Breast Surgery

Exclude an eccentric hard retroareolar mass or nipple retraction (perform mammography + ultrasound + core biopsy if male breast cancer is suspected), review medications (spironolactone, finasteride, antiandrogens, anabolic steroids, cannabis), and check testosterone, LH, estradiol, prolactin, hCG, LFTs, and renal function when indicated. For persistent fibrous Simon Grade II–III gynecomastia (>12 months), perform combined power-assisted liposuction and minimal-incision circumareolar pull-through subareolar adenectomy, preserving a 5–8 mm retroareolar button.

Before: Immediate surgical excision of pubertal or drug-induced gynecomastia of <12 months duration, or sharp disc excision alone leaving a tethered 'saucer' deformity.

Now: Exclude an eccentric hard retroareolar mass or nipple retraction (perform mammography + ultrasound + core biopsy if male breast cancer is suspected), review medications (spironolactone, finasteride, antiandrogens, anabolic steroids, cannabis), and check testosterone, LH, estradiol, prolactin, hCG, LFTs, and renal function when indicated. For persistent fibrous Simon Grade II–III gynecomastia (>12 months), perform combined power-assisted liposuction and minimal-incision circumareolar pull-through subareolar adenectomy, preserving a 5–8 mm retroareolar button.

Males with gynecomastia vs. pseudogynecomastia, and the exclusion of male breast carcinoma — with the surgical element applying to persistent fibrous Simon Grade II–III gynecomastia of >12 months, exactly as the addendum's summary row states them.

Up to 75–90% of physiological pubertal gynecomastia resolves spontaneously within 1–2 years — early excision operates on tissue that would have regressed. Combining liposuction contouring with pull-through adenectomy prevents contour step-off and nipple saucer tether; the 5–8 mm retroareolar button is part of the printed technique.

• European Academy of Andrology (EAA) Gynecomastia Guidelines — as cited in the addendum summary table (no PMID printed)
• Plastic/Breast Surgical Consensus — as cited in the addendum summary table (no PMID printed)

Physiological bilateral multi-duct discharge: reassure, stop nipple stimulation, and check prolactin, TSH and medications. Pathologic discharge (spontaneous, unilateral, single-duct, bloody or clear serous): diagnostic mammography + retroareolar ultrasound (± breast MRI if negative), followed by wire/ductogram-localized single-duct microdochectomy (or central duct excision in postmenopausal women). Recurrent periductal mastitis / Zuska's fistula: mandatory smoking cessation + complete excision of the diseased lactiferous duct and fistula tract through the nipple core.

Before: Blind major duct excision for bilateral milky/greenish multi-duct discharge, or simple incision and drainage alone for recurrent subareolar lactiferous duct fistula.

Now: Physiological bilateral multi-duct discharge: reassure, stop nipple stimulation, and check prolactin, TSH and medications. Pathologic discharge (spontaneous, unilateral, single-duct, bloody or clear serous): diagnostic mammography + retroareolar ultrasound (± breast MRI if negative), followed by wire/ductogram-localized single-duct microdochectomy (or central duct excision in postmenopausal women). Recurrent periductal mastitis / Zuska's fistula: mandatory smoking cessation + complete excision of the diseased lactiferous duct and fistula tract through the nipple core.

Patients with nipple discharge (physiological vs. pathologic) and patients with recurrent periductal mastitis / Zuska's disease, exactly as the addendum's summary row stratifies them.

Pathologic single-duct discharge harbors a solitary intraductal papilloma in ~70–80% and occult DCIS/invasive carcinoma in 5–15% — it is never managed as physiological. Smoking damages subareolar ducts, causing squamous metaplasia and Zuska's fistulas; drainage alone without duct excision and cessation is the recurrence pattern this change removes.

• ASBrS / NCCN Breast Evaluation Guidelines — as cited in the addendum summary table (no PMID printed)

Differentiate cellular fibroadenoma from phyllodes on core biopsy (leaf-like stromal fronds, stromal hypercellularity, mitoses). Benign phyllodes: complete surgical excision, without routine re-excision for close or focally positive margins. Borderline and malignant phyllodes: wide local excision achieving >=1.0 cm negative surgical margins (or mastectomy if the breast-to-tumor ratio precludes 1 cm margins), OMITTING routine axillary SLNB or ALND unless nodes are clinically or pathologically positive.

Before: Routine simple enucleation for borderline/malignant phyllodes, or routine axillary sentinel lymph node biopsy (SLNB) for phyllodes tumors.

Now: Differentiate cellular fibroadenoma from phyllodes on core biopsy (leaf-like stromal fronds, stromal hypercellularity, mitoses). Benign phyllodes: complete surgical excision, without routine re-excision for close or focally positive margins. Borderline and malignant phyllodes: wide local excision achieving >=1.0 cm negative surgical margins (or mastectomy if the breast-to-tumor ratio precludes 1 cm margins), OMITTING routine axillary SLNB or ALND unless nodes are clinically or pathologically positive.

Patients with benign, borderline, and malignant phyllodes tumors of the breast, exactly as the addendum's summary row stratifies them.

Malignant phyllodes metastasizes hematogenously (predominantly to lungs) in 15–20% of cases, with <1–2% axillary nodal involvement — routine axillary staging adds lymphedema risk without oncologic benefit. The benign-grade exception (no routine re-excision for close/focally positive margins) is part of the printed standard; do not generalise the >=1.0 cm margin rule to benign tumors.

• NCCN Breast Cancer Guidelines (Phyllodes Tumor Section) 2024/2025 — as cited in the addendum summary table (no PMID printed)

Guide diagnostic workup by clinical presentation, epidemiologic risk, imaging, and core needle biopsy histopathology — selecting Gram, Ziehl-Neelsen (AFB), and PAS/GMS stains, prolonged lipophilic culture (Corynebacterium kroppenstedtii), and Mycobacterium tuberculosis PCR/culture as clinically indicated. Drain fluctuant abscesses via ultrasound-guided aspiration or small incision, treat confirmed infectious mastitis (e.g., lipophilic doxycycline/clarithromycin for Corynebacterium or anti-tuberculous therapy for TB), and reserve specialist-led corticosteroids or steroid-sparing methotrexate for confirmed non-infectious idiopathic granulomatous mastitis (IGM).

Before: Starting empiric systemic corticosteroids or methotrexate before excluding infection, or performing repeated wide surgical excisions for non-infectious granulomatous mastitis.

Now: Guide diagnostic workup by clinical presentation, epidemiologic risk, imaging, and core needle biopsy histopathology — selecting Gram, Ziehl-Neelsen (AFB), and PAS/GMS stains, prolonged lipophilic culture (Corynebacterium kroppenstedtii), and Mycobacterium tuberculosis PCR/culture as clinically indicated. Drain fluctuant abscesses via ultrasound-guided aspiration or small incision, treat confirmed infectious mastitis (e.g., lipophilic doxycycline/clarithromycin for Corynebacterium or anti-tuberculous therapy for TB), and reserve specialist-led corticosteroids or steroid-sparing methotrexate for confirmed non-infectious idiopathic granulomatous mastitis (IGM).

Women presenting with subacute inflammatory breast mass, sinuses, or sterile/granulomatous abscesses. Outcomes rated in the matrix: accurate microbiological diagnosis and fistula-free resolution.

Administering systemic steroids or methotrexate to undiagnosed tuberculous, fungal, or Corynebacterium-associated cystic neutrophilic granulomatous mastitis (CNGM) risks severe infectious progression, while repeated wide surgical excisions of sterile IGM cause chronic mammary fistulas and deformity (§6.1 quantitative column). Never initiate systemic corticosteroids or methotrexate for presumed idiopathic granulomatous mastitis before appropriate clinical, histopathological, and microbiological exclusion of infection — including Corynebacterium kroppenstedtii (cystic neutrophilic granulomatous mastitis), Mycobacterium tuberculosis, and fungal mastitis — and perform targeted needle aspiration/drainage or antimicrobial therapy when clinically indicated (§6.0 Guardrail 3).

Saudi/GCC provenance (§6.0/§6.2 frame): the infection-exclusion pathway carries explicit regional weight — the author-proposed Saudi adaptation requires that tuberculous mastitis and Corynebacterium infection are excluded on biopsy before prescribing systemic steroids for granulomatous mastitis, and the November 2025 Saudi Oncology Consensus (Alaklabi et al., PMID 41261349) is the chapter's labeled regional source for this pathway.

• Multidisciplinary IGM Consensus Statements (2021–2024) — as cited in Table 6.1
• 2025 Saudi Oncologists Consensus Statement — Alaklabi et al., Oncol Ther Nov 2025 (PMID 41261349)

In BCS with whole-breast irradiation, negative margins are 'no ink on tumor' for invasive carcinoma and >=2 mm for pure DCIS (SSO/ASTRO/ASCO consensus). Separate from invasive disease, active mammographic monitoring (every 6 mo +/- endocrine therapy) is an emerging shared-decision option only for strictly selected women >=40 y with low-risk Grade 1–2 HR+ DCIS without mass or comedo necrosis (COMET 2025), with surgery triggered by any new mass, microcalcification progression, or upgrade on biopsy.

Before: Conflating 2-year low-risk DCIS monitoring data with invasive breast cancer or standard care for all DCIS, or performing routine re-excision for clear margins >2 mm in DCIS or any negative margin in invasive cancer.

Now: In BCS with whole-breast irradiation, negative margins are 'no ink on tumor' for invasive carcinoma and >=2 mm for pure DCIS (SSO/ASTRO/ASCO consensus). Separate from invasive disease, active mammographic monitoring (every 6 mo +/- endocrine therapy) is an emerging shared-decision option only for strictly selected women >=40 y with low-risk Grade 1–2 HR+ DCIS without mass or comedo necrosis (COMET 2025), with surgery triggered by any new mass, microcalcification progression, or upgrade on biopsy.

Women aged >=40 y with screen-detected low-risk Grade 1–2 HR+ DCIS (COMET 2-y ipsilateral invasive cancer endpoint) vs. patients undergoing BCS + whole-breast radiation (local recurrence endpoint).

In COMET (n = 995 randomized; 957 analyzed), the 2-year cumulative rate of ipsilateral invasive breast cancer was 4.2% in the active-monitoring arm vs. 5.9% in the guideline-concordant surgery arm (difference −1.7%, upper 95% CI 0.9%, meeting the 5.0% non-inferiority margin). However, 2-year follow-up is short for hormone receptor-positive DCIS, ~71% took endocrine therapy, and 44% of the surgery arm declined operation — so active monitoring must be presented as an emerging option requiring long-term validation. Do not extrapolate the COMET findings to Grade 3 DCIS, DCIS with a palpable/sonographic mass, HR-negative DCIS, or invasive breast cancer; 5-to-10-year durability data are still pending (§6.0 Guardrail 2). COMET's monitoring protocol (§6.2): bilateral diagnostic mammography every 6 months, with core biopsy and surgical excision triggered by any new mass, increase in microcalcifications (>=5 mm), or upgrade to invasive carcinoma or Grade 3 DCIS.

• COMET RCT — Hwang et al., JAMA 2025;333:972–980 (PMID 39665585)
• SSO/ASTRO/ASCO Margin Consensus Guidelines — as cited in Table 6.1

Refer Stage II–III (cT2+ or cN+) TNBC (KEYNOTE-522 neoadjuvant pembrolizumab + chemotherapy → surgery → adjuvant pembrolizumab) and Stage II–III HER2+ breast cancer for neoadjuvant systemic therapy after placing tumor-bed and positive-node marker clips. Pathologists should report exact HER2 IHC scores (0, 0+/ultralow, 1+, 2+/ISH-, 2+/ISH+, 3+); HER2-low (IHC 1+ or 2+/ISH-) is a predictive biomarker for trastuzumab deruxtecan in advanced/metastatic disease after prior chemotherapy (DESTINY-Breast04), not a conventional HER2-positive early-stage indication.

Before: Upfront surgery before neoadjuvant therapy in Stage II–III TNBC/HER2+ disease, or reporting HER2 status simply as binary 'positive vs. negative' without IHC score (or treating HER2-low as eligible for trastuzumab in early breast cancer).

Now: Refer Stage II–III (cT2+ or cN+) TNBC (KEYNOTE-522 neoadjuvant pembrolizumab + chemotherapy → surgery → adjuvant pembrolizumab) and Stage II–III HER2+ breast cancer for neoadjuvant systemic therapy after placing tumor-bed and positive-node marker clips. Pathologists should report exact HER2 IHC scores (0, 0+/ultralow, 1+, 2+/ISH-, 2+/ISH+, 3+); HER2-low (IHC 1+ or 2+/ISH-) is a predictive biomarker for trastuzumab deruxtecan in advanced/metastatic disease after prior chemotherapy (DESTINY-Breast04), not a conventional HER2-positive early-stage indication.

Adults with Stage II–III TNBC (KEYNOTE-522: pCR, 5-y EFS, 5-y OS) and previously treated HER2-low (IHC 1+ or 2+/ISH-) metastatic breast cancer (DESTINY-Breast04: PFS and OS).

In KEYNOTE-522 (n = 1,174; median follow-up 75.1 mo), perioperative pembrolizumab + chemotherapy improved pCR (64.8% vs. 51.2%), 5-year EFS (81.2% vs. 72.2%; HR 0.65, 95% CI 0.51–0.83), and 5-year OS (86.6% vs. 81.7%; HR 0.66, 95% CI 0.50–0.87; p = 0.0015). In DESTINY-Breast04 (n = 557 HER2-low metastatic breast cancer after 1–2 lines of chemotherapy), T-DXd improved median PFS (9.9 vs. 5.1 mo; HR 0.50, p < 0.001) and median OS (23.4 vs. 16.8 mo; HR 0.64, p = 0.001). HER2-low is not a distinct biological subtype and is not equivalent to conventional HER2-positive disease: early-stage HER2-low breast cancers do NOT benefit from conventional adjuvant trastuzumab (NSABP B-47, §6.2).

Jurisdiction-specific regulatory labeling (§6.0/§6.2): HER2-low approvals and reimbursement must be verified by jurisdiction and treatment line (U.S. FDA Aug 2022; European EMA Jan 2023; local Saudi SFDA registration, hospital formulary criteria, and line-of-therapy restrictions must be confirmed independently). The November 2025 Saudi Oncology Consensus (Alaklabi et al., PMID 41261349) establishes statements on post-KEYNOTE-522 residual triple-negative disease management and antibody-drug conjugate sequencing in HER2-low metastatic disease, subject to local SFDA/hospital formulary access.

• KEYNOTE-522 OS Update — Schmid et al., NEJM 2024;391:1981–1991 (PMID 39282906)
• DESTINY-Breast04 — Modi et al., NEJM 2022;387:9–20 (PMID 35665782)
• NCCN Breast Cancer Guidelines — as cited in Table 6.1
• 2025 Saudi Oncologists Consensus Statement — Alaklabi et al., Oncol Ther Nov 2025 (PMID 41261349)

Omission of SLNB may be considered via shared decision-making in strictly eligible postmenopausal patients (aged >=50 y) with unicentric cT1 (<=2.0 cm), Grade 1–2, HR+/HER2- breast cancer and negative preoperative axillary ultrasound undergoing BCS, whole-breast irradiation, and endocrine therapy when nodal status will not alter adjuvant systemic or radiation therapy. Retain SLNB for premenopausal/<50 y patients, cT2+ (>2 cm), Grade 3, HER2+/TNBC, diffuse lobular histology, mastectomy, or when nodal staging informs systemic/radiation decisions.

Before: Routine SLNB in every postmenopausal woman with small ultrasound-negative luminal A-like cT1N0 cancer, or conversely claiming SLNB can be omitted in all cN0 breast cancers regardless of age, size, grade, biology, or mastectomy.

Now: Omission of SLNB may be considered via shared decision-making in strictly eligible postmenopausal patients (aged >=50 y) with unicentric cT1 (<=2.0 cm), Grade 1–2, HR+/HER2- breast cancer and negative preoperative axillary ultrasound undergoing BCS, whole-breast irradiation, and endocrine therapy when nodal status will not alter adjuvant systemic or radiation therapy. Retain SLNB for premenopausal/<50 y patients, cT2+ (>2 cm), Grade 3, HER2+/TNBC, diffuse lobular histology, mastectomy, or when nodal staging informs systemic/radiation decisions.

Postmenopausal women (aged >=50 y) with unicentric cT1 (<=2.0 cm), Grade 1–2, HR+/HER2- invasive breast cancer and negative preoperative axillary ultrasound undergoing BCS + whole-breast radiation + endocrine therapy. Outcomes rated in the matrix: 5-y DDFS (SOUND), 5-y IDFS (INSEMA), and lymphedema.

Evaluated separately by endpoint and analysis population: in SOUND (ITT n = 1,405; median age 60 y; 87.8% ER+/HER2-; primary endpoint 5-year DDFS, non-inferiority margin 2.5%), 5-y DDFS was 98.0% (no SLNB) vs. 97.7% (SLNB; HR 0.84, 90% CI 0.45–1.56; non-inferiority p = 0.02; 5-y DFS 93.9% vs. 94.7%; 5-y OS 98.4% vs. 98.2%). In INSEMA (per-protocol n = 4,858 / ITT n = 5,154; 90% cT1, 95% HR+/HER2-, 96% Grade 1–2; primary endpoint 5-year IDFS, non-inferiority margin HR 1.271), 5-y IDFS was 91.9% (95% CI 89.9–93.5) without SLNB vs. 91.7% (95% CI 90.8–92.6) with SLNB (per-protocol HR 0.91, 95% CI 0.73–1.14; ITT HR 0.98, 95% CI 0.79–1.20), with lower lymphedema (1.8% vs. 5.7%). Nodal staging may still change treatment in other patients (§6.2): identifying pN1–N2 burden can establish eligibility for adjuvant CDK4/6 inhibition (abemaciclib in monarchE [>=4 positive nodes, or 1–3 positive nodes with tumor >=5 cm or Grade 3]; ribociclib in NATALEE) or inform chemotherapy decisions in premenopausal women (RxPONDER). Full exclusion list per §6.0 Guardrail 1: premenopausal women, age <50 years, tumors >2.0 cm (cT2+), Grade 3 histology, HER2+ or triple-negative biology, multifocal/multicentric tumors, invasive lobular carcinoma with uncertain sizing, mastectomy, pre-neoadjuvant therapy, or cases where nodal staging would alter radiotherapy fields or systemic therapy.

Author-proposed regional adaptation (§6.2 Saudi & Gulf frame): because a high proportion of Saudi breast cancer patients are premenopausal (<50 years), surgeons should be especially vigilant not to extrapolate postmenopausal SLNB omission criteria (SOUND, INSEMA, and the 2025 ASCO Update, which require postmenopausal status and age >=50 years) to premenopausal women.

• 2025 ASCO Sentinel Lymph Node Biopsy Guideline Update — Park KU et al., J Clin Oncol 2025 (PMID 40209128)
• SOUND RCT — Gentilini et al., JAMA Oncol 2023 (PMID 37733364)
• INSEMA RCT — Reimer et al., NEJM 2025 (PMID 39665649)
• monarchE — as cited in §6.2 (PMID 36493792)
• RxPONDER — as cited in §6.2 (PMID 34914339)

Targeted Axillary Dissection (TAD) — combining preoperative clip placement in the biopsied positive node, localized excision of the clipped node, and dual-tracer SLNB (retrieving >=2–3 sentinel nodes) — may be considered in cN1-to-ycN0 responders to spare ypN0 patients from routine ALND.

Before: Mandatory full Level I–II Axillary Lymph Node Dissection (ALND) in all cN1 patients regardless of complete nodal response, or single-tracer SLNB without localizing the biopsy-clipped node.

Now: Targeted Axillary Dissection (TAD) — combining preoperative clip placement in the biopsied positive node, localized excision of the clipped node, and dual-tracer SLNB (retrieving >=2–3 sentinel nodes) — may be considered in cN1-to-ycN0 responders to spare ypN0 patients from routine ALND.

Adults with biopsy-proven cN1 (1–3 positive nodes) breast cancer converting clinically and sonographically to ycN0 after neoadjuvant systemic therapy (NST). Outcomes rated in the matrix: staging false-negative rate and axillary recurrence.

Whereas sentinel node biopsy alone after NST in cN1 patients had false-negative rates (FNR) of 12.6%–14.2% in Z1071 and SENTINA, dual-tracer mapping with >=3 nodes lowered FNR to <10%, and localizing/excising the clipped node plus SLNB (TAD; Caudle et al.) lowered the FNR to ~2.0% (95% CI 0.2%–7.0%). The rating is conditional on the full TAD technique — clip localization plus dual-tracer mapping plus adequate node retrieval; single-tracer SLNB without localizing the clipped node is the superseded routine, not an equivalent shortcut.

• NCCN Breast Cancer Guidelines 2024/2025 — as cited in Table 6.1
• Caudle et al., J Clin Oncol 2016 (TAD) — as cited in Table 6.1
• ACOSOG Z1071 / SENTINA / SN FNAC — as cited in Table 6.1