A 54-year-old woman undergoes wide local excision with clear margins for a 15 mm area of intermediate-grade pure DCIS detected on screening mammography. Sentinel nodes are negative. What is the principal proven benefit of adding whole-breast radiotherapy in this setting?

• A It improves overall survival compared with excision alone
• B It approximately halves the rate of ipsilateral breast tumour recurrence ✓
• C It converts DCIS into a lesion requiring no further surveillance
• D It eliminates the need for long-term endocrine therapy

Explanation

Randomised evidence including NSABP B-17 and the EBCTCG overview shows that radiotherapy after clear-margin excision of DCIS substantially reduces ipsilateral in-breast recurrence, roughly halving it, but produces no measurable overall survival benefit because recurrences are salvageable. This is why some low-risk patients are offered excision alone. Radiotherapy does not remove the need for mammographic surveillance, and endocrine agents such as tamoxifen act independently on hormone receptor-positive disease rather than being replaced by radiation.

Reference: Bailey and Love's Short Practice of Surgery, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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