MBBS SAQ
Breast Cancer — SAQ
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A 52-year-old postmenopausal woman presents with a 3cm hard, irregular, painless lump in the upper outer quadrant of the left breast. There is a 1cm hard mobile lymph node in the left axilla. No skin changes or nipple discharge.
[1]Questions
[1]a) Describe the diagnostic approach (triple assessment) and what each component evaluates. (3 marks)
[1]Triple assessment (98% accurate when all three agree):
- Clinical examination: inspect (symmetry, skin, nipple) + palpate (all quadrants + axillary tail + axillary nodes)
- Imaging: mammography (looking for microcalcifications, spiculated mass, architectural distortion — BI-RADS classification) ± ultrasound (solid vs cystic, guide biopsy)
- Tissue sampling: core needle biopsy (gold standard — histology type, grade, ER/PR/HER2 receptor status)
b) The core biopsy shows invasive ductal carcinoma, grade 2, ER+/PR+, HER2-. What adjuvant systemic therapy is indicated? (2 marks)
[1]This is a Luminal subtype (ER+/PR+, HER2-). Adjuvant systemic therapy:
- Endocrine therapy: Since she is POSTMENOPAUSAL, an aromatase inhibitor (anastrozole or letrozole) for 5-10 years (superior to tamoxifen in postmenopausal women — ATAC trial).
- Chemotherapy may be added depending on tumour size, nodal status, grade, and genomic profiling (Oncotype DX).
c) What is the role of sentinel lymph node biopsy, and how is it performed? (3 marks)
[1]Sentinel lymph node biopsy (SLNB) is the standard for axillary staging in clinically node-negative breast cancer:
- Technique: Blue dye (methylene blue/patent blue V) and/or radioisotope (technetium-99) injected at the tumour/areola. The first draining node(s) are identified intraoperatively and excised.
- If negative: No further axillary surgery (avoids morbidity of clearance — lymphoedema, nerve injury).
- If positive (1-2 nodes): Axillary radiotherapy or clearance (ACOSOG Z0011: no benefit of clearance for 1-2 positive nodes in selected patients with BCT).
- If positive (3+ nodes): Formal axillary node clearance (levels I-III).
d) Name two significant side effects of aromatase inhibitor therapy. (2 marks)
[1]- Osteoporosis (reduced bone mineral density — due to complete oestrogen deprivation. Monitor with DEXA, give bisphosphonates if needed.)
- Arthralgia (joint pain — common, affects adherence). Also: hot flushes, vaginal dryness, increased cholesterol.
References
- [1]Waks AG, Winer EP. Breast Cancer Treatment: A Review. JAMA, 2019.PMID 30667505
- [2]Early Breast Cancer Trialists' Collaborative Group (EBCTCG), Darby S, McGale P, et al. Effect of radiotherapy after breast-conserving surgery on 10-year recurrence and 15-year breast cancer death. Lancet, 2011.PMID 22019144
- [3]Robson M, Im SA, Senkus E, et al. Olaparib for Metastatic Breast Cancer in Patients with a Germline BRCA Mutation. New England Journal of Medicine, 2017.PMID 28578601