Ductal Carcinoma In Situ (DCIS) Radiation Oncology Perspective Part 2

Rodrigo Arrangoiz MS, MD, FACS, FSSO
  • The second generation trials in DCIS:
    • Started to think if there is a sub group of patients that we can omit radiation therapy
  • This trials looked into high risk factors for local regional recurrence (LRR) in DCIS:
    • Prognostic factors associated with increased locoregional recurrence:
      • Age less than 50 years
      • Size > than 2 cm
      • Grade 3
      • Positive of close < margins
    • Additional risk factors:
      • Symptomatic:
        • Palpable / bloody discharge
      • Comedo, solid types of DCIS
      • Black race
      • ER and / or PR negative
  • What is the optimal surgical margin in DCIS?
  • The use of a 2-mm margin as the standard for an adequate margin in DCIS treated with whole-breast irra- diation is associated with lower rates of IBTR and has the potential to decrease re-excision rates, improve cosmetic outcomes, and decrease health care costs:
    • Clinical judg- ment should be used in determining the need for further surgery in patients with negative margins narrower than 2 mm.
  • The second generation DCIS trials:
    • RTOG 9804:
      • They included:
        • Mammographically detected DCIS
        • Low to intermediate-grade DCIS
        • Less than 2.5 cm
        • Margins =/> than 3 mm
      • This study has two different perspectives:
        • Although the results are significant:
          • Local recurrence (LR) rates without RT are less than 10%
Longer follow-up of the RTOG 9804 trial: LR rates were as high as 15.1% in omitted radiation arm
  • The second generation DCIS trials:
    • ECOG E5194:
      • From 1997 to 2022:
        • Has only one arm
      • Inclusion criteria:
        • Non-palpable DCIS
        • Cohort 1:
          • Low to intermediate grade DCIS < than 2 cm
        • Cohort 2:
          • High grade DCIS < than 1 cm
        • > 3 mm margins / no residual calcifications on postoperative mammogram
        • Lumpectomy alone:
          • NO radiation
        • Starting in the year 2000:
          • Patients could take tamoxifen
Like in the RTOG 9804 trial patients in the ECOG E5194 trial tended to be older, postmenopausal, have wider margins of resection, and had smaller tumors (detected on mammogram).
With long-term follow-up in the ECOG E5194 the LR rates in high risk DCIS were almost 25% and in lower risk DCIS was 14.4%, but local control rates were still high and these data should be taken into account in share decision making.
  • What can we use to help us determine risk of recurrence in DCIS?
    • Genomic Assays – DCISion RT (Prelude DX):
      • Seven gene biological risk signature developed from three cohorts:
        • UCSF (n=324)
        • Uppsala Univeristy Hospital, Sweden (n=458)
        • University of Massachusetts (n=300)
      • Decision score 0 to 10:
        • Low risk 0 to 3
        • High risk score > 3 to 10
      • This biological signature was validated in a retrospective cohort
The patients that were defined as low risk by clinical and pathological factors were could actually be higher risk patients based on genetic analysis in 41% to 49% of the cases. 34% to 36% of high risk DCIS patients were found to be low risk by DCISion RT.
  • This tool is available but it has not be validated in a prospective clinical trial
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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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