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• What to do right now?
  • Stop cisplatin permanently:
    • Grade-3 renal toxicity signals significant tubular injury with risk of incomplete recovery:
      • Continuing platinum can cause irreversible damage
    • FDA labeling flags severe, cumulative nephrotoxicity and advises dose reduction or alternatives in renal impairment Cancer Treatment and Diagnosis+1
  • Continue radiation on schedule and switch the systemic partner only if the patient can tolerate it:
    • Preferred: 
      • RT + cetuximab (loading 400 mg / m² → 250 mg / m² weekly):
        • If infusion tolerance and skin toxicity risk acceptable
          • Evidence for postoperative use is not as mature as for cisplatin:
            • But RTOG 0234 showed feasibility and favorable signals with cetuximab-based regimens
          • Several groups (and guidelines) allow cetuximab when cisplatin is contraindicated
      • If not feasible, RT alone is acceptable PMC
• Supportive care (same day):
  • Nephrology consult:
    • Classify per CTCAE v5.0 and KDIGO:
      • Check urine studies,:
        • Mg / K / Ca / PO₄ ctep.cancer.gov+1
  • Aggressive IV hydration with isotonic saline and magnesium supplementation:
    • Hold other nephrotoxins:
      • NSAIDs, IV contrast, aminoglycosides
  • Routine mannitol isn’t required:
    • May be considered selectively at very high cisplatin doses:
      • Not applicable here since cisplatin is being stopped eviq.org.au
  • Frequent labs (serum Cr / eGFR, electrolytes) until recovery:
    • Document nadir eGFR for the chart
• What NOT to do?
  • Do not re-challenge with cisplatin after a grade-3 AKI in the adjuvant setting:
    • Renal injury may recover incompletely and worsen with further exposure eviq.org.au+1
  • Avoid reflex “swap to carboplatin” in the adjuvant post-op setting after severe AKI:
    • Carboplatin is renally cleared and, while less nephrotoxic, lacks adjuvant level-I evidence with RT for head and neck
    • Prior cisplatin exposure can also predispose to carboplatin – AKI
    • If considered at all:
      • Do so only with nephrology input and careful pharmacokinetics Frontiers
• Finishing the course (practical scenarios):
  • If some cisplatin already given but < 200 mg /m²: 
    • Aim to complete RT with cetuximab if the patient can tolerate it:
      • Otherwise proceed with RT alone
  • ≥ 200 mg / m² is the commonly cited efficacy threshold in CRT literature:
    • If already achieved, simply finish RT BC Cancer
  • If weekly cisplatin was planned (JCOG1008 context): 
    • That RCT supports weekly as a valid starting schedule post-op:
      • But once grade-3 AKI occurs:
        • The same rules appl:
          • Stop cisplatin and transition as above PubMed
• One-page order set:
  • Hold cisplatin permanently.
  • RT: 
    • Continue per plan
    • Coordinate new concurrent agent start within 0 to 3 days
  • Cetuximab (if chosen):
    • 400 mg / m² load → 250 mg / m² weekly through RT
      • Premedicate; dermatitis prophylaxis PMC
  • Renal bundle: 
    • NS 1 to 2 L / day IV while inpatient or symptomatic
    • MgSO₄ per lab
    • Stop ACEi/ARBs/NSAIDs/IV contrast if possible
    • Daily weights
    • I/Os eviq.org.au
  • Monitoring: 
    • BMP / Mg daily until stable:
      • Then every 48 to 72 hours
    • Re-stage eGFR at 2 to 4 weeks
    • KDIGO-based follow-up for AKI recovery KDIGO
• Bottom line: 
  • After grade-3 AKI, do not give more cisplatin
  • Finish radiation and, if feasible, add cetuximab (or proceed with RT alone) while executing a tight renal-recovery plan (hydration, magnesium, nephrotoxin avoidance, close labs)
  • This balances cure intent with kidney safety, in line with contemporary supportive-care guidance

• What was the primary objective of the SOUND trial?
  • Answer:
    • To determine whether sentinel lymph node biopsy (SLNB) can be safely omitted in women with early-stage, clinically node-negative breast cancer with negative axillary ultrasound:
      • Without compromising distant disease-free survival
• What does “SOUND” stand for in this trial?
  • Answer:
    • SOUND stands for:
      • Sentinel node vs Observation after axillary UltraSouND
• What were the eligibility criteria for patients
  • Answer:
    • Women with unifocal invasive breast cancer ≤ 2.0 cm
    • Clinically node-negative
    • Negative axillary ultrasound (AUS)
    • Undergoing breast-conserving surgery
    • No prior neoadjuvant therapy
• Describe the study design of the SOUND trial:
  • Answer:
    • Phase 3, multicenter, randomized non-inferiority trial
      • Two arms:
        • SLNB group vs. observation (no axillary surgery)
    • Primary endpoint:
      • 5-year distant disease-free survival (DDFS)
• What was the primary endpoint, and how was non-inferiority defined?
  • Answer:
    • Primary endpoint:
      • 5-year distant disease-free survival (DDFS)
    • Non-inferiority margin:
      • Upper bound of 95% CI for the hazard ratio had to be ≤ 1.50
• What were the key results of the SOUND trial
  • Answer:
    • 5-year DDFS:
      • 95.5% (observation) vs. 96.2% (SLNB)
    • Non-inferiority was demonstrated
    • No significant difference in axillary recurrence or overall survival
• What does this trial suggest about the role of SLNB in modern breast cancer management?
  • Answer:
    • SLNB may be safely omitted in carefully selected patients with low-risk, early-stage breast cancer and negative AUS:
      • Reinforcing a less invasive, de-escalated approach
• What were the secondary outcomes, and how did they compare?
  • Answer:
    • Overall survival:
      • No difference:
        • OS at 5 yr: 
          • 98.4% vs 98.2%
    • Axillary recurrence:
      • < 1.5% in both arms
    • Quality-of-life data (previous reports) favored the observation group
• What is the clinical significance of using axillary ultrasound as a triage tool?
  • Answer:
    • Axillary ultrasound helps identify patients who do not need SLNB, reducing unnecessary surgery in node-negative disease with high diagnostic accuracy
• How does the SOUND trial compare to ACOSOG Z0011 and INSEMA?
  • Answer:
    • ACOSOG Z0011:
      • Tested omission of ALND after positive SLNB
    • INSEMA:
      • Tested omission of SLNB in cN0 patients undergoing BCS + radiation
    • SOUND:
      • Focused on completely omitting axillary surgery in AUS-negative patients
• What were some exclusion criteria in the trial
  • Answer:
    • Multifocal or multicentric disease
    • Tumors > 2.0 cm
    • Mastectomy patients
    • Neoadjuvant therapy
    • Prior axillary surgery
• What were some limitations of the SOUND trial
  • Answer:
    • Limited to low-risk patients
    • Mostly postmenopausal, HR-positive / HER2-negative tumors
    • Not generalizable to mastectomy, young, or high-risk patients
• How might omission of SLNB affect decisions about adjuvant systemic therapy?
  • Answer:
    • Without nodal staging, oncologists may rely more on tumor biology, imaging, and genomic testing to guide chemotherapy decisions
• What were the main benefits of omitting SLNB noted in the trial?
  • Answer:
    • Reduced risk of lymphedema
    • Better arm mobility
    • Improved quality of life
    • Shorter operative times and fewer complications
• Based on SOUND, how would you counsel a 62-year-old woman with a 1.5 cm ER+ / HER2 negative tumor and negative axillary ultrasound?
  • Answer:
    • She is a candidate for SLNB omission:
      • I would explain that observation is safe, doesn’t affect survival, and lowers surgical risk, but the decision should involve the oncology team to ensure systemic therapy isn’t compromised

• High-risk triggers (guideline-concordant):
  • Positive margin (R+) or close margin (institutional cutoffs commonly < 1 to 5 mm)
  • Extranodal extension (ENE / ECS +) in any positive node
• Rationale:
  • These were the features driving benefit from adding concurrent cisplatin to postoperative RT in the pivotal randomized trials and follow-ups PMC+2PMC+2
• Pivotal trials:
  • EORTC 22931 (Bernier, NEJM 2004):
    • Design: 
      • Post-op RT alone (66 Gy) vs RT + cisplatin 100 mg / m² q3wk ×3
    • 5-yr outcomes (KM estimates): 
      • OS 53% vs 40%
      • PFS 47% vs 36%:
        • Both favoring CRT
      • Reported hazard ratios (RT + Cisplatin vs RT): 
        • OS HR ≈ 0.70–0.75
        • PFS HR 0.75:
          • Benefit across most high-risk features
    • Takeaway: 
      • Clear KM separation for DFS / OS with combined therapy New England Journal of Medicine+2PubMed+2
  • RTOG 9501 (Cooper, NEJM 2004; 10-yr update 2012):
    • Design: 
      • Post-op RT alone (60 Gy/6 wk) vs RT + cisplatin 100 mg / m² on days 1, 22, 43
    • Overall cohort (10-yr KM): 
      • LRF 28.8% vs 22.3% (p=0.10)
      • DFS 19.1% vs 20.1% (p=0.25)
      • OS 27.0% vs 29.1% (p=0.31)
        • No significant advantage in the unselected population
      • Key subset (pre-specified high-risk: R+ and / or ENE+):
        • LRF 33.1% (RT) vs 21.0% (CRT), p=0.02
        • DFS 12.3% vs 18.4%, p=0.05
        • OS 19.6% vs 27.1%, p=0.07 (trend)
        • KM curves:
          • Markedly diverge in this subgroup, establishing R+ / ENE+ as the clearest indication for cisplatin-RT PubMed+1
  • Cross-trial comparative / pooled insight:
    • Bernier et al., Head & Neck 2005 compared EORTC 22931 and RTOG 9501:
      • Concluded the greatest benefit from CRT accrues to patients with:
        • ENE+ and / or positive margins PubMed+1
    • Updated combined analysis (2025):
      • Again supports an OS benefit for CRT across the combined cohorts:
        • While noting competing non-cancer mortality:
          • Still, ENE and / or R+ remain the most reproducible risk features prompting CR PubMed+1
• How to apply at tumor board:
  • Offer adjuvant cisplatin-RT when any of the following are present::
    • Positive margin:
      • R1:
        • Re-resection preferred when feasible, otherwise CRT
    • Close margin:
      • Where institutional policy treats as high risk:
        • Commonly < 1 to 5 mm, site-dependent
    • ENE / ECS+ in a lymph node (any extent) PMC
    • Intermediate-risk (e.g., PNI, LVI, pT3, pN2 without ENE, multiple nodes but ENE-negative):
      • RT alone remains standard:
        • CRT generally not indicated absent R+ / ENE+ ACS Publications
  • Cisplatin fitness: 
    • If contraindicated (CrCl < 60 mL/min, grade ≥ 2 SNHL, neuropathy, poor PS):
      • Use RT alone or alternative systemic partner per site-specific guidance:
        • But the randomized survival gain post-op is with cisplatin ACS Publications
• Quick “exam-pearl” summaries:
  • EORTC 22931: 
    • KM curves separate for PFS / OS:
      • CRT beats RT in high-risk patients overall New England Journal of Medicine
  • RTOG 9501 (10-yr): 
    • Whole cohort:
      • No OS benefit
      • R+ / ENE+ subset: 
        • Better LRC and DFS, OS trend with CRT:
          • This is the clinical trigger PubMed
    • Define “close” carefully:
      • Many centers treat < 5 mm (some < 3 mm or < 1 mm by subsite) as high-risk when re-resection isn’t possible PMC+1
• Bottom line:
  • After resection of LA-HNSCC:
    • Adjuvant cisplatin-RT is indicated for ENE+ and positive (or institutionally “close”) margin:
      • The exact groups where the Kaplan–Meier curves in RTOG 9501 and EORTC 22931 show the clearest advantage for adding chemotherapy to RT

• Sentinel lymph node biopsy (SLNB):
  • Has replaced axillary lymph node dissection (ALND) as the primary method of axillary staging for patients with early stage breast cancer, based on data from:
  • NSABP B-32 (Phase III RCT) — SLNB vs ALND in cN0 patients:
    • No differences in overall survival, disease-free survival, or regional control:
      • Markedly less morbidity with SLNB
    • Conclusion:
      • If the sentinel node is negative, SLNB alone is appropriate and safe
  • Milan / IEO Randomized Trial (Veronesi et al., NEJM 2003) — SLNB with ALND only if SLN positive vs routine ALND:
    • SLNB was safe and accurate, reducing need for complete dissection without compromising outcomes
  • ALMANAC RCT (UK) — SLNB vs standard axillary treatment:
    • Similar cancer control with significantly lower arm morbidity and better quality of life after SLNB:
      • Tecommended as treatment of choice for early cN0 disease
  • Foundational validation work that enabled the shift to SLNB:
    • Krag et al., NEJM 1998 (Multicenter validation):
      • Demonstrated reliable identification of the sentinel node and accuracy of the technique
    • Giuliano et al., Ann Surg 1994 (Feasibility / accuracy):
      • First clinical series showing lymphatic mapping and SLN biopsy accurately stage the axilla
• Changes in patient presentation and advancements in systemic therapy:
  • Have led clinicians to question the utility of ALND even in the presence of involved nodes
• The American College of Surgeons Oncology Group (ACOSOG) Z0011 trial:
  • Randomized women with cT1 / cT2 tumors undergoing breast conservation with one or two positive sentinel nodes:
    • To undergo ALND vs. no additional axillary surgery
  • Results showed no difference in local recurrence, disease-free survival (DFS), or overall survival (OS) between the groups
    • The authors concluded that ALND was not indicated in this setting
• One of the major advantages of SLNB compared to ALND:
  • Is the ability to stage the axilla with reduced rates of lymphedema
• A meta-analysis of five randomized controlled trials (including the Z0011 trial):
  • Reported a 70% reduction in risk of lymphedema with SLNB compared to ALND
• Multi-gene assays:
  • Such as the 21-gene recurrence score (RS):
    • Have provided prognostic information regarding risk of distant recurrence for patients with:
      • Node-negative, ER+ breast cancers
    • Although evidence suggests that adding chemotherapy to endocrine therapy does result in improved DFS and OS for node-positive patients:
      • Exploratory data suggest that this may not be true for all patients:
        • A retrospective analysis of the RS performed on 367 specimens from the SWOG 8814 trial:
          • Showed that RS was prognostic for DFS and OS in node-positive patients
      • The National Comprehensive Cancer Network allows patients with 1 to 3 positive nodes to consider the 21-gene recurrence score to determine benefit from chemotherapy
• References
  • Giuliano AE, Ballman K, McCall L, et al. Locoregional recurrence after sentinel lymph node dissection with or without axillary dissection in patients with sentinel lymph node metastases: long-term follow-up from the American College of Surgeons Oncology Group (Alliance) ACOSOG Z0011 randomized trial. Ann Surg. 2016; 264(3):413-420.
  • Glechner A, Wockel A, Gartlehner G, et al. Sentinel lymph node dissection only versus complete axillary lymph node dissection in early invasive breast cancer: a systematic review and meta-analysis. Eur J Cancer. 2013;49(4):812-825.
  • Albain KS, Barlow WE, Shak S, et al. Prognostic and predictive value of the 21-gene recurrence score assay in postmenopausal women with node-positive, estrogen-receptor-positive breast cancer on chemotherapy: a retrospective analysis of a randomised trial. Lancet Oncol. 2010;11(1):55-65.
  • Breast cancer. National Comprehensive Cancer Network. 2018. https://www.nccn.org/professionals/physician_gls/pdf/breast.pdf Accessed September 14, 2018.

• Overview:
  • Type I (immediate) hypersensitivity:
    • Is the classic IgE – mediated allergic reaction
  • Sensitized individuals produce allergen – specific IgE:
    • That binds to FcεRI receptors on mast cells and basophils:
      • On re-exposure, cross-linking of IgE:
        • Triggers rapid release of pre-formed mediators and synthesis of secondary mediators:
          • Producing the acute allergic response

• Key Chemical Mediators:
  • Histamine:
    • Source:
      • Mast cells (tissue)
      • Basophils (blood)
    • Actions: 
      • Vasodilation
      • Increased vascular permeability:
        • Leading to tissue edema and post-capillary venule leakage
      • Smooth-muscle contraction:
        • Bronchospasm
      • Pruritus
  • Bradykinin:
    • Formation: 
      • Generated from high-molecular-weight kininogen by kallikrein
    • Actions: 
      • Peripheral vasodilation
      • Marked increase in vascular permeability
      • Pain
      • Pulmonary vasoconstriction
      • Bronchoconstriction
    • Clinical link: 
      • Major mediator of hereditary or ACE-inhibitor – induced angioedema.
  • Leukotrienes (C₄, D₄, E₄):
    • Potent, sustained bronchoconstrictors
    • Increase vascular permeability
    • Promote mucus secretion
  • Prostaglandin D₂ and platelet-activating factor:
    • Contribute to vasodilation, bronchospasm, and recruitment of inflammatory cells
• Regulation by ACE:
  • Angiotensin-converting enzyme (ACE):
    • Highly expressed on pulmonary and endothelial surfaces
    • Inactivates bradykinin and other kinins,:
      • Limiting edema
    • ACE inhibition (e.g., by ACE-inhibitor medications):
      • Elevates bradykinin levels:
        • Predisposing to angioedema with airway compromise
• Clinical Correlates:
  • Immediate phase (minutes): 
    • Mast-cell histamine release → urticaria, bronchospasm, hypotension (anaphylaxis)
  • Late phase (hours): 
    • Cytokine and leukotriene–driven influx of eosinophils and neutrophils:
      • Sustained inflammation (e.g., asthma exacerbation)
• Key Takeaway:
  • Type I hypersensitivity hinges on IgE-primed mast cells and basophils as the principal histamine sources:
    • With histamine as the rapid primary effector
  • Bradykinin amplifies vascular leakage and pain but is normally curtailed by ACE:
    • Impaired degradation (e.g., ACE-inhibitor therapy) can precipitate angioedema independent of histamine

• Design:
  • Phase III, 891 analyzable patients with stage III to IV HNSCC randomized to:
    • Accelerated RT + cisplatin (100 mg / m² D1 and D22) with or without cetuximab (400 mg / m² load then 250 mg / m² weekly)
  • Primary endpoint: 
    • PFS
      • The Cancer Imaging Archive (TCIA)+1
• Result (no efficacy gain, more acute toxicity):
  • 3-yr PFS: 
    • 61.2% (CRT) vs 58.9% (CRT + cetuximab), P = 0.76
  • 3-yr OS: 
    • 72.9% vs 75.8%, P = 0.32
  • LRC:
    • No difference
  • DM:
    • No difference
  • Treatment delivery: 
    • Similar cisplatin given (mean 191.1 vs 185.7 mg / m²):
      • But more RT interruptions with cetuximab (26.9% vs 15.1%). PubMed
  • Toxicity signal:
    • Higher grade 3 to 4 mucositis (33% vs 43%), skin reactions (in- and out-of-field), fatigue, anorexia, and hypokalemia with the triplet
    • Late grade ≥ 3 toxicity not increased PubMed+1
• Biomarkers / subgroups:
  • p16+ OPSCC had better outcomes overall:
    • But no benefit from adding cetuximab (no predictive effect)
  • EGFR expression:
    • Did not distinguish outcomes:
      • An age interaction noted in exploratory analysis is not practice-changing PubMed
• Exam / clinic pearl:
  • Do not “stack” an EGFR inhibitor onto standard cisplatin – CRT:
    • No improvement in OS / PFS / LRC and more acute toxicity
  • If a patient is cisplatin-ineligible:
    • Switch the partner (e.g., RT+cetuximab):
      • But don’t add cetuximab to cisplatin PubMed
• References:
  • Ang KK, et al. JCO 2014 (RTOG 0522) — primary results. PubMed
  • Caudell JJ, et al. 2022/2023 long-term update — confirms lack of benefit. PMC+1
  • ASCO Post 2014 — toxicity details summary. ascopost.com
  • RTOG 0522 protocol — regimen specifics. The Cancer Imaging Archive (TCIA)+1
• Bottom line: 
  • Adding cetuximab to cisplatin – CRT:
    • Does not help and harms tolerability:
      • Reserve cetuximab as an alternative when cisplatin cannot be given

• Where we are now (2025):
  • In carefully selected cT1 to cT2, cN0 patients with negative pre-op axillary US:
    • Omitting SLNB is non-inferior to SLNB for disease endpoints and reduces arm morbidity:
      • SOUND Trial , INSEMA Trial; endorsed in ASCO 2025
  • If SLN is positive (≤ 2 nodes) after lumpectomy + WBRT:
    • Omit ALND (ACSOG Z0011, 10-yr)
  • For micrometastases:
    • IBCSG 23-01 supports no ALND
  • AMAROS:
    • Axillary RT ≈ ALND for control with less lymphedema
  • Post-NAC cN1→cN0:
    • SLNB / TAD feasible if you remove the clipped node, use dual tracers, and retrieve ≥2–3 SLNs:
      • Lower FNR:
        • ACSOG Z1071 / SENTINA / SN-FNAC
  • Persistent cN+ → ALND
  • Radiation interfaces (2025 ASTRO-ASCO-SSO PMRT update) – Clarify when RNI / PMRT substitutes for completion ALND after positive SLN, and after NAC:
    • What de-escalation buys you:
      • Meaningfully less lymphedema and arm morbidity:
        • AMAROS 5-year lymphedema: 23% ALND vs 11% axillary RT; SLNB is lower still; omission (SOUND / INSEMA) lowest
        • INSEMA: omission vs SLNB—lower arm symptoms; 5-yr iDFS 91.9% vs 91.7% (HR 0.91; NI met). 
• Trial data:
  • Upfront surgery, cN0:
    • SOUND (JAMA Oncol 2023) – negative axillary US, tumor ≤ 2 cm
      • Design: SLNB vs no axillary surgery
      • Outcome: Non-inferior 5-yr distant DFS
      • Omission safe when nodal information won’t alter plan
      • Multinational, 18 centers (Italy / Spain / Switzerland / Chile)
    • INSEMA (NEJM 2025) – mostly BCS, cT1 to 2 cN0
      • Primary: 5-yr iDFS non-inferiority met (No axillary surgery 91.9% vs SLNB 91.7%; HR 0.91 [0.73–1.14])
      • OS ~ 98% vs 97%
      • Less arm morbidity if omitted
  • ASCO 2025 SLNB guideline update:
    • Allows omission of routine SLNB in selected stage I to II patients: ≥ 50 y, HR+ / HER2−, ≤ 2 cm, G1 to G2, negative axillary imaging, BCS + adjuvant therapy, and when nodal status won’t change systemic / RT
      • Shared decision-making emphasized
    • Limited SLN positivity (upfront):
      • ACSOG Z0011 (10-yr) – lumpectomy + WBRT, 1 to 2 positive SLN
        • 10-yr OS: 86.3% SLNB-alone vs 83.6% ALND
        • Regional failures < 1%
        • ALND not routine recommended 
      • IBCSG 23-01 (10-yr) – SLN micromets ≤ 2 mm:
        • No difference DFS; non-inferior to omit ALND
        • Axillary recurrences ~ 1.7% without cALND at 10 yrs
      • AMAROS – SLN+ randomized to ALND vs axillary RT:
        • Comparable control
        • Less lymphedema with RT (≈ 11% vs 23% at 5 yrs)
        • Consider RT instead of ALND
      • Neoadjuvant setting:
        • Z1071 / SENTINA / SN-FNAC – initially cN1→NAC→ycN0
        • FNR reduced by: clip + retrieve positive node (TAD), dual tracer, and retrieving ≥ 2 to 3 SLNs
        • If still cN+, ALND remains standard.
      • Radiation guidance (2025)
        • ASTRO-ASCO-SSO PMRT update (2025)
          Clarifies PMRT / RNI after upfront surgery and after NAC
        • Indicates when axillary RT is reasonable alternative to ALND in select SLN+ scenarios
        • Encourages moderate hypofractionation, details target volumes/boost
  • Practical algorithms (evidence-based):
    • Upfront cN0 (exam + negative axillary US):
      • Meets ASCO 2025 “omission” profile (≥ 50, HR+ / HER2−, ≤ 2 cm, G1 to G2) and BCS planned → Discuss omitting SLNB (SOUND Trial /INSEMA Trial) 
      • Not low-risk or mastectomy planned → SLNB (can later omit ALND depending on path)
    • SLNB results (upfront surgery):
      • 0 nodes+ → No further axillary surgery
      • 1 to 2 nodes+, lumpectomy + WBRT → Omit ALND (Z0011) or Axillary RT (AMAROS) if nodal coverage desired
      • Micromets (≤ 2 mm) → No ALND (IBCSG 23-01)
      • > 2 nodes+, gross ENE, no RT planned /possible, inflammatory BC, or T3 / T4 → ALND (plus consider RNI / PMRT)
    • NAC pathway:
      • Biopsy-proven cN1 → Clip positive node pre-NAC:
        • ycN0 after NAC → TAD (SLNB + clipped node removal) using dual tracer, aim ≥ 2 to 3 SLNs
        • If any positive or clip not retrieved, strong consideration for ALND (or RNI per MDT)
      • ycN+ → ALND (then RNI per PMRT guideline)
  • Numbers and pearls slide:
    • INSEMA:
      • 5-yearr iDFS 91.9% (omit) vs 91.7% (SLNB); HR 0.91 (NI met)
      • Lower arm morbidity with omission
    • SOUND:
      • Negative US + small tumors → no axillary surgery non-inferior to SLNB for distant DFS at 5 yrs
    • Z0011 (10-yr):
      • OS 86.3% SLNB-alone vs 83.6% ALND; regional recurrence < 1%
    • IBCSG 23-01 (10-yr):
      • Micromets – no ALND
      • Axillary recurrence ≈ 1.7% without cALND
    • AMAROS:
      • Lymphedema 23% ALND vs 11% axillary RT (5 yrs)
      • Similar control
    • Post-NAC accuracy:
      • TAD + dual tracer + ≥ 2 to 3 SLNs lowers FNR (vs SLNB alone)
    • ASTRO-ASCO-SSO 2025 PMRT:
      • When SLN+ and no ALND, RNI/PMRT often appropriate; specifics by burden / response 
• Review Questions:
• Can I omit SLNB in a 62-year-old, HR+ / HER2−, 1.3 cm IDC, negative axillary US, BCS?
  • Yes, option to omit per ASCO 2025 (criteria met) informed by SOUND and INSEMA; confirm that nodal information won’t change systemic / RT plan
• What if the same patient is having a mastectomy
  • Generally perform SLNB (you lose SLNB opportunity later; pathology could upstage; influences RNI / PMRT)
• Patient with 2 SLN+ undergoing lumpectomy – ALND or RT?
  • No routine ALND (Z0011)
  • Consider axillary RT (AMAROS) if you want nodal coverage with less lymphedema than ALND
• Post-NAC cN1→ycN0 – how do I minimize FNR?
  • Do TAD: clip and retrieve the index node, dual tracers, retrieve ≥ 2 to 3 SLNs
  • If clip not found or any positive nodes → ALND (or RNI per MDT)
• Which patients still truly need ALND today
  • Inflammatory BC
  • Persistent cN+ after NAC
  • > 2 SLN+ upfront
  • Gross ENE
  • When WBRT / RNI not feasible but regional control is required
• How do the new PMRT guidelines affect axillary surgery choices?
  • 2025 ASTRO-ASCO-SSO:
    • Clearer indications for RNI / PMRT after upfront surgery and after NAC
    • Can replace ALND in select SLN+ cases – coordinate with radiation oncology
      
      
      
      
       
       

• Rule of Thumb:
  • Avoid cisplatin in patients with grade ≥ 2 baseline hearing loss 
• Cisplatin:
  • Is ototoxic and can cause irreversible worsening of SNHL:
    • Risk is cumulative and dose-dependent
• Alternatives:
  • Cetuximab + Radiotherapy (RT):
    • NCCN-endorsed option for cisplatin-ineligible patients
    • Inferior to cisplatin in HPV-positive disease:
      • RTOG-1016, De-ESCALaTE trials:
        • But appropriate when platinum is contraindicated
• Carboplatin-based chemoradiation:
  • Some centers use carboplatin (AUC 1 to 2 weekly) ± 5-FU or paclitaxel with RT:
    • Evidence less robust than cisplatin:
      • But can be considered when cetuximab is unsuitable
• Practice Pearls:
  • Baseline audiogram required in all patients before starting cisplatin or alternatives
  • Avoid concurrent ototoxic drugs:
    • Loop diuretics, aminoglycosides, high-dose salicylates
  • Monitor hearing during therapy if any platinum agent is considered
• References:
  • NCCN Clinical Practice Guidelines in Oncology: Head and Neck Cancers, Version 2025.
  • Ahn MJ, D’Cruz A, Vermorken JB, et al. Eligibility criteria for cisplatin in head and neck cancer: consensus recommendations. Lancet Oncol. 2016;17(8):e447–e456.
  • Gillison ML, Trotti AM, Harris J, et al. Radiotherapy plus cetuximab or cisplatin in HPV-positive oropharyngeal cancer (RTOG-1016). Lancet. 2019;393:40–50.
  • Mehanna H, et al. Radiotherapy plus cisplatin or cetuximab in low-risk HPV-positive oropharyngeal cancer (De-ESCALaTE). Lancet. 2019;393:51–60.

Bottom line: In carefully selected patients (typically older, ER+/HER2–, node-negative, small tumors on endocrine therapy), skipping whole-breast radiotherapy (RT) raises local recurrence modestly but does not worsen overall survival in long-term randomized data. 

Key randomized signals (10-year):

• PRIME II (age ≥65, HR+, ≤3 cm, node-negative, endocrine therapy): local recurrence 9.5% without RT vs 0.9% with RT; no difference in distant recurrence or overall survival (~81% both arms). 

• CALGB 9343 (age ≥70, T1N0 ER+): local/regional control higher with RT (98% vs 90%) but no differences in time to mastectomy, distant metastasis, breast cancer-specific survival, or OS (67% vs 66%). 

Meta-analytic perspective: Syntheses focused on randomized trials consistently show RT substantially lowers local recurrence after breast-conserving surgery, with minimal or no OS impact in these low-risk cohorts—informing shared decisions when a patient prioritizes avoiding RT toxicity or logistics. 

Who may be appropriate to consider for omission?

• Age ≥65–70, ER+, HER2–, pT1, node-negative, clear margins, committed to endocrine therapy; ideally with a reassuring axillary assessment and low-risk biology. (Emerging prospective cohorts like LUMINA/IDEA support expanding biologic selection but are not RCTs.) 

Why this matters for patients:

• Fewer visits, less fatigue/dermatitis, and lower long-term toxicity burden—without sacrificing survival in the right subset. 

Practical takeaways for clinic:

Discuss omission for the classic low-risk profile above; quote absolute local-recurrence trade-offs (e.g., ~9–10% vs ~1% at 10 years in PRIME II).  If RT is preferred or biology is borderline, consider de-escalated RT (partial-breast or 5-fraction regimens) to cut burden while preserving control.  Use shared decision-making; align with patient goals, comorbidity, adherence to endocrine therapy, and imaging/pathology risk features. 

#BreastCancer #RadiationOncology #Deescalation #SharedDecisionMaking #Oncology

#Arrangoiz

• When to omit SLNB (new, practice-changing):
  • ASCO now recommends not performing routine SLNB in a clearly defined low-risk subgroup if omitting nodal pathology will not change adjuvant plans:
    • Postmenopausal:
      • ≥ 50 years
    • HR-positive / HER2-negative
    • Grade 1 to 2
    • Tumor ≤ 2 cm (cT1)
    • Pre-op axillary ultrasound negative
    • Breast-conserving therapy planned
    • Team agrees systemic therapy and RT will not be altered by SLNB findings:
  • Recommendation built on SOUND and INSEMA randomized trials:
    • Observed outcomes in the RCTs:
      • Omission was non-inferior to SLNB for iDFS / distant DFS
      • Regional events were rare
      • Arm morbidity lower without surgery
  • ASCO also emphasizes:
    • Do not escalate or alter adjuvant systemic therapy or radiation just because SLNB was omitted:
      • Plan treatments as you would for this low-risk profile
• When SLNB is still appropriate:
  • Outside the narrow “omit” criteria above:
    • >2 cm
    • High-grade
    • TNBC
    • HER2+
    • Multifocality affecting RT fields
    • No reliable AUS
    • Planned mastectomy where nodal information might change PMRT
  • After neoadjuvant therapy:
    • Initially cN0 or cN1→cN0:
      • ASCO continues to support SLNB (or targeted axillary dissection when appropriate) to document response:
        • The 2025 update centers on upfront surgery, don’t generalize omission to neoadjuvant settings
• When to omit completion ALND:
  • 1 to 2 positive sentinel nodes after upfront surgery:
    • Continue to omit ALND with whole-breast RT (Z0011 / AMAROS era practice remains)
  • After mastectomy with 1 to 2 positive SNs and delivery of PMRT to chest wall + regional nodes:
    • ASCO supports omitting ALND (supported by SENOMAC data):
      • Coordinate fields with radiation oncology
• Radiation interface (2025 ASTRO / ASCO / SSO PMRT update):
  • Joint 2025 PMRT guideline clarifies when PMRT / regional nodal irradiation is indicated and explicitly supports ALND omission if PMRT is given for 1 to 2 positive SNs post-mastectomy
  • Use multidisciplinary planning to balance coverage / toxicity when nodal pathology is limited or absent
• Practical checklist for your clinic (BCT, upfront surgery):
  • AUS first:
    • If AUS negative and patient fits the low-risk profile above → discuss no SLNB
    • Document that omission won’t change systemic / RT plans
  • If AUS suspicious → needle sample:
    • Positive = manage per current standards:
      • SLNB ± targeted node or ALND / RT depending on context
      • If SLNB done and 1 to 2 SN+ → omit ALND:
        • Ensure appropriate RT fields (BCT) or PMRT (after mastectomy)
  • Neoadjuvant cases:
    • Do not translate “omit SLNB” from SOUND / INSEMA:
      • Use SLNB / TAD pathways
• Pearls and Pitfalls:
  • Selection discipline matters:
    • The non-inferiority signal depends on accurate AUS triage and truly low-risk biology
  • Don’t “compensate” with extra RT or chemotherapy solely because you omitted SLNB:
    • ASCO warns against reflex escalation
  • Documentation:
    • Note eligibility criteria, shared decision discussion, and that omission won’t impact adjuvant choices
    • Monitor the edge cases (young age, lobular histology, multifocality):
      • Trials had limited power there:
        • Consider SLNB if nodal information could change RT / systemic therapy
• Sources / key reads:
  • ASCO Guideline Update (2025) — SLNB in early breast cancer; ASCO Post summary with criteria and implementation notes. 
  • INSEMA (NEJM 2025) — Omission of axillary surgery vs SLNB; non-inferior iDFS, less morbidity. 
  • SOUND (JAMA Oncol 2023) — No axillary surgery vs SLNB in small tumors with negative AUS; non-inferior distant DFS. 
  • PMRT 2025 Joint Guideline (ASTRO/ASCO/SSO) — When to deliver PMRT and how it enables ALND omission with limited SN positivity after mastectomy.