • Describes the nature of a clinical study. Types include:

    • Observational study — observes people and measures outcomes without affecting results.
    • Interventional study (clinical trial) — studies new tests, treatments, drugs, surgical procedures or devices.
    • Medical records research — uses historical information collected from medical records of large groups of people to study how diseases progress and which treatments and surgeries work best.
  • During the early phases (phases 1 and 2), researchers assess safety, side effects, optimal dosages and risks/benefits. In the later phase (phase 3), researchers study whether the treatment works better than the current standard therapy. They also compare the safety of the new treatment with that of current treatments. Phase 3 trials include large numbers of people to make sure that the result is valid. There are also less common very early (phase 0) and later (phase 4) phases. Phase 0 trials are small trials that help researchers decide if a new agent should be tested in a phase 1 trial. Phase 4 trials look at long-term safety and effectiveness, after a new treatment has been approved and is on the market.

  • Site IRB
    • Rochester, Minnesota: 11-001687
    NCT ID: NCT01591746
    Sponsor Protocol Number: 11-001687

About this study

Each year, the number of breast cancer survivors who choose post-mastectomy breast reconstruction keeps rising. Among women who elect to pursue breast reconstruction, approximately 75% will choose prosthetic breast reconstruction. Implant-based breast reconstruction is frequently achieved in two-stages. The first stage consists of the placement of a tissue expander after mastectomy. This is followed by a period of weekly tissue expansions that can last several months. In the second stage, the tissue expander is removed in a surgical procedure and replaced with a permanent breast implant. Tissue expansion is a well-established breast reconstruction technique characterized by high success rates and high patient satisfaction. Despite the well-recognized advantages of this successful breast reconstruction technique, the subpectoral placement of a tissue expander is associated with significant pain and discomfort in the immediate post-operative period and during the phase of tissue expansion. Pectoralis major muscle spasm is a frequently reported problem during tissue expansion. Legeby et al. recently showed that women who underwent prosthetic breast reconstruction had higher pain scores and took more analgesics that those who did not choose post-mastectomy reconstruction.

In the past 10 years, publications on the use of BTX-A for pain relief in a wide array of clinical conditions have increased tremendously. BTX-A is one of the neurotoxins produced by Clostridium botulinum bacteria. By reversibly inhibiting neurotransmitter release, BTX-A has both analgesic and paralytic properties. The analgesic action of BTX-A was initially thought to be related to its effects on muscular contraction. However, a recent in vitro study of embryonic rat dorsal neurons did confirm that BTX-A inhibits release of substance P, a neurotransmitter associated with pain and inflammatory reactions. The presence of analgesic properties of BTX-A is increasingly supported by several clinical observations: pain relief with BTX-A injections has been reported for migraine headaches, chronic pelvic, chronic tennis elbow, and post-operative pain control for lower limb lengthening correction, among others.

This aspect has never been studied in breast cancer survivors who elect to pursue breast reconstruction with tissue expanders. Furthermore, physical function outcomes are important to consider with BTX-A use because the link between temporary muscle paralysis and improvements in participation in daily activities is not a given.

The investigators propose to complete a double-blinded prospective randomized controlled trial of women undergoing unilateral and bilateral mastectomies with immediate placement of tissue expanders, to establish the efficacy and safety of BTX-A in alleviating pain and in improving physical well-being during the expansion period.

Participation eligibility

Participant eligibility includes age, gender, type and stage of disease, and previous treatments or health concerns. Guidelines differ from study to study, and identify who can or cannot participate. If you need assistance understanding the eligibility criteria, please contact the study team.

See eligibility criteria


  1. Women at least 18 years of age, who will undergo immediate unilateral or bilateral tissue expander breast reconstruction following therapeutic skin-sparing or nipple-sparing mastectomy.
  2. Women at least 18 years of age, who will undergo immediate bilateral tissue expanders breast reconstruction following risk-reduction (prophylactic) skin-sparing or nipple-sparing mastectomy.


  1. Subjects who are unable to read or speak English.
  2. Breast reconstruction using the latissimus dorsi flap combined with a tissue expander.
  3. Documented diagnosis of chronic pain, upper limb spasticity, cervical dystonia, axillary hyperhidrosis, strabismus or blepharospasm;
  4. Hypersensitivity to any botulinum toxin preparation or to any of the components in the formulation.
  5. Infection at the proposed site of injection.
  6. Pre-existing neuromuscular disorders (including diagnosed myasthenia gravis, Eaton-Lambert syndrome, or amyotrophic lateral sclerosis).
  7. Aminoglycosides intake at the time of surgery (these antibiotics can potentiate the effect of BTX-A).
  8. Women who are pregnant or breast feeding.
  9. Presence of submuscular implants from previous breast surgery.
  10. Reported use of Botox within 4 months prior to planned surgical date.

Participating Mayo Clinic locations

Study statuses change often. Please contact us for help.

Mayo Clinic Location Status Contact

Rochester, Minn.

Mayo Clinic principal investigator

Nho Tran, M.D.

Closed for enrollment

Contact information:

Sheri Ramaker R.N.



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