INSEMA Trial in Breast Cancer Journal Club Questions and Answers

Rodrigo Arrangoiz MS, MD, FACS, FSSO
  • What was the primary research question of the INSEMA trial?
    • Answer:
      • To determine whether sentinel lymph node biopsy (SLNB) can be safely omitted in patients with clinically node-negative early-stage breast cancer undergoing breast-conserving surgery and whole breast radiation, without compromising invasive disease-free survival (iDFS)
  • What type of study was this, and how was it designed?
    • Answer:
      • It was a prospective, randomized, multicenter, non-inferiority trial conducted in Germany and Austria
      • Patients were randomized in a 4:1 ratio to no SLNB vs. SLNB
  • What were the eligibility criteria for patients to be included in the trial?
    • Answer:
      • Female patients
      • Clinically node-negative (cN0) invasive breast cancer
      • Tumor size T1 to T2 (≤ 5 cm)
      • Candidates for breast-conserving surgery and whole-breast irradiation
      • No prior axillary surgery, neoadjuvant therapy, or mastectomy
  • What was the primary endpoint, and what was the non-inferiority margin?
    • Answer:
      • Primary endpoint:
        • 5-year invasive disease-free survival (iDFS)
      • Non-inferiority margin:
        • Hazard Ratio upper limit of 1.271 and ≥ 85% iDFS in the no-SLNB arm
  • What were the main results regarding iDFS
    • Answer:
      • iDFS: 91.9% (no-SLNB) vs. 91.7% (SLNB)
      • HR: 0.91 (95% CI, 0.73–1.14) → Non-inferiority was met
  • Was there a difference in overall survival (OS)
    • Answer:
      • Yes, but it favored no-SLNB slightly:
        • 5-year OS: 98.2% (no-SLNB) vs. 96.9% (SLNB):
          • Difference was not statistically significant
  • What was the axillary recurrence rate in both groups?
    • Answer:
      • No-SLNB: 1.0%
      • SLNB: 0.3%
        • While slightly higher in the no-SLNB group:
          • Both rates were very low and clinically acceptable
  • What secondary outcomes were assessed?
    • Answer:
      • Lymphedema incidence
      • Arm / shoulder function and pain
      • Quality of life
        • All significantly favored the no-SLNB group
  • What are the main clinical implications of this study?
    • Answer:
      • In selected low-risk patients:
        • SLNB may be safely omitted:
          • Reducing surgical morbidity and improving quality of life without compromising survival
  • Which subgroup of patients benefits most from SLNB omission based on this trial?
    • Answer:
      • Women ≥ 50 years old with T1, grade 1 to grade 2, hormone receptor-positive, HER2-negative tumors undergoing lumpectomy with whole breast radiation
  • Can we apply the findings of this trial to patients undergoing mastectomy or partial-breast irradiation?
    • Answer:
      • No:
        • Those patients were excluded, so the results cannot be extrapolated to those scenarios
  • How might omitting SLNB affect adjuvant therapy decisions?
    • Answer:
      • Without nodal staging, decisions about chemotherapy or genomic testing might become more challenging:
        • Multidisciplinary evaluation is essential
  • How do these findings compare to axillary de-escalation trends seen in trials like ACOSOG Z0011 or SOUND?
    • Answer:
      • Similar direction:
        • All support less axillary surgery in low-risk, clinically node-negative patients
      • INSEMA takes it a step further by testing omission of SLNB itself
  • What are some limitations of the INSEMA trial
    • Answer:
      • Limited generalizability:
        • Mostly postmenopausal, low-risk tumors
      • Exclusion of higher-risk patients:
        • HER2+, triple-negative, T2 > 3 cm
      • Lack of data in mastectomy or neoadjuvant settings
  • If one of your patients meets criteria from this trial, how would you counsel them on omitting SLNB?
    • Answer:
      • Explain that in select low-risk early-stage breast cancer, omitting SLNB does not affect survival, reduces the risk of complications like lymphedema, and improves quality of life:
        • However, thorough discussion with oncology and radiation teams is important to individualize care
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Published by Rodrigo Arrangoiz MS, MD, FACS, FSSO

My name is Rodrigo Arrangoiz I am a breast surgeon/ thyroid surgeon / parathyroid surgeon / head and neck surgeon / surgical oncologist that works at Center for Advanced Surgical Oncology in Miami, Florida. I was trained as a surgeon at Michigan State University from (2005 to 2010) where I was a chief resident in 2010. My surgical oncology and head and neck training was performed at the Fox Chase Cancer Center in Philadelphia from 2010 to 2012. At the same time I underwent a masters in science (Clinical research for health professionals) at the University of Drexel. Through the International Federation of Head and Neck Societies / Memorial Sloan Kettering Cancer Center I performed a two year head and neck surgery and oncology / endocrine fellowship that ended in 2016. Mi nombre es Rodrigo Arrangoiz, soy cirujano oncólogo / cirujano de tumores de cabeza y cuello / cirujano endocrino que trabaja Center for Advanced Surgical Oncology en Miami, Florida. Fui entrenado como cirujano en Michigan State University (2005 a 2010 ) donde fui jefe de residentes en 2010. Mi formación en oncología quirúrgica y e n tumores de cabeza y cuello se realizó en el Fox Chase Cancer Center en Filadelfia de 2010 a 2012. Al mismo tiempo, me sometí a una maestría en ciencias (investigación clínica para profesionales de la salud) en la Universidad de Drexel. A través de la Federación Internacional de Sociedades de Cabeza y Cuello / Memorial Sloan Kettering Cancer Center realicé una sub especialidad en cirugía de cabeza y cuello / cirugia endocrina de dos años que terminó en 2016.

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