Botulinum Toxin A (Botox) in Tissue Expander Breast Reconstruction
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 in 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.
Drug: Botulinum Toxin Type A
Drug: Sodium Chloride Solution
|Study Design:||Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
Primary Purpose: Supportive Care
|Official Title:||Botulinum Toxin A in Tissue Expander Breast Reconstruction: A Double-Blinded Randomized Controlled Trial|
- Change from Baseline in average pain scores using a numeric pain intensity scale [ Time Frame: Pre-operatively, post-opeartively: at 1 week, 2 weeks, at every expansion, at 3 months, and at the follow-up visit prior to the second surgery ] [ Designated as safety issue: No ]The numeric pain intensity scale (NPIS) will be completed at various time frames. The NPIS is a visual analog scale commonly used to assess clinical pain.
- Change from Baseline in Physical Well-Being using the BREAST-Q Physical Well-Being scale [ Time Frame: Pre-operatively, post-opeartively: at 1 week, 2 weeks, at every expansion, at 3 months, and at the follow-up visit prior to the second surgery ] [ Designated as safety issue: No ]The Physical Well-Being scale of the BREAST-Q, reconstruction module, will be used for this purpose. The BREAST-Q is a validated patient-reported outcome measure to accurately assess quality of life and patient satisfaction.
- Initial percent volume expansion intra-operatively [ Time Frame: Single intra-operative measurement at first surgery ] [ Designated as safety issue: No ]The amount of initial intraoperative fill volume in the tissue expander at the time of surgery divided by the manufacturers recommended total tissue expander volume will be measured.
- Rate of tissue expansion [ Time Frame: Up to 24 weeks ] [ Designated as safety issue: No ]Measurement of expansion volume at each tissue expansion and number of tissue expansions completed.
- Rate of reconstruction failure [ Time Frame: At 6 months after first surgery ] [ Designated as safety issue: Yes ]Determine the rate of tissue expander removal.
- Incidence of side effects attributable to the injection of BTX-A at doses of 100 units and 200 units. [ Time Frame: First 30 days postoperatively ] [ Designated as safety issue: Yes ]All serious adverse events will be recorded and reported. Minor adverse events and unusual complications encountered during the postoperative period will be carefully recorded.
|Study Start Date:||August 2012|
|Estimated Study Completion Date:||August 2015|
|Estimated Primary Completion Date:||August 2015 (Final data collection date for primary outcome measure)|
Experimental: Group A
Botulinum Toxin A
Drug: Botulinum Toxin Type A
100 Units of Botulinum toxin A diluted in 5 mL 0.9% Sodium Chloride in the pectoralis major muscle in each operated breast.
Other Name: BOTOX
Placebo Comparator: Group B
Drug: Sodium Chloride Solution
5 mL 0.9% NaCl injection to the pectoralis major muscle in each operated breast.
Consecutively enrolled eligible women will be randomized into one of two different treatment groups: 1) Group receiving BTX-A, and 2) Group receiving a placebo. All consenting subjects will be assigned to receive during surgery either a single injection of 100 units of BTX-A, or a placebo (saline water), in the pectoralis major muscle on the operated side once the mastectomy and the breast reconstruction have been completed. Expected duration of subject participation is up to 12 months, depending on the number of tissue expansion visits necessary to fill the tissue expander to its final desired volume.
|Contact: Valerie Lemaine, MDfirstname.lastname@example.org|
|United States, Minnesota|
|Rochester, Minnesota, United States, 55905|
|Contact: Valerie Lemaine, MD, MPH email@example.com|
|Principal Investigator:||Valerie Lemaine, MD||Mayo Clinic|