My name is Rodrigo Arrangoiz I am a breast surgeon/ thyroid surgeon / parathyroid surgeon / head and neck surgeon / surgical oncologist that works at Center for Advanced Surgical Oncology in Miami, Florida.
I was trained as a surgeon at Michigan State University from (2005 to 2010) where I was a chief resident in 2010. My surgical oncology and head and neck training was performed at the Fox Chase Cancer Center in Philadelphia from 2010 to 2012. At the same time I underwent a masters in science (Clinical research for health professionals) at the University of Drexel. Through the International Federation of Head and Neck Societies / Memorial Sloan Kettering Cancer Center I performed a two year head and neck surgery and oncology / endocrine fellowship that ended in 2016.
Mi nombre es Rodrigo Arrangoiz, soy cirujano oncólogo / cirujano de tumores de cabeza y cuello / cirujano endocrino que trabaja Center for Advanced Surgical Oncology en Miami, Florida.
Fui entrenado como cirujano en Michigan State University (2005 a 2010 ) donde fui jefe de residentes en 2010. Mi formación en oncología quirúrgica y e n tumores de cabeza y cuello se realizó en el Fox Chase Cancer Center en Filadelfia de 2010 a 2012. Al mismo tiempo, me sometí a una maestría en ciencias (investigación clínica para profesionales de la salud) en la Universidad de Drexel. A través de la Federación Internacional de Sociedades de Cabeza y Cuello / Memorial Sloan Kettering Cancer Center realicé una sub especialidad en cirugía de cabeza y cuello / cirugia endocrina de dos años que terminó en 2016.
737 patients were randomized to either undergo Halsted mastectomy or extended mastectomy with IM node dissection
After 30 years of follow-up:
There was no difference in overall survival or disease-specific survival:
For the patients eligible with T1, T2, T3, N0, and N1 disease:
Who underwent IM node dissection vs. no IM dissection
A 2019 retrospective review of 95 breast cancer patients with clinically detected IM nodes (IMNs) at diagnosis:
Were treated with surgery and radiation, with median follow-up of 43 months:
77 received neoadjuvant chemotherapy:
With IMN normalization in 67.5%
Partial IMN response in 24.6%
The 5-year IMN failure-free survival, disease-free survival, and overall survival were:
96%, 70%, and 84%, respectively
IMN failure-free survival:
Was significantly affected by:
Resection margin status
Size of IMN
Receipt of IMN boost radiation
A recently published meta-analysis in the Annals of Surgery found that axillary staging following neoadjuvant chemotherapy:
Is best performed with a combination approach of sentinel lymph node biopsy (SLNB) with excision of the pre-chemotherapy-marked positive node:
With a false negative rate of 2% to 4%:
The identification rate was 100%
ACOSOG Z1071:
Reported an overall false negative rate of 12.6% when SLNB was performed after neoadjuvant chemotherapy with documented node-positive disease prior to treatment:
The false-negative rate decreased to 6.8%:
When both sentinel node(s) and the clipped node were retrieved at the time of surgery
References:
Veronesi U, Marubini E, Mariani L, Valagussa P, Zucali R. The dissection of internal mammary nodes does not improve the survival of breast cancer patients. 30-year results of a randomised trial. Eur JCancer. 1999;35(9):1320-1325.
Kim J, Chang JS, Choi SH, et.al. Radiotherapy for initial clinically positive internal mammary nodes in breast cancer. Radiat Oncol J. 2019;37(2):91-100.
Simons JM, van Nijnatten TJA, van der Pol CC, Luiten EJT, Koppert LB, Smidt ML. Diagnostic accuracy of different surgical procedures for axillary staging after neoadjuvant systemic therapy in node-positive breast cancer: a systematic review and meta-analysis. Ann Surg. 2019;269(3):432-442.
Boughey JC, Ballman KV, Le-Petross HT, et al. Identification and resection of clipped node decreases the false-negative rate of sentinel lymph node surgery in patients presenting with nodepositive breast cancer (T0-T4, N1-N2) who receive neoadjuvant chemotherapy: results from ACOSOG Z1071 (Alliance). Ann Surg. 2016;263(5):802-807.
Arterial Anatomy of the Breast – A Practical Summary for Breast Surgeons
Understanding the arterial supply of the breast is essential for:
Oncologic resections
Reconstructive planning
Oncoplastic surgery
Complication avoidance
The breast receives a rich, redundant blood supply primarily from branches of the:
Subclavian and axillary arterial systems:
Which explains its generally good healing capacity:
But also the risk of bleeding if anatomy is not respected
Primary Arterial Sources:
Internal Mammary (Internal Thoracic) Artery:
Most important medial blood supply to the breast
Arises from the:
Subclavian artery
Gives rise to anterior intercostal perforators, especially:
2nd to 4th intercostal perforators:
Dominant contributors
Supplies:
Medial breast
Retroareolar complex
Key surgical relevance:
Critical during medial lumpectomies
Important for nipple-areolar complex (NAC) viability
Used as recipient vessels in free flap breast reconstruction
Lateral Thoracic Artery:
Branch of the axillary artery
Runs along the lateral chest wall
Supplies:
Lateral breast
Skin and glandular tissue
Key surgical relevance:
At risk during axillary dissection
Important contributor in lateral oncoplastic flaps
Thoracoacromial Artery (Pectoral Branch):
Branch of the axillary artery Supplies:
Upper outer quadrant
Pectoralis major muscle
Key surgical relevance:
Important during subpectoral dissection:
Preservation helps reduce skin flap ischemia
Posterior Intercostal Arteries:
Arise directly from the thoracic aorta
Provide deep perforating branches
Supply:
Deep parenchyma
Chest wall interface
Key surgical relevance:
Contribute to deep tissue perfusion
Source of bleeding during deep resections
Perforator System and Anastomoses:
The breast has an extensive subdermal and intraparenchymal anastomotic network
Major perforators:
Medial (internal mammary)
Lateral (lateral thoracic)
Clinical implications:
Explains tolerance of wide local excisions
Allows for oncoplastic rearrangements
Supports skin- and nipple-sparing mastectomy when flaps are well designed
Surgical Implications for Breast Surgeons:
Breast-Conserving Surgery:
Medial tumors:
Respect internal mammary perforators
Lateral tumors:
Anticipate supply from lateral thoracic artery
Mastectomy (Skin- or Nipple-Sparing):
Preserve:
Subdermal plexus
Medial perforators
Excessive cautery near the NAC increases ischemia risk
Oncoplastic Surgery:
Knowledge of arterial territories guides:
Pedicle choice
Flap orientation
Central and medial pedicles rely heavily on internal mammary perforators
Reconstruction:
Internal mammary vessels are preferred recipient vessels for free flaps
Axillary system preservation is important in implant-based reconstruction
Key Take-Home Points:
Breast arterial supply is dual and redundant, centered on:
Internal mammary system (medial dominance)
Axillary system (lateral dominance)
2nd to 4th internal mammary perforators are the most critical vessels
Surgical planning should always consider vascular territories, especially in:
Re-operations
Radiation-treated breasts
Large resections or complex oncoplastic cases
References:
Arterial Anatomy of the Breast
Cunningham L.The anatomy of the arteries and veins of the breast. J Surg Oncol. 1977;9(1):71–85. → Classic anatomic description of breast vascular supply.
Salmon RJ. Vascularization of the breast and implications for surgery. Surg Clin North Am. 1990;70(4):877–885. → Foundational surgical anatomy review.
Hall-Findlay EJ. Breast anatomy and vascular supply. Clin Plast Surg. 2002;29(3):371–384. → Highly cited reference for oncoplastic and reconstructive surgery.
Sappey M.Traité d’Anatomie Descriptive. Paris: Delahaye; 1874. → Early detailed descriptions of breast perforators (historical reference).
Taylor GI, Palmer JH. The vascular territories (angiosomes) of the body. Br J Plast Surg. 1987;40(2):113–141. → Angiosome concept applied to breast perfusion and flap design.
Internal Mammary & Perforator Anatomy:
Cormack GC, Lamberty BG. The arterial anatomy of skin flaps. Edinburgh: Churchill Livingstone; 1994. → Describes internal mammary perforators relevant to breast surgery.
Saint-Cyr M, Wong C, Schaverien M, et al. Perforator flaps: anatomy, technique, and clinical applications. Plast Reconstr Surg. 2009;124(1 Suppl):e1–e17. → Detailed perforator anatomy with relevance to NAC perfusion.
Hamdi M, Van Landuyt K, Monstrey S, Blondeel P. Pedicled perforator flaps in breast reconstruction. Semin Plast Surg. 2006;20(2):73–83.
Surgical & Oncoplastic Relevance:
Losken A, Hamdi M. Partial breast reconstruction: current perspectives. Plast Reconstr Surg. 2009;124(3):722–736. → Links vascular anatomy to oncoplastic pedicle choice.
Clough KB, Kaufman GJ, Nos C, Buccimazza I, Sarfati IM. Improving breast cancer surgery: a classification and quadrant-based approach. Plast Reconstr Surg. 2010;125(2):418–428.
Mast BA. Breast reduction and mastopexy: pedicle selection and vascular considerations. Clin Plast Surg. 1996;23(3):567–576.
Nipple–Areolar Complex (NAC) Perfusion
van Deventer PV, Graewe FR. Blood supply of the nipple–areolar complex. Plast Reconstr Surg. 1984;74(4):499–504.
Russo V, Della Corte A, et al. Nipple–areola complex vascular anatomy and surgical implications. Aesthetic Plast Surg. 2017;41(2):267–274.
Reconstruction-Focused References:
Blondeel PN, Morris SF, Hallock GG, Neligan PC.Perforator Flaps: Anatomy, Technique, and Clinical Applications. St. Louis: Quality Medical Publishing; 2006.
Nahabedian MY. Breast reconstruction and internal mammary vessels. Plast Reconstr Surg. 2012;130(4):883–891.
What was the primary research question of the INSEMA trial?
Answer:
To determine whether sentinel lymph node biopsy (SLNB) can be safely omitted in patients with clinically node-negative early-stage breast cancer undergoing breast-conserving surgery and whole breast radiation, without compromising invasive disease-free survival (iDFS)
What type of study was this, and how was it designed?
Answer:
It was a prospective, randomized, multicenter, non-inferiority trial conducted in Germany and Austria
Patients were randomized in a 4:1 ratio to no SLNB vs. SLNB
What were the eligibility criteria for patients to be included in the trial?
Answer:
Female patients
Clinically node-negative (cN0) invasive breast cancer
Tumor size cT1 to cT2 (≤ 5 cm)
Candidates for breast-conserving surgery and whole-breast irradiation
No prior axillary surgery, neoadjuvant therapy, or mastectomy
What was the primary endpoint, and what was the non-inferiority margin?
Answer:
Primary endpoint:
5-year invasive disease-free survival (iDFS)
Non-inferiority margin:
Hazard Ratio upper limit of 1.271 and ≥ 85% iDFS in the no-SLNB arm
What were the main results regarding iDFS
Answer:
iDFS: 91.9% (no-SLNB) vs. 91.7% (SLNB)
HR: 0.91 (95% CI, 0.73–1.14) → Non-inferiority was met
Was there a difference in overall survival (OS)
Answer:
Yes, but it favored no-SLNB slightly:
5-year OS: 98.2% (no-SLNB) vs. 96.9% (SLNB):
Difference was not statistically significant
What was the axillary recurrence rate in both groups?
Answer:
No-SLNB: 1.0%
SLNB: 0.3%
While slightly higher in the no-SLNB group:
Both rates were very low and clinically acceptable
What secondary outcomes were assessed?
Answer:
Lymphedema incidence
Arm / shoulder function and pain
Quality of life
All significantly favored the no-SLNB group
What are the main clinical implications of this study?
Answer:
In selected low-risk patients:
SLNB may be safely omitted:
Reducing surgical morbidity and improving quality of life without compromising survival
Which subgroup of patients benefits most from SLNB omission based on this trial?
Answer:
Women ≥ 50 years old with T1, grade 1 to grade 2, hormone receptor-positive, HER2-negative tumors undergoing lumpectomy with whole breast radiation
Can we apply the findings of this trial to patients undergoing mastectomy or partial-breast irradiation?
Answer:
No:
Those patients were excluded, so the results cannot be extrapolated to those scenarios
How might omitting SLNB affect adjuvant therapy decisions?
Answer:
Without nodal staging, decisions about chemotherapy or genomic testing might become more challenging:
Multidisciplinary evaluation is essential
How do these findings compare to axillary de-escalation trends seen in trials like ACOSOG Z0011 or SOUND?
Answer:
Similar direction:
All support less axillary surgery in low-risk, clinically node-negative patients
INSEMA takes it a step further by testing omission of SLNB itself
What are some limitations of the INSEMA trial
Answer:
Limited generalizability:
Mostly postmenopausal, low-risk tumors
Exclusion of higher-risk patients:
HER2+, triple-negative, T2 > 3 cm
Lack of data in mastectomy or neoadjuvant settings
If one of your patients meets criteria from this trial, how would you counsel them on omitting SLNB?
Answer:
Explain that in select low-risk early-stage breast cancer, omitting SLNB does not affect survival, reduces the risk of complications like lymphedema, and improves quality of life:
However, thorough discussion with oncology and radiation teams is important to individualize care
Refers to the delivery of systemic treatment prior to surgery
Preoperative chemotherapy:
Was initially utilized in women with locally advanced or inflammatory cancers:
To improve operability
Among women with early-stage breast cancers, the NSABP B-18 and B-27 randomized clinical trials:
Demonstrated no difference in disease-specific or overall survival:
Between those who received neoadjuvant versus adjuvant chemotherapy
Neoadjuvant chemotherapy improved rates of breast conservation:
68% versus 60%
More recent observational data:
Have demonstrated no increased risk in surgical complications among women who underwent neoadjuvant chemotherapy
NAC has more recently been used to:
Downstage the axilla in patients with biopsy proven lymph node involvement with hopes to avoid completion lymphadenectomy and decrease the risk of lymphedema. Additionally, NAC has been used in women with operable breast cancers to theoretically treat micrometastatic disease prior to local therapy and to allow assessment of the in vivo tumor response to certain chemotherapy regimens.
Notably, results from the Early Breast Cancer Trialists’ Collaborative Group (EBCTCG) meta-analysis3 included patient-level data from 4,756 women enrolled in clinical trials 1983-2002; results demonstrated a higher risk of in-breast recurrence after neoadjuvant chemotherapy. At 15 years, women treated with NAC had a 21% risk of local recurrence (vs. 16% in the surgery-first patients). This was attributed to a higher rate of breast conservation, but with no difference in distant recurrence or breast cancer-specific overall survival.3
References
1. Fisher B, Bryant J, Wolmark N, Mamounas E, Brown A, Fisher ER, et al. Effect of preoperative chemotherapy on the outcome of women with operable breast cancer. J Clin Oncol. 1998;16(8): 2672-2685.
2. Boughey J, Peintinger F, Meric-Bernstam F, Perry AC, Hunt KK, Babiera GV, et al. Impact of preoperative versus postoperative chemotherapy on the extent and number of surgical procedures in patients treated in randomized clinical trials for breast cancer. Ann Surg. 2006;244(3):464-470.
3. Early Breast Cancer Trialists’ Collaborative Group (EBCTCG). Long-term outcomes for neoadjuvant versus adjuvant chemotherapy in early breast cancer: meta-analysis of individual patient data from ten randomized trials. Lancet Oncol. 2018;19(1):27-39.
Substantially reduces the risk of developing invasive breast cancer in patients with lobular carcinoma in situ (LCIS) and should be offered
Negative margins are generally not required for classic LCIS:
Whereas they are recommended for:
Pleomorphic LCIS
The patient’s future risk of developing breast cancer is:
Approximately 1% annually
Bilateral prophylactic mastectomy:
Is generally considered to be more invasive than is required in this setting and, although it could be discussed as an option, should not be routinely recommended
References:
Page DL, Kidd TE Jr, Dupont WD, Simpson JF, Rogers LW. Lobular neoplasia of the breast: higher risk for subsequent invasive cancer predicted by more extensive disease. Hum Pathol. 1991;22(12):1232-1239.
Andersen JA. Lobular carcinoma in situ of the breast. An approach to rational treatment. Cancer. 1977;39(6):2597-2602.
Akashi-Tanaka S, Fukutomi T, Nanasawa T, Matsuo K, Hasegawa T, Tsuda H. Treatment of noninvasive carcinoma: fifteen-year results at the National Cancer Center Hospital in Tokyo. Breast Cancer. 2000;7(4):341-344.
Walt AJ, Simon M, Swanson GM. The continuing dilemma of lobular carcinoma in situ. Arch Surg. 1992;127(8):904-907.
Haagensen CD, Bodian C, Haagensen DE. Neoplasia (lobular carcinoma in situ). In Breast Carcinoma: Risk and Detection. Philadelphia, PA: WB Saunders, 1981.
Wong SM, King T, Boileau JF, Barry WT, Golshan M. Population-based analysis of breast cancer incidence and survival outcomes in women diagnosed with lobular carcinoma in situ. Ann Surg Oncol. 2017;24(9):2509-2517.
Fisher ER, Land SR, Fisher B, Mamounas E, Gilarski L, Wolmark N. Pathologic findings from the National Surgical Adjuvant Breast and Bowel Project: twelve-year observations concerning lobular carcinoma in situ. Cancer. 2004;100(2):238-234.
Is, by definition, a non-invasive breast malignancy confined to the ductal system:
But in a meaningful minority of cases, pathologists identify a tiny focus of invasion measuring 1 mm or less—so-called DCIS with microinvasion (DCISM)
How often does this actually happen?
The answer depends on how you frame the question.
The Short Answer:
Microinvasion is identified in roughly:
5% to 10% of all DCIS cases
DCIS with microinvasion:
Accounts for about 1% to 2% of all breast cancers (Sopik et al., Breast Cancer Research and Treatment, 2018; Zheng et al., Journal of International Medical Research, 2020)
The reported rate varies widely, however, and two very different clinical questions often get lumped together:
What proportion of diagnosed DCIS turns out to contain a microinvasive focus?
How often does a core-biopsy diagnosis of DCIS get upstaged at surgical excision?
Microinvasion Within Diagnosed DCIS:
In large surgical and pathologic series:
The numbers cluster at the lower end of the 5% to 10% range:
The UK Sloane Project (n = 11,285) recorded microinvasion in 4.6% of DCIS patients:
Though individual screening units reported rates anywhere from 0% to 25% (Shaaban et al., British Journal of Cancer, 2022)
A single-center series of 148 surgically treated DCIS cases:
Found microinvasive foci in 14.9% (Scheidegger et al., Human Pathology, 2025)
The spread largely reflects differences in how aggressively specimens are sectioned and sampled
Upstaging From Core Biopsy:
Because core-needle biopsy samples only a fraction of the lesion:
DCIS diagnosed on core biopsy is frequently “upstaged” once the whole specimen is examined:
Approximately 6.6% of core-biopsy DCIS is upstaged to microinvasive disease, and around 22% to frank invasive carcinoma:
With an overall upstaging range of 8% to 47% across studies (Walters et al., Histopathology, 2015).
A meta-analysis cited by the American College of Radiology:
Reported an overall DCIS-to-invasive upstaging rate of 25.9% (Kuzmiak et al., Journal of the American College of Radiology, 2025)
When the core biopsy already shows microinvasion:
Upstaging to measurable invasive cancer (> 1 mm) occurs in about 28% to 37%:
Yet nodal positivity remains low (~1% to 7%) (Phantana-Angkool et al., Annals of Surgical Oncology, 2019)
What Predicts Microinvasion?
Microinvasion is consistently linked to:
Higher-risk DCIS features
Independent predictors in the Sloane Project and other series include:
High nuclear grade
Large DCIS extent (≥ 2.6 cm)
Comedo necrosis
Solid / cribriform architecture
PR negativity (Shaaban et al., British Journal of Cancer, 2022; de Mascarel et al., Cancer, 2002)
Why It Matters Clinically:
Despite the “invasive” label, microinvasive disease carries a low nodal metastasis rate (roughly 2% to 6%, range 0% to 20%) and a generally favorable prognosis (Sopik et al., Breast Cancer Research and Treatment, 2018):
For this reason, management largely follows DCIS principles:
Including the DCIS margin standard of > 2 mm
That said, the Sloane Project offered an important caveat:
Compared with pure DCIS, microinvasive disease was associated with:
Higher distant metastasis (1.2% vs 0.3%) and higher breast cancer mortality (2.1% vs 0.8%):
Suggesting more aggressive biology in a subset of patients (Shaaban et al., British Journal of Cancer, 2022)
The Takeaway for Readers:
“Incidence of microinvasion in DCIS” is best answered with a range—about 5% to 10% of diagnosed DCIS:
Nearer 5% in rigorously standardized series, while keeping the separate upstaging question in mind when counseling patients after a core-biopsy diagnosis
