Sentinel lymph node biopsy US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Sentinel lymph node biopsy. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Sentinel lymph node biopsy US Medical PG Question 1: A 49-year-old woman presents to her physician with complaints of breast swelling and redness of the skin over her right breast for the past 1 month. She also mentions that the skin above her right breast appears to have thickened. She denies any pain or nipple discharge. The past medical history is significant for a total abdominal hysterectomy at 45 years of age. Her last mammogram 1 year ago was negative for any pathologic changes. On examination, the right breast was diffusely erythematous with gross edema and tenderness and appeared larger than the left breast. The right nipple was retracted and the right breast was warmer than the left breast. No localized mass was palpated. Which of the following statements best describes the patient’s most likely condition?
- A. It shows predominant lymphatic spread.
- B. The lesion expresses receptors for estrogen and progesterone.
- C. The lesion is due to Streptococcal infection.
- D. It is a benign lesion.
- E. The inflammation is due to obstruction of dermal lymphatic vessels. (Correct Answer)
Sentinel lymph node biopsy Explanation: ***The inflammation is due to obstruction of dermal lymphatic vessels.***
- The presentation of **rapid-onset breast swelling, redness, thickening of the skin, warmth, and nipple retraction** without a palpable mass is highly suggestive of **inflammatory breast cancer (IBC)**.
- IBC is characterized by the **obstruction of dermal lymphatic vessels by tumor cells**, leading to the classic inflammatory signs and **peau d'orange** appearance.
*It shows predominant lymphatic spread.*
- While IBC does involve **lymphatic spread**, this statement alone does not fully encompass the characteristic pathology of the condition causing the observed symptoms.
- The obstruction of the **dermal lymphatic vessels** is a more precise description of the immediate cause of the clinical presentation.
*The lesion expresses receptors for estrogen and progesterone.*
- Although some breast cancers are **hormone receptor-positive (ER/PR positive)**, there is no direct information in the vignette to suggest this specificity for the patient's condition.
- This statement refers to a **molecular characteristic** that is not a defining feature of the clinical presentation of IBC.
*The lesion is due to Streptococcal infection.*
- While a **bacterial infection** (like **streptococcal cellulitis**) can cause redness, swelling, and warmth, it typically presents with more acute symptoms, fever, and often a clearer response to antibiotics.
- The **thickening of the skin** and **nipple retraction** point away from a simple infection and towards a malignant process.
*It is a benign lesion.*
- The rapid progression of symptoms, pronounced skin changes, and nipple retraction are all **red flags for malignancy**, specifically inflammatory breast cancer.
- **Benign lesions** rarely cause such diffuse, severe, and rapidly progressing inflammatory signs.
Sentinel lymph node biopsy US Medical PG Question 2: A 64-year-old woman presents to the surgical oncology clinic as a new patient for evaluation of recently diagnosed breast cancer. She has a medical history of type 2 diabetes mellitus for which she takes metformin. Her surgical history is a total knee arthroplasty 7 years ago. Her family history is insignificant. Physical examination is notable for an irregular nodule near the surface of her right breast. Her primary concern today is which surgical approach will be chosen to remove her breast cancer. Which of the following procedures involves the removal of a portion of a breast?
- A. Arthroplasty
- B. Lumpectomy (Correct Answer)
- C. Vasectomy
- D. Mastectomy
- E. Laminectomy
Sentinel lymph node biopsy Explanation: ***Lumpectomy***
- A **lumpectomy** is a surgical procedure that removes the **breast cancer tumor** and a small margin of surrounding healthy tissue, preserving most of the breast.
- This procedure is a common treatment for early-stage breast cancer and is often followed by radiation therapy.
*Arthroplasty*
- **Arthroplasty** is a surgical procedure to **repair or replace a joint**, typically due to arthritis or injury.
- The patient's history of a total knee arthroplasty indicates this procedure was performed on her knee, not her breast.
*Vasectomy*
- A **vasectomy** is a surgical procedure for **male sterilization**, involving the cutting and sealing of the vas deferens.
- This procedure is unrelated to breast cancer treatment or breast surgery.
*Mastectomy*
- A **mastectomy** involves the **complete surgical removal of the entire breast**, often including the nipple and areola.
- While it is a breast surgery, it removes the *entire* breast, not just a portion.
*Laminectomy*
- A **laminectomy** is a surgical procedure that removes a portion of the **vertebra (lamina)** to relieve pressure on the spinal cord or nerves.
- This procedure is for spinal conditions and is entirely unrelated to breast cancer surgery.
Sentinel lymph node biopsy US Medical PG Question 3: The patient undergoes a mammogram, which shows a 6.5mm sized mass with an irregular border and spiculated margins. A subsequent core needle biopsy of the mass shows infiltrating ductal carcinoma with HER2-positive, estrogen-negative, and progesterone-negative immunohistochemistry staining. Blood counts and liver function tests are normal. Laboratory studies show:
Hemoglobin 12.5 g/dL
Serum
Na+ 140 mEq/L
Cl- 103 mEq/L
K+ 4.2 mEq/L
HCO3- 26 mEq/L
Ca2+ 8.9 mg/dL
Urea Nitrogen 12 mg/dL
Glucose 110 mg/dL
Alkaline Phosphatase 25 U/L
Alanine aminotransferase (ALT) 15 U/L
Aspartate aminotransferase (AST) 13 U/L
Which of the following is the most appropriate next step in management?
- A. Breast-conserving therapy and sentinel lymph node biopsy (Correct Answer)
- B. Bilateral mastectomy with lymph node dissection
- C. Trastuzumab therapy
- D. Bone scan
- E. Whole-body PET/CT
Sentinel lymph node biopsy Explanation: ***Breast-conserving therapy and sentinel lymph node biopsy***
- The patient has **early-stage (T1) breast cancer** (6.5mm mass), which is amenable to **breast-conserving therapy (lumpectomy)** as the primary surgical approach.
- A **sentinel lymph node biopsy** is essential to determine nodal status and guide further staging and adjuvant therapy, as the tumor size does not preclude nodal involvement.
*Bilateral mastectomy with lymph node dissection*
- This is an **overly aggressive surgical approach** for a small, unifocal tumor without evidence of multifocality or significant risk factors for recurrence in the contralateral breast.
- While **axillary lymph node dissection** may be indicated if the sentinel node is positive, it is not the initial preferred approach for all patients, especially with no current evidence of nodal metastasis.
*Trastuzumab therapy*
- **Trastuzumab** is a targeted therapy for **HER2-positive breast cancer**, but it is typically administered as **adjuvant therapy** (after surgery) or neoadjuvant therapy (before surgery).
- It is not the most appropriate *initial* next step before surgical management and comprehensive staging have been completed.
*Bone scan*
- A **bone scan** is used to detect **bone metastases**, but it is generally reserved for patients with **advanced-stage cancer** (e.g., T3/T4 tumor, N2/N3 nodes), symptoms suggestive of bony involvement, or significantly elevated alkaline phosphatase.
- Given the patient's small tumor size (6.5mm), normal labs, and lack of symptoms, a bone scan is not indicated as the *next* immediate step.
*Whole-body PET/CT*
- **Whole-body PET/CT** is primarily used for **staging advanced cancer** or investigating suspicious findings in symptomatic patients.
- For this small, early-stage breast cancer with no signs of distant metastasis indicated by normal blood tests, a PET/CT is **not recommended** as routine staging and carries unnecessary radiation exposure and cost.
Sentinel lymph node biopsy US Medical PG Question 4: A 42-year-old woman presents to the physician because of an abnormal breast biopsy report following suspicious findings on breast imaging. Other than being concerned about her report, she feels well. She has no history of any serious illnesses and takes no medications. She does not smoke. She consumes wine 1–2 times per week with dinner. There is no significant family history of breast or ovarian cancer. Vital signs are within normal limits. Physical examination shows no abnormal findings. The biopsy shows lobular carcinoma in situ (LCIS) in the left breast. Which of the following is the most appropriate next step in management?
- A. Careful observation + routine mammography (Correct Answer)
- B. Left mastectomy + axillary dissection + local irradiation
- C. Lumpectomy + routine screening
- D. Lumpectomy + breast irradiation
- E. Breast irradiation + tamoxifen
Sentinel lymph node biopsy Explanation: ***Careful observation + routine mammography***
- **Lobular carcinoma in situ (LCIS)** is considered a **non-obligate precursor** to invasive carcinoma, meaning it indicates an increased risk for developing invasive breast cancer in either breast (approximately 1-2% per year), but it is not itself invasive.
- Management typically involves **careful surveillance** with routine clinical exams and **mammography**, as this is the most appropriate initial approach for classic LCIS.
- Surgical excision is often unnecessary due to LCIS's diffuse nature and the fact that it serves as a risk marker rather than a direct precancerous lesion requiring removal.
*Left mastectomy + axillary dissection + local irradiation*
- This aggressive approach is reserved for **invasive breast cancer** and would be excessive for LCIS, which is a non-invasive lesion and a marker of increased risk rather than an immediate threat.
- **Axillary dissection** is performed to stage nodal involvement in invasive cancer, which is not applicable here as LCIS does not metastasize.
*Lumpectomy + routine screening*
- While a **lumpectomy (excision)** may be considered for **pleomorphic LCIS** or when there is diagnostic uncertainty, it is not the standard initial management for classic LCIS.
- Classic LCIS is often multifocal and bilateral, making localized excision less effective as a risk-reduction strategy.
*Lumpectomy + breast irradiation*
- **Radiation therapy** is typically used to reduce local recurrence risk after **lumpectomy for invasive breast cancer** or **ductal carcinoma in situ (DCIS)**.
- For LCIS, irradiation is generally not recommended as it is non-invasive and does not benefit from local radiation treatment.
*Breast irradiation + tamoxifen*
- **Tamoxifen** is a selective estrogen receptor modulator (SERM) that can be **offered for risk reduction** in women with LCIS, potentially reducing the risk of invasive breast cancer by approximately 50%.
- However, tamoxifen is typically discussed as an **additional preventive option** after initial diagnosis and counseling, not as the immediate next step.
- **Breast irradiation** is not indicated for LCIS, as it is non-invasive and does not require local radiation treatment, making this combination inappropriate.
Sentinel lymph node biopsy US Medical PG Question 5: A 47-year-old woman comes to the physician for a mass in her left breast she noticed 2 days ago during breast self-examination. She has hypothyroidism treated with levothyroxine. There is no family history of breast cancer. Examination shows large, moderately ptotic breasts. The mass in her left breast is small (approximately 1 cm x 0.5 cm), firm, mobile, and painless. It is located 4 cm from her nipple-areolar complex at the 7 o'clock position. There are no changes in the skin or nipple, and there is no palpable axillary adenopathy. No masses are palpable in her right breast. A urine pregnancy test is negative. Mammogram showed a soft tissue mass with poorly defined margins. Core needle biopsy confirms a low-grade infiltrating ductal carcinoma. The pathological specimen is positive for estrogen receptors and negative for progesterone and human epidermal growth factor receptor 2 (HER2) receptors. Staging shows no distant metastatic disease. Which of the following is the most appropriate next step in management?
- A. Lumpectomy with sentinel lymph node biopsy followed by hormone therapy
- B. Nipple-sparing mastectomy with axillary lymph node dissection followed by hormone therapy
- C. Nipple-sparing mastectomy with axillary lymph node dissection, followed by radiation and hormone therapy
- D. Radical mastectomy followed by hormone therapy
- E. Lumpectomy with sentinel lymph node biopsy, followed by radiation and hormone therapy (Correct Answer)
Sentinel lymph node biopsy Explanation: **Lumpectomy with sentinel lymph node biopsy, followed by radiation and hormone therapy**
- The patient has **early-stage (T1N0M0) estrogen receptor (ER)-positive, HER2-negative invasive ductal carcinoma** suitable for **breast-conserving surgery (lumpectomy)**.
- **Lumpectomy** must be followed by **radiation therapy** to the remaining breast tissue to reduce the risk of local recurrence, and **endocrine therapy** (due to ER positivity) is indicated to reduce systemic recurrence risk.
- **Sentinel lymph node biopsy** is performed to stage the axilla; if positive, an axillary lymph node dissection may be indicated. However, in this case, the mass is small, and there is no palpable axillary adenopathy, making sentinel lymph node biopsy the appropriate initial step.
*Lumpectomy with sentinel lymph node biopsy followed by hormone therapy*
- While **lumpectomy with sentinel lymph node biopsy** and **hormone therapy** are part of the appropriate management, **radiation therapy** to the conserved breast is a critical component that is missing from this option.
- Omitting **radiation therapy** after lumpectomy for invasive breast cancer significantly increases the risk of local recurrence.
*Nipple-sparing mastectomy with axillary lymph node dissection followed by hormone therapy*
- A **nipple-sparing mastectomy** is a more aggressive surgical approach than typically required for a **small, early-stage tumor** like this, which is amenable to breast-conserving surgery.
- **Axillary lymph node dissection** is usually reserved for cases with clinically positive lymph nodes or a positive sentinel lymph node biopsy, not as an initial step when there is no palpable axillary adenopathy.
*Nipple-sparing mastectomy with axillary lymph node dissection, followed by radiation and hormone therapy*
- This option involves an **unnecessarily extensive surgical procedure (nipple-sparing mastectomy with axillary lymph node dissection)** for a **small (1cm x 0.5cm) early-stage tumor** that can be managed with breast-conserving therapy.
- While radiation and hormone therapy are relevant, the initial surgical choice is too aggressive given the clinical presentation.
*Radical mastectomy followed by hormone therapy*
- **Radical mastectomy** (which includes removal of the breast, underlying chest muscle, and axillary lymph nodes) is rarely performed today due to its significant morbidity and is not indicated for this **early-stage tumor**.
- **Modified radical mastectomy**, which removes the breast and axillary lymph nodes while preserving the chest muscle, is typically only considered if breast-conserving surgery is not feasible or desired, and **hormone therapy** would be indicated, but **radiation** may also be needed depending on other factors.
Sentinel lymph node biopsy US Medical PG Question 6: A 61-year-old woman presents to a surgical oncologist for consideration of surgical removal of biopsy-confirmed breast cancer. The mass is located in the tail of Spence along the superolateral aspect of the left breast extending into the axilla. The surgical oncologist determines that the optimal treatment for this patient involves radical mastectomy including removal of the axillary lymph nodes. The patient undergoes all appropriate preoperative tests and is cleared for surgery. During the operation, multiple enlarged axillary lymph nodes are present along the superolateral chest wall. While exposing the lymph nodes, the surgeon accidentally nicks a nerve. Which of the following physical examination findings will most likely be seen in this patient following the operation?
- A. Internal rotation, adduction, and extension of the arm
- B. Weakness in arm flexion at the elbow and numbness over the lateral forearm
- C. Weakness in shoulder abduction and numbness over the lateral shoulder
- D. Scapular protrusion while pressing against a wall (Correct Answer)
- E. Weakness in wrist extension and numbness over the dorsal hand
Sentinel lymph node biopsy Explanation: ***Scapular protrusion while pressing against a wall***
- Damage to the **long thoracic nerve** during axillary dissection (common in radical mastectomy) paralyzes the **serratus anterior muscle**.
- Paralysis of the serratus anterior causes **scapular winging** (protrusion) and inability to effectively protract the scapula, especially when pushing against a wall.
*Internal rotation, adduction, and extension of the arm*
- This constellation of findings, sometimes called **"policeman's tip"**, is characteristic of an **Erb's palsy**, involving the C5-C6 roots of the brachial plexus.
- Erb's palsy typically results from birth trauma or severe shoulder injury, not commonly from axillary lymph node dissection.
*Weakness in arm flexion at the elbow and numbness over the lateral forearm*
- This symptom complex indicates injury to the **musculocutaneous nerve**, affecting the biceps brachii and brachialis muscles and sensation to the lateral forearm.
- While theoretically possible in deep axillary dissection, it is less common than long thoracic nerve injury during routine axillary node removal.
*Weakness in shoulder abduction and numbness over the lateral shoulder*
- This presentation suggests damage to the **axillary nerve**, which innervates the deltoid and teres minor muscles and provides sensation over the "regimental badge" area of the shoulder.
- The axillary nerve is located more inferiorly and posteriorly in the axilla and is less prone to injury during standard anterior axillary lymph node dissection compared to the long thoracic nerve.
*Weakness in wrist extension and numbness over the dorsal hand*
- These are signs of **radial nerve injury**, which affects the extensor muscles of the wrist and fingers and sensation over the dorsal hand.
- The radial nerve runs more posteriorly in the axilla and arm, making it less susceptible to injury during an anterior axillary lymph node dissection.
Sentinel lymph node biopsy US Medical PG Question 7: A 34-year-old Ethiopian woman who recently moved to the United States presents for evaluation to a surgical outpatient clinic with painful ulceration in her right breast for the last 2 months. She is worried because the ulcer is increasing in size. On further questioning, she says that she also has a discharge from her right nipple. She had her 2nd child 4 months ago and was breastfeeding the baby until the pain started getting worse in the past few weeks, and is now unbearable. According to her health records from Africa, her physician prescribed antimicrobials multiple times with a diagnosis of mastitis, but she did not improve significantly. Her mother and aunt died of breast cancer at 60 and 58 years of age, respectively. On examination, the right breast is enlarged and firm, with thickened skin, diffuse erythema, edema, and an ulcer measuring 3 × 3 cm. White-gray nipple discharge is present. The breast is tender with axillary and cervical adenopathy. Mammography is ordered, which shows a mass with a large area of calcifications, parenchymal distortion, and extensive soft tissue and trabecular thickening in the affected breast. The patient subsequently undergoes core-needle and full-thickness skin punch biospies. The pathology report states a clear dermal lymphatic invasion by tumor cells. Which of the following is the most likely diagnosis?
- A. Infiltrating ductal carcinoma
- B. Infiltrating lobular carcinoma
- C. Inflammatory breast cancer (Correct Answer)
- D. Ductal carcinoma in situ (DCIS)
- E. Lobular carcinoma in situ (LCIS)
Sentinel lymph node biopsy Explanation: ***Inflammatory breast cancer***
- The rapid onset of **diffuse erythema**, **edema** (peau d'orange appearance due to lymphatic involvement), **skin thickening**, ulceration, and the palpable **axillary and cervical adenopathy** are classic signs of inflammatory breast cancer.
- The mammographic findings of **parenchymal distortion**, extensive soft tissue, **trabecular thickening**, and especially the **dermal lymphatic invasion** by tumor cells on biopsy confirm this aggressive diagnosis.
*Infiltrating ductal carcinoma*
- While **infiltrating ductal carcinoma** is the most common type of breast cancer, it typically presents as a **palpable mass** or an abnormal mammogram finding without the prominent inflammatory signs seen here.
- It usually does not involve such widespread **dermal lymphatic invasion** and rapid progression with skin changes, unless it is a specific variant with inflammatory features.
*Infiltrating lobular carcinoma*
- This type of carcinoma often grows in a **diffuse pattern** and may not form a distinct mass, sometimes making it difficult to detect by mammography.
- However, it rarely presents with the prominent **inflammatory signs** (erythema, edema, skin thickening) and ulceration indicative of extensive dermal lymphatic involvement as described.
*Ductal carcinoma in situ (DCIS)*
- **DCIS** is a non-invasive form of breast cancer confined to the breast ducts, meaning it has not spread beyond the ductal basement membrane.
- It typically presents as **microcalcifications** on mammography and does not exhibit a rapidly progressing **painful ulceration**, **skin changes**, or **lymph node involvement**.
*Lobular carcinoma in situ (LCIS)*
- **LCIS** is a non-invasive condition that increases the risk of developing invasive breast cancer in either breast.
- It is an **incidental finding** on biopsy for another reason, does **not form a mass**, and does not cause the **clinical signs of inflammation**, skin changes, or ulceration.
Sentinel lymph node biopsy US Medical PG Question 8: An excisional biopsy is performed and the diagnosis of superficial spreading melanoma is confirmed. The lesion is 1.1 mm thick. Which of the following is the most appropriate next step in management?
- A. Surgical excision with 0.5-1 cm safety margins only
- B. Surgical excision with 1 cm safety margins only
- C. Surgical excision with 1-2 cm safety margins only
- D. Surgical excision with 0.5-1 cm safety margins and sentinel lymph node study
- E. Surgical excision with 1-2 cm safety margins and sentinel lymph node study (Correct Answer)
Sentinel lymph node biopsy Explanation: ***Surgical excision with 1-2 cm safety margins and sentinel lymph node study***
- A melanoma with a **Breslow thickness between 1.01 mm and 2.0 mm** (like this 1.1 mm lesion) requires a recommended surgical margin of **1 to 2 cm**.
- For melanomas **≥0.8 mm thickness** (or those with ulceration), a **sentinel lymph node biopsy (SLNB)** is recommended to assess for micrometastasis, as it helps in staging and prognosis.
*Surgical excision with 0.5-1 cm safety margins only*
- A 0.5 cm margin is typically reserved for melanoma *in situ* or extremely thin melanomas (less than or equal to 0.5 mm), and 1 cm for lesions 0.51 to 1.0 mm, which is too narrow for a 1.1 mm lesion.
- This option incorrectly omits the **sentinel lymph node study**, which is indicated for a melanoma of this thickness.
*Surgical excision with 1 cm safety margins only*
- While 1 cm is a common margin for lesions up to 1.0 mm, a 1.1 mm melanoma usually warrants a slightly wider margin, ideally 1-2 cm.
- This option also fails to include the **sentinel lymph node study**, which is crucial for staging melanomas ≥0.8 mm thickness.
*Surgical excision with 0.5-1 cm safety margins and sentinel lymph node study*
- The recommended surgical margin for a 1.1 mm melanoma is at least **1 cm, preferably between 1 and 2 cm**, making a 0.5-1 cm range insufficient.
- Although it correctly includes the sentinel lymph node study, the **surgical margin is inadequate** for the given Breslow thickness.
*Surgical excision with 1-2 cm safety margins only*
- While the **1-2 cm surgical margin** is appropriate for a 1.1 mm melanoma, this option **incorrectly excludes the sentinel lymph node study**.
- The sentinel lymph node biopsy is a critical part of the staging and management plan for melanomas of this thickness to detect potential nodal involvement.
Sentinel lymph node biopsy US Medical PG Question 9: A 50-year-old obese woman presents for a follow-up appointment regarding microcalcifications found in her left breast on a recent screening mammogram. The patient denies any recent associated symptoms. The past medical history is significant for polycystic ovarian syndrome (PCOS), for which she takes metformin. Her menarche occurred at age 11, and the patient still has regular menstrual cycles. The family history is significant for breast cancer in her mother at the age of 72. The review of systems is notable for a 6.8 kg (15 lb) weight loss in the past 2 months. The vital signs include: temperature 37.0°C (98.6°F), blood pressure 130/70 mm Hg, pulse 82/min, respiratory rate 17/min, and oxygen saturation 98% on room air. On physical examination, the patient is alert and cooperative. The breast examination reveals no palpable masses, lymphadenopathy, or evidence of skin retraction. A biopsy of the left breast is performed, and histologic examination demonstrates evidence of non-invasive malignancy. Which of the following is the most appropriate definitive treatment for this patient?
- A. Tamoxifen
- B. Observation with bilateral mammograms every 6 months
- C. Lumpectomy (Correct Answer)
- D. Radiotherapy
- E. Bilateral mastectomy
Sentinel lymph node biopsy Explanation: ***Lumpectomy***
- This patient has **non-invasive malignancy**, likely **ductal carcinoma in situ (DCIS)**, identified through microcalcifications and confirmed by excisional biopsy. For DCIS without gross invasion, the primary treatment is **surgical excision**, often a lumpectomy.
- A lumpectomy, also known as **breast-conserving surgery**, aims to remove the cancerous tissue with a margin of healthy tissue while preserving the rest of the breast.
*Tamoxifen*
- **Tamoxifen** is an **estrogen receptor modulator** used as **adjuvant therapy** for hormone-receptor-positive breast cancer, primarily after surgical removal of the tumor. It is not a primary treatment for removing the malignancy itself.
- While it might be considered after surgery depending on receptor status, it does not address the need for initial excision of the non-invasive malignancy.
*Observation with bilateral mammograms every 6 months*
- **Observation** is insufficient for confirmed non-invasive malignancy, which carries a risk of progression if untreated. **Active intervention** is required once malignancy is histologically confirmed.
- This approach might be considered for high-risk lesions or atypical hyperplasia, but not for confirmed carcinoma in situ.
*Radiotherapy*
- **Radiotherapy** is often used as **adjuvant therapy** after lumpectomy for DCIS to reduce the risk of local recurrence. It is not a standalone primary treatment for removing the initial non-invasive malignancy.
- The first step is always surgical removal of the cancerous tissue.
*Bilateral mastectomy*
- **Bilateral mastectomy** is a more aggressive surgical intervention, typically reserved for **invasive breast cancer**, widespread DCIS, or cases with very high genetic risk (e.g., BRCA mutations).
- For localized non-invasive malignancy identified through microcalcifications, a lumpectomy is generally the **most appropriate and less invasive initial surgical approach**.
Sentinel lymph node biopsy US Medical PG Question 10: A 58-year-old woman underwent mastectomy for multicentric DCIS. Final pathology shows high-grade DCIS with comedonecrosis, margins negative by 3 mm, no invasion identified in 40 tissue blocks examined. Sentinel lymph node biopsy shows isolated tumor cells (0.1 mm cluster) positive for cytokeratin. The medical oncologist requests input on systemic therapy. Evaluate the significance of the nodal finding and recommendations.
- A. Upstage to invasive cancer, recommend chemotherapy and endocrine therapy
- B. Perform completion axillary dissection to assess additional nodal involvement
- C. Consider isolated tumor cells clinically insignificant, node-negative staging, endocrine therapy only if ER-positive (Correct Answer)
- D. Recommend axillary radiation and systemic chemotherapy
- E. Repeat pathology review to identify occult invasion
Sentinel lymph node biopsy Explanation: ***Consider isolated tumor cells clinically insignificant, node-negative staging, endocrine therapy only if ER-positive***
- Per AJCC guidelines, **isolated tumor cells (ITCs)** (clusters ≤ 0.2 mm or < 200 cells) are staged as **pN0(i+)**, which is considered node-negative disease.
- In the setting of pure **DCIS**, ITCs do not warrant staging as invasive cancer nor do they justify **systemic chemotherapy**; management depends solely on the tumor's **ER-status** for endocrine therapy.
*Upstage to invasive cancer, recommend chemotherapy and endocrine therapy*
- Staging cannot be upgraded to invasive cancer unless a **pathological focus of invasion** is identified in the breast tissue (T category).
- **Chemotherapy** is never indicated for pure DCIS, regardless of high-grade features or the presence of ITCs in the lymph nodes.
*Perform completion axillary dissection to assess additional nodal involvement*
- **Completion axillary lymph node dissection (ALND)** is not indicated for ITCs, as they do not carry the same prognostic weight as macro-metastases.
- In pure DCIS, the presence of ITCs is often attributed to **mechanical transport** of cells during biopsy rather than true metastatic potential.
*Recommend axillary radiation and systemic chemotherapy*
- **Axillary radiation** is reserved for patients with significant nodal burden and is inappropriate for **pN0(i+)** status.
- Because DCIS is a non-invasive, **pre-cancerous lesion** contained within the basement membrane, systemic chemotherapy provides no benefit and unnecessary toxicity.
*Repeat pathology review to identify occult invasion*
- While high-grade DCIS increases the risk of occult invasion, the examination of **40 tissue blocks** is considered exhaustive and standard for ruling out invasion.
- Persistent searching for micro-invasion after comprehensive sampling is unlikely to change the clinical management dictated by the **pN0(i+)** finding.
More Sentinel lymph node biopsy US Medical PG questions available in the OnCourse app. Practice MCQs, flashcards, and get detailed explanations.
