A 59-year-old woman undergoes wide local excision of a 14 mm area of screen-detected high-grade DCIS with comedo necrosis. Margins exceed 10 mm and the sentinel node is negative. Which adjuvant measure has randomised evidence showing a substantial reduction in subsequent ipsilateral breast events?
- A Trastuzumab for one year
- B Adjuvant combination chemotherapy
- C Whole-breast radiotherapy ✓
- D Observation alone with annual mammography
Correct answer: C. Whole-breast radiotherapy
Explanation
Trials such as NSABP B-17 established that adding whole-breast irradiation after adequate excision of DCIS roughly halves the rate of local recurrence, both invasive and ductal carcinoma in situ. Chemotherapy has no role in pure DCIS and trastuzumab applies only to invasive HER2-positive disease. Tamoxifen modestly reduces recurrence and prevents contralateral tumours but does not replace radiotherapy, so observation alone would leave a substantially higher ipsilateral event rate.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.