Ductal Carcinoma In Situ (DCIS) Radiation Oncology Perspective Part 1

Rodrigo Arrangoiz MS, MD, FACS, FSSO
  • Goals of radiation for DCIS:
    • Prevent local recurrence:
      • Both DCIS and invasive
    • Avoid mastectomy
    • Minimum toxicity
  • Seminal first generation trials of radiation therapy after breast conserving surgery (BCS) for DCIS:
Meta-Analysis of DCIS Trials. These trials showed that radiation therapy in DICS significantly decreased local recurrence rates of both DCIS and IBC.
  • Radiation therapy is associated with a roughly 50% relative risk reduction in local recurrence and absolute risk reduction of 15%:
    • In these studies most patients did not receive tamoxifen
  • The first generation seminal trials:
    • Were conducted in the 1980’s and 1990’s
      • Many patients had symptomatic DCIS:
        • With palpable tumors of bloody nipple discharge:
          • Screening mammogram was uncommon
      • 10% to 20% of patients had a positive or close margins
      • Greater than 1/3 of the patients had high grade DCIS
  • The DCIS patients that we see in our clinics today are:
    • Smaller, low grade, and are diagnosed earlier:
      • Because of the screening mammograms
  • The effect of tamoxifen on local control:
NSABP B 24. Lumpectomy + RT vs. Lumpectomy + RT + Tamoxifen. A. Estrogen receptor negative patients B. Estrogen receptor positive patients
  • In the NSABP B 24 trial in multivariable analysis:
    • Young age and no tamoxifen were adverse prognostic factors
  • Long-term outcomes of invasive ipsilateral breast cancer recurrences after lumpectomy in the NSABP B-17 and B-24 randomized trials for DCIS:
The cumulative analysis of these trials showed that radiation therapy has a relatively greater impact on preventing local recurrence than tamoxifen. Tamoxifen plays a role in significantly decreasing the risk of contralateral breast cancer.
  • Anastrozole vs Tamoxifen in DCIS (IBIS-II DCIS Trial):
    • 2980 postmenopausal women
    • 71% of the patients received radiation therapy
    • Randomization:
      • Anastrozole vs tamoxifen
    • Median follow-up:
      • 7.2 years
    • 144 breast cancer recurrences
    • The non-inferiority of anastrozole was established:
      • But its superiority to tamoxifen was not
    • Adverse effects:
      • Anastrozole:
        • More fractures, musculoskeletal events, hypercholesterolemia, and strokes
      • Tamoxifen:
        • More muscle spasms, gynecological cancers and symptoms, vasomotor symptoms, and deep vein thromboses
  • NSABP B-35 Trial
  • Summary of radiation therapy in DCIS:
    • If prevention of ipsilateral breast tumor recurrence (IBTR) is the primary goal:
      • Tamoxifen cannot replace the impact of radiation therapy on local control after BCS
    • Tamoxifen may further decrease local regional recurrence risk after BCS therapy with radiation and significantly reduce contralateral breast cancer
    • In postmenopausal women less than 60 years of age:
      • Anastrozole may be more effective than tamoxifen
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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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