Extensive high-grade DCIS on core biopsy — upgrade consent, 2 mm margins, sentinel-node choice, radiotherapy and endocrine plan

Model answer

(A) Upgrade consent and surgical plan (4 marks)

• Quote the upgrade rule before anything else: about one in four core-biopsy DCIS diagnoses (25.9% pooled) prove invasive at excision — and her lesion carries nearly every predictor: 14-gauge sampling, high grade, 28 mm span, palpable thickening.^[10]
• Plan complete excision to the 2 mm standard with whole-breast irradiation in view: negative margins halve recurrence against ink on DCIS, 2 mm minimises it, wider clearance adds nothing — while under-2 mm negativity alone never mandates mastectomy.^[9]
• Sentinel-node decision follows the operation, not the anxiety: with planned conservation, no sentinel surgery (ASCO reserves it for mastectomy); if extent forces mastectomy, stage the axilla at the same operation because the window closes.^[11]
• Her 28 mm span makes mastectomy a legitimate branch of the same consent — size predicts both mastectomy and upstaging — with clip placement, imaging-pathology correlation and multidisciplinary review either way.^[9][10]

(B) Radiotherapy and endocrine evidence (3 marks)

• Radiotherapy: B-17 cut invasive ipsilateral tumours from 13.4 to 3.9% with lumpectomy plus 50 Gy, all subgroups benefiting; EORTC at 15 years lifted recurrence-free 69 to 82% — with no survival difference (BCSS HR 1.07, OS HR 1.02), so consent local control, not rescue.^[1][4]
• Endocrine therapy: B-24 (tamoxifen 20 mg daily for 5 years with lumpectomy plus radiation) cut 5-year events 8.2 versus 13.4%, holding even with involved margins and comedonecrosis; UK/ANZ confirms fewer local and contralateral events with the same 20 mg dose.^[2][5]
• Name the limit both halves share: treatment cuts local events with no survival effect — her high-grade, extensive disease argues for maximal local treatment, not for promising what radiation and tamoxifen cannot deliver.^[17]

(C) Surveillance fence and follow-up (3 marks)

• She fails every surveillance fence: COMET enrolled hormone-receptor-positive grade 1-2 disease, and her high-grade, 28 mm, palpable lesion is the opposite population — monitoring trials do not cover her.^[13]
• Add the two quantitative fences: LORIS-eligible women still had 6.0% 10-year invasive recurrence without radiation, and one in five core non-high-grade DCIS cases hides invasion at excision — her higher-risk profile starts from worse.^[16]
• Grade sets her clock: invasive recurrence arrives at 76 months from high-grade disease (against 131 for low grade), with recurrence at 180 months doubling that at 60 — so follow-up is annual mammography for a decade, not short reassurance.^[18]