Breast

High-yield ABSITE review organized by disease process. Anatomy first, then benign disease, high-risk lesions, in-situ carcinoma, invasive breast cancer with staging and systemic therapy, axillary management with a dedicated localization methods and SLNB tracers section, and post-treatment surveillance including SOZO.

Anatomy

• Blood supply: internal thoracic (mammary) — dominant ~60%; lateral thoracic; thoracoacromial; posterior intercostals.
• Venous drainage: parallels arteries + Batson’s plexus — valveless venous system, hematogenous route direct to the vertebrae (spine metastases).
• Cooper’s ligaments: fibrous suspensory ligaments; tethering causes skin dimpling / retraction (cancer sign).
• Lymphatic drainage:
  • ~ 97% → axilla.
  • ~ 3% → internal mammary chain.
• Axillary levels:
  • I — lateral to pec minor.
  • II — posterior to pec minor.
  • III — medial to pec minor (breast ALND standard is I–II; melanoma is I–III).
• Rotter’s nodes — interpectoral, between pec major and pec minor.
• Nerves at risk in axillary surgery:
  • Long thoracic (Bell’s) — serratus anterior. Injury → winged scapula.
  • Thoracodorsal — latissimus dorsi. Injury → weakness in adduction / internal rotation (“can’t push up out of a chair”).
  • Medial pectoral — innervates pec major AND pec minor.
  • Lateral pectoral — pec major only.
  • Intercostobrachial (T2) — medial upper arm sensation. Often sacrificed; expected.

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Benign Breast Disease

Breast pain (mastalgia)

• Common, self-limited. Worse in the late luteal phase.
• Reassurance is first-line; for severe pain — trials of danazol, bromocriptine, tamoxifen, evening primrose oil, vitamin E (all mixed evidence).

Mondor’s disease

• Superficial thrombophlebitis of the lateral thoracic vein or a tributary.
• Presents as a tender, palpable subcutaneous cord, usually after recent surgery, trauma, or inflammation.
• Rarely associated with malignancy.
• Treatment: NSAIDs, warm compresses, reassurance.

Fibrocystic disease

• Most common in perimenopausal women — pain, nipple discharge, cyclic lumps.
• Simple cyst on ultrasound → observe.
• Symptomatic → aspirate.
• Bloody aspirate or recurrent after aspiration → cytology and surgical excision.
• ADH / ALH on cytology → increased cancer risk (see high-risk lesions).

Fibroadenoma

• Dominant, mobile, well-circumscribed mass.
• Workup:
  • < 35 y — ultrasound (dense breasts).
  • ≥ 35 y — mammography.
  • Any uncertainty → core needle biopsy.
• Concordant benign fibroadenoma without risk factors → bi-annual ultrasound.
• Growing / uncertain → excisional biopsy.
• Variants:
  • Giant fibroadenoma > 6 cm — hard to distinguish from phyllodes.
  • Complex fibroadenoma — risk factor for carcinoma (contains cysts, sclerosing adenosis, papillary apocrine hyperplasia, or calcifications).
  • Tubular adenoma — benign.

Phyllodes tumor

• Sub-classifications: benign, borderline, malignant.
• ~ 10% malignant potential (higher if > 5 mitoses / HPF).
• Rare hematogenous metastasis; does NOT go to nodes → no SLNB or ALND.
• Treatment: wide local excision with 1 cm margins.

Nipple discharge

• Bloody nipple discharge — most common cause = intraductal papilloma (not premalignant).
• Concerning features: bloody, spontaneous, persistent, unilateral.
  • < 40 y — ~ 3% cancer risk.

  • 60 y — ~ 32% cancer risk.

• Best diagnostic test = duct excision.
• Treatment = subareolar resection of involved duct + papilloma.

Duct ectasia

• Dilation of subareolar duct in peri-/postmenopausal women.
• Cheesy, viscous nipple discharge.
• Asymptomatic → observe. Symptomatic → duct excision.

Breast infections

• Most common organism: Staphylococcus aureus.
• Lactational — blocked lactiferous ducts.
  • No abscess → antibiotics, continue breastfeeding.
  • Abscess → aspirate + antibiotics, continue breastfeeding. I&D if no resolution.
  • Complication: milk fistula.
• Non-lactational — periductal, associated with smoking + duct ectasia.
  • Antibiotics; I&D if abscess.
• Recurrent, non-resolving mastitis → skin biopsy to rule out inflammatory breast cancer.

Sclerosing adenosis

• Presents as microcalcifications; diagnose by CNB.
• Not premalignant. No atypia + concordant imaging → observe.

Radial scar

• Also called sclerosing papillary proliferations or benign sclerosing ductal proliferation.
• Mammographically looks like a small invasive cancer.
• Treatment: excisional biopsy — CNB alone insufficient; associated with small increased cancer risk.

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High-Risk Lesions

Atypical lobular hyperplasia (ALH)

• Marker of increased risk (~ 8–12-fold lifetime, ~ 1% per year).
• Not premalignant, but often incidental to the mammographic finding → excisional biopsy for discordance.

Atypical ductal hyperplasia (ADH)

• 4–5-fold increased invasive-cancer risk.
• CNB → excisional biopsy because of 9–30% upstaging to DCIS and ~ 3% to invasive cancer on excision.

Lobular carcinoma in situ (LCIS)

• Multifocal and bilateral; genetic predisposition. 90% ER/PR+, HER2-.
• Marker for ~ 40% lifetime cancer risk in EITHER breast — cancer that develops is usually ductal, not lobular.
• Treatment: wire (or wire-free) localized excision.
• Positive margin? No re-excision needed — adjuvant hormonal therapy instead.
• Pleomorphic LCIS variant → treated like DCIS.

Ductal carcinoma in situ (DCIS)

• Malignant ductal epithelial cells without invasion — premalignant.
• Risk: ~ 50% ipsilateral invasive cancer, ~ 5% contralateral.
• Presentation: mostly non-palpable microcalcifications on mammogram.
• DCIS margin = 2 mm.
• Treatment:
  • BCT (lumpectomy + whole-breast RT) — most common. RT reduces local recurrence ~ 50% but no OS benefit.
  • Large, multi-quadrant, or BCT contraindication → simple mastectomy + SLNB. SLN sampling needed because up to 25% show invasive component on final path.
  • Skin-sparing / nipple-sparing mastectomy with immediate reconstruction is an option.
• Adjuvant hormonal therapy:
  • Premenopausal → tamoxifen.
  • Postmenopausal → aromatase inhibitor.
• Most aggressive DCIS subtype: comedo — characterized by necrosis. Simple mastectomy + adjuvant hormonal therapy.

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Screening

• Low risk: age 40, every 2–3 years → annually after 50.
• High risk: start 10 years before youngest first-degree diagnosis.
• Hereditary syndromes with increased risk: BRCA1/2, Li-Fraumeni (p53), Cowden (PTEN), Peutz-Jeghers (STK11), CDH1.
• BRCA1/2 — 10–20-fold risk → 30–60% by age 60. Screening age 25 with annual mammogram + MRI, pelvic exam, CA-125.
• BRCA cumulative risk:
  • BRCA1 — 65% breast, 40% ovary.
  • BRCA2 — 45% breast, 10% ovary.
• Mammographic malignancy signs: irregular / spiculated borders, distortion, small linear branching calcifications.
• BIRADS:
  • 0 — incomplete, need further imaging.
  • 1 — negative, routine.
  • 2 — benign, routine.
  • 3 — probably benign, 6-mo follow-up.
  • 4 — suspicious, biopsy.
  • 5 — highly suggestive, biopsy.
  • 6 — biopsy-proven, excision.

Gail model

• Predicts 5-year and lifetime breast cancer risk.
• Variables: age, age at menarche, age at first birth (or nulliparous), family history in first-degree relatives, prior breast biopsies, atypical hyperplasia count, race/ethnicity.
• Underestimates in patients with strong family history, prior DCIS/LCIS/IDC.

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Invasive Breast Cancer

Categories

• Ductal carcinoma — most common (~ 75%).
• Lobular carcinoma — less common; does not typically calcify; multifocal / bilateral tendencies.
• Signet-ring cell — worst prognosis.

Inflammatory breast cancer

• Angry, erythematous, warm, rapidly diffuse involvement with peau d’orange.
• Hallmark biopsy: dermal lymphatic invasion.
• Staging: T4d by definition = at least Stage IIIB.
• Treatment: neoadjuvant chemo → MRM → adjuvant chemoRT. No BCT.

Paget’s disease

• Eczematous scaling / ulceration of the nipple-areolar complex.
• Cells with clear cytoplasm and enlarged nucleoli.
• Marker of underlying DCIS or IDC (generally ER-/PR- and HER2+).
• Treatment: mastectomy including NAC + SLNB.

Male breast cancer

• < 1% of breast cancers, usually ductal.
• Risk factors: family history, Klinefelter’s, BRCA2 (accounts for ~ 15% of male breast cancer).
• Treatment: MRM. Similar stage-for-stage prognosis to women; usually presents later.

Breast cancer in pregnancy

• 1st trimester → MRM (radiation deferred).
• Late 2nd / 3rd trimester → BCT an option; SLN with modified isotope dose; adjuvant chemo post-op; radiation postpartum.

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Staging (AJCC/NCCN)

• T stage:
  • T1 0–2 cm.
  • T2 2–5 cm.
  • T3 > 5 cm.
  • T4 chest wall / skin (T4a chest wall, T4b skin, T4c both, T4d inflammatory).
• N stage:
  • N1 1–3 nodes.
  • N2 4–9 nodes.
  • N3 ≥ 10 nodes OR supra- / infraclavicular.
• M — distant metastasis. Isolated tumor cells < 0.2 mm do NOT constitute mets (pN0(i+)).
• Stage snapshot:
  • I — small tumor, no nodes (T1N0M0) → surgery + adjuvant as indicated.
  • II — larger tumor or minor nodal (T3N0 or T2N1) → surgery + adjuvant.
  • IIIA/B — locally advanced (T4N0, T3N2) → surgery first vs neoadjuvant.
  • IIIC — clavicular nodes (any T, N3, M0) → neoadjuvant + surgery if responsive.
  • IV — distant mets → definitive systemic therapy.

Prognostic factor hierarchy

• Nodal status is the single most prognostic factor.
  • 0 nodes → ~ 75% 5-yr survival.
  • 4–10 nodes → ~ 40% 5-yr survival.

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Systemic Therapy

Chemotherapy

• Indications (ABSITE):
  • Tumors > 1 cm.
  • Exception: hormone-receptor-positive, node-negative tumors with favorable Oncotype may skip chemo → hormonal therapy alone.
  • Positive nodes.
  • Triple-negative tumors.
• Regimen: TAC
  • Taxane (docetaxel) — peripheral neuropathy.
  • Adriamycin (doxorubicin) — cardiomyopathy.
  • Cyclophosphamide — hemorrhagic cystitis (mesna prevents).
• Neoadjuvant chemotherapy indications: locally advanced / inoperable (inflammatory, N2/N3, T4); large tumor-to-breast ratio in a patient wanting BCT.

Radiation

• Whole-breast RT after lumpectomy decreases local recurrence and improves survival. Boost to the tumor bed.
• Post-mastectomy radiation (PMRT): ≥ 4 positive nodes, fixed nodes, internal mammary nodes, skin/chest wall involvement, positive margins, T3/T4.
• Regional nodal RT: > 4 positive LN → supraclavicular, infraclavicular, axillary. Central/inner tumor → internal mammary nodes. 1–3 positive nodes = grey zone.
• RT after chemo, not before.
• NCCN — omit RT in women > 70 y with clinically N0, ER+, T1 tumor treated with lumpectomy + negative margins + hormonal therapy.

Endocrine therapy

• ER+ / PR+ prognosis > ER-/PR-.
• PR+ > ER+. Both = best.
• Premenopausal → tamoxifen × 5 years.
• Postmenopausal → aromatase inhibitor × 5 years.
• Tamoxifen AEs: thromboembolism, endometrial cancer.

HER2 targeted therapy

• HER2/neu positive = worse prognosis without therapy.
• Trastuzumab (Herceptin) × 1 year.

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Axillary Staging

SLNB

• Indicated for all invasive tumors (with cN0 axilla).
• Detection ~ 95% single-agent; ~ 99% dual tracer.
• False-negative rate ~ 5–10%.

ACOSOG Z0011 (2011 landmark trial)

• Population: T1–T2, cN0, planned BCT + whole-breast RT, ≤ 2 positive SLNs.
• Result: no benefit to completion ALND — equal locoregional recurrence, DFS, OS.
• Applies specifically to that population — does not apply to mastectomy, > 2 positive SLNs, no XRT, T3+.

AMAROS (2014)

• cN0 with positive SLN: axillary radiation vs ALND — equivalent recurrence and DFS, less lymphedema with radiation.
• Extends the “less axillary surgery” logic to mastectomy patients.

Axillary dissection — indications

• Clinically positive nodes confirmed by FNA / CNB.
• Sentinel nodes not identified.
• > 2 positive SLNs in non-Z0011 setting.
• Inflammatory cancer (mandatory).
• Neoadjuvant with residual disease.
• Take level I and II for standard breast. Levels I–III for melanoma.

Targeted axillary dissection (TAD)

• For neoadjuvant chemotherapy patients with initially biopsy-proven positive node.
• Clip the positive node before neoadjuvant → after neoadjuvant, SLNB + removal of the clipped node with wire, seed, or radar reflector.
• Improves accuracy — reduces false-negative rate to acceptable range.

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Localization Methods and SLNB Tracers

Detailed workflow lives on the lumpectomy + SLNB case prep. Board-relevant summary:

Lesion localization systems

• Wire — day of surgery only, requires same-day radiology.
• Radioactive seed (I-125, RSL) — 1–5 days pre-op, gamma probe.
• Savi Scout (radar/infrared) — up to 30+ days pre-op. No radiation, no magnet. MRI-safe. Baylor Dallas + JPS.
• LOCalizer (RFID) — days-to-weeks pre-op. Unique tag ID enables multiple lesion identification. MRI-friendly. Baylor Waxahachie.
• Magseed (magnetic) — years pre-op. Sentimag probe. Ferromagnetic instrument interference → non-magnetic (titanium/plastic) retractors during localization step.
• Molli / Sirius Pintuition — other magnetic marker systems, same instrument caveat.

SLNB tracers

• Tc-99m sulfur colloid — radiotracer, gamma probe. Standard of care.
• Isosulfan blue — dye, ~ 1% anaphylaxis risk; avoid in pregnancy.
• Methylene blue — cheaper alternative. Do not inject dermally (skin necrosis). Caution G6PD deficiency and pregnancy.
• ICG (indocyanine green) — NIR fluorescence. No radiation, no dye reaction.
• Magtrace (SPIO / Sienna+) — magnetic-based tracer with Sentimag probe. The “plastic instruments” tracer — ferromagnetic instruments interfere.

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Lymphedema and SOZO Surveillance

• Lymphedema rates: SLNB alone ~ 5–7%; ALND 20–30% at 5 yr; higher with axillary radiation, obesity.
• SOZO (bioimpedance spectroscopy) — measures extracellular fluid via bioimpedance → L-Dex score.
  • PREVENT trial (Ridner 2019): early compression triggered by rising L-Dex reduced progression to chronic lymphedema from ~ 35% to ~ 7%.
  • Standard protocol: baseline preop, then every 3–6 months for 3 years, then annually.
  • Community standard at Baylor and increasingly nationwide.
• Patient education routine: no IV lines / blood draws / BP cuffs on the affected arm; compression sleeve for air travel and heavy activity.
• Stewart–Treves syndrome — lymphangiosarcoma in chronic lymphedema. Extremely rare, decades out. Dark purple upper-arm nodule → biopsy urgently.

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Rapid-Fire Questions

• Q: Most prognostic staging factor in breast cancer? A: Nodal status.

• Q: SLNB detection rates with tracers? A: Single-agent ~ 95%. Dual (Tc-99m + blue) ~ 99%.

• Q: ACOSOG Z0011 population and threshold? A: T1–T2, cN0, BCT + whole-breast RT, ≤ 2 positive SLNs → no benefit to ALND.

• Q: AMAROS take-home? A: For SLN-positive cN0, axillary radiation is equivalent to ALND with less lymphedema.

• Q: DCIS margin? A: 2 mm. Invasive: no ink on tumor.

• Q: BCT absolute contraindications? A: Pregnancy requiring RT during pregnancy, prior radiation, multicentric disease, persistent positive margins, inflammatory cancer.

• Q: Inflammatory breast cancer treatment? A: Neoadjuvant chemo → MRM → adjuvant chemoRT. No BCT.

• Q: Male breast cancer operation? A: MRM.

• Q: Which tracer requires plastic / non-ferromagnetic instruments? A: Magtrace (SPIO) for SLNB — Sentimag probe is degraded by ferromagnetic instruments. Same principle for Magseed lesion localization.

• Q: Localization system at Baylor Dallas + JPS? A: Savi Scout (radar).

• Q: Localization system at Baylor Waxahachie? A: LOCalizer (RFID).

• Q: Bloody nipple discharge — most common cause? A: Intraductal papilloma. Duct excision.

• Q: Recurrent non-resolving mastitis — next step? A: Skin biopsy to rule out inflammatory breast cancer.

• Q: Prophylactic mastectomy indication — top of the list? A: BRCA1/2.

• Q: Tamoxifen side effects? A: Thromboembolism, endometrial cancer.

• Q: Levels of ALND? A: I (lateral to pec minor), II (posterior), III (medial). Breast → I–II; melanoma → I–III.

• Q: Winged scapula after axillary dissection? A: Long thoracic nerve injury.

• Q: Weakness in adduction after axillary dissection? A: Thoracodorsal injury.

• Q: Rotter’s nodes? A: Interpectoral nodes, between pec major and pec minor.

• Q: Poland’s syndrome? A: Hypoplasia of the chest wall, amastia, hypoplastic shoulder, absent pectoralis muscle.

• Q: Batson’s plexus? A: Valveless venous plexus responsible for direct hematogenous spread to the spine.

• Q: Chronic lymphedema × 10 yr + dark purple upper-arm lesion? A: Stewart–Treves syndrome (lymphangiosarcoma).

• Q: SOZO — what does it measure, when do you do it, why do we care? A: Bioimpedance spectroscopy for extracellular fluid → L-Dex score. Baseline preop + every 3–6 mo × 3 yr. Rising L-Dex → early compression, prevents chronic lymphedema (PREVENT ~ 35% → ~ 7%).

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Quick Reference Table — Localization Systems

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Quick-Reference Cards

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Related Case Preps

• Lumpectomy + SLNB — technique, localization deep dive.
• Total Mastectomy ± SLNB — mastectomy with SLNB.
• Axillary Lymph Node Dissection — ALND stand-alone or as MRM component.
• Modified Radical Mastectomy — total mastectomy + level I–II ALND en bloc.

Related Landmark Papers

• ACOSOG Z0011 (Giuliano 2011 / 2017) — no benefit to completion ALND for ≤ 2 positive SLNs in BCT patients.

Figures