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Study Comparing Serratus Plane Block, Capsaicin, and Botulinum Toxin Type A for Chronic Pain in Post-Mastectomy Patients

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on finding effective treatments for chronic neuropathic pain that occurs after a mastectomy, which is a surgery to remove one or both breasts, usually to treat breast cancer. The study is comparing three different treatments: a Serratus Plane Block (SPB), an 8% capsaicin patch, and Botulinum toxin type A. The purpose of the study is to evaluate how well these treatments can control pain that persists after initial treatments have not been successful.

Participants in the study will receive one of the three treatments and will be monitored over a period of time to assess the effectiveness of the treatment in reducing pain. The main assessment will take place 8 weeks after the treatment begins. During the study, participants will be asked to rate their pain levels using a simple scale from 0 to 10, where 0 means no pain and 10 means the worst pain imaginable. This self-assessment helps to understand how the treatment is working from the participant's perspective.

Throughout the study, additional evaluations will be conducted at various intervals to track changes in pain levels and any side effects that may occur. The study aims to provide valuable information on which treatment might be most effective for managing chronic pain after a mastectomy, offering hope for better pain management options in the future.

The research process

The trial runs in 8 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    Upon joining the study, an initial assessment is conducted to confirm eligibility. This includes verifying age, medical history, and current health status.

    Eligibility criteria include being a woman aged 18 or older, having undergone breast cancer surgery, and experiencing chronic neuropathic pain that persists after first-line treatment.

  2. Step 2

    Randomization

    Participants are randomly assigned to one of three treatment groups: serratus plane block (SPB), capsaicin patch, or botulinum toxin type A.

    This randomization ensures that each participant has an equal chance of receiving any of the treatments.

  3. Step 3

    Treatment administration

    The assigned treatment is administered according to the group allocation.

    For the SPB group, the treatment involves infiltration of the medication at the surgical site.

    The capsaicin group receives an 8% capsaicin patch applied topically.

    The botulinum toxin group receives an injection of the toxin at the affected area.

  4. Step 4

    Primary assessment

    The primary assessment of pain is conducted 8 weeks after treatment using the Numerical Pain Scale (NPS), which ranges from 0 to 10.

    If treatment fails before 8 weeks, the assessment may occur earlier.

  5. Step 5

    Secondary assessments

    Secondary assessments include evaluating pain control success, changes in pain levels, and the neuropathic component at 1, 2, 4, 6, 8, and 24 weeks after treatment.

    Additional assessments may occur at 13, 14, 16, and 18 weeks if treatment is repeated at 12 weeks.

  6. Step 6

    Adverse events monitoring

    Monitoring for adverse events related to the treatment is ongoing throughout the trial.

    Severe adverse events include significant pain, hematoma, or pneumothorax.

  7. Step 7

    Quality of life and psychological assessments

    Quality of life is assessed using the Health Related Quality of Life (SF-12) scale at baseline, 8 weeks, and 24 weeks.

    Psychological assessments using the HADS scale are conducted at the same intervals.

  8. Step 8

    Patient impression of change

    The Patient General Impression of Change (PGIC) scale is used to measure perceived changes in condition at 8 and 24 weeks.

    This self-assessment ranges from 1 (no change or worse) to 7 (considerable improvement).

Who can join the trial?

10 criteria

  • Women who are **18 years old or older**.
  • Have had **unilateral breast cancer** (cancer in one breast) treated with either a total or partial **mastectomy** (surgical removal of the breast). This could include:
    • Using a technique called **sentinel lymph node** (SLN) or **axillary dissection** (removal of lymph nodes in the armpit).
    • With or without immediate breast reconstruction using a **prosthesis** (artificial breast).
    • With or without additional treatments like **radiotherapy** (radiation treatment) and/or **chemotherapy** (cancer-fighting drugs).
    • Experience at least **moderate chronic neuropathic pain** (long-lasting nerve pain) defined by:
      • A **numerical rating scale** score of 3 or higher and a **DN4** score of 4 or higher. These are tools used to measure pain levels.
      • Pain located in a specific area (no larger than 240 square centimeters) at the surgical site, in the armpit, or on the inner side of the arm on the same side as the surgery.
      • Pain occurring between 3 and 9 months after breast surgery.
      • Pain that continues despite trying a first-line treatment for at least 4 weeks, which could include medications like **IRSNA**, **venlafaxine**, **gabapentin**, or **tricyclic antidepressants**, along with a **lidocaine patch** (a patch that numbs the area).
      • Must be **affiliated with a health insurance plan**.
      • Must be **informed about the trial** and agree to participate.

Who cannot join the trial?

3 criteria

  • Only women can participate in this study. Men are not eligible.
  • Participants must be within a specific age range. If you are not within this range, you cannot join the study.
  • The study is not open to vulnerable populations. This means people who might need special protection or care are not included.
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Investigated drugs

  • Serratus Plane Block (SPB)

    is a type of regional anesthesia technique used to manage pain. In this trial, it is being evaluated for its effectiveness in controlling chronic neuropathic pain in patients who have undergone a mastectomy. The procedure involves injecting a local anesthetic near the serratus anterior muscle to block pain signals.

  • Capsaicin

    is a compound derived from chili peppers, used in a patch form to relieve pain. In this trial, an 8% capsaicin patch is being tested for its ability to reduce chronic neuropathic pain in patients who have persistent pain after a mastectomy. The patch works by desensitizing pain receptors in the skin.

  • Botulinum toxin type A

    is a neurotoxin commonly known for its use in cosmetic procedures, but it also has applications in pain management. In this trial, it is being used to assess its effectiveness in reducing chronic neuropathic pain following a mastectomy. The toxin works by blocking nerve signals that cause muscles to contract, which can help alleviate pain.

What is already known about the treatment

  • Capsaicin

    Capsaicin is administered as an 8% patch applied directly to the skin. It is currently used in medicine for managing chronic neuropathic pain, particularly in conditions like post-mastectomy syndrome. The main therapeutic indication is to provide relief from persistent pain that does not respond to first-line treatments. Capsaicin works by affecting the TRPV1 receptor, which plays a role in pain sensation, leading to a decrease in pain signal transmission. It is classified as a topical analgesic.

  • Botulinum toxin type A

    Botulinum toxin type A is administered through injections into specific muscles or areas of the body. It is recognized in medical literature for its use in treating various types of pain, including chronic neuropathic pain associated with post-mastectomy syndrome. The primary therapeutic indication is to alleviate pain that remains after initial treatments have failed. Its mechanism of action involves blocking the release of certain neurotransmitters, which reduces muscle contractions and pain. It is classified as a neuromuscular blocker.

Investigated diseases

Chronic Neuropathic Pain of Post-Mastectomy Syndrome – This condition occurs after a mastectomy, which is a surgical procedure to remove one or both breasts, typically to treat or prevent breast cancer. It is characterized by persistent pain that is neuropathic in nature, meaning it arises from nerve damage or dysfunction. The pain can be felt in the chest, armpit, or arm area and may include sensations such as burning, tingling, or shooting pain. This type of pain can develop soon after surgery or may appear months later. It often persists despite initial treatments and can significantly affect a person's quality of life. The condition requires ongoing management to alleviate symptoms and improve daily functioning.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-517420-20-00Protocol codeSerCaBot-2302Estimated enrolment123 patientsSponsorCentre Oscar Lambret

sourced from the EU Clinical Trials Register and site verification

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