Surgery MCQs Q21

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SURGERY • BREAST

A 45-year-old woman undergoes a breast biopsy for a suspicious lesion, and histology reveals lobular carcinoma in situ (LCIS). She is otherwise asymptomatic and seeks counseling regarding her future risk of invasive breast cancer.

Which of the following statements is true?

A The most common invasive cancer after LCIS is lobular carcinoma

B Her risk of invasive carcinoma is equivalent in both breasts

C Her risk is significantly increased if a large focus of LCIS is present

D Her risk is highest within 10 years and then becomes minimal

E Early menarche and late menopause carry higher risk than LCIS

Bilateral Equal Risk. LCIS is a marker of increased risk rather than a direct localized precursor. The risk of future invasive carcinoma is roughly equal for both breasts, necessitating bilateral surveillance.

Decoding the Stem

1

CLUE "LCIS diagnosis → counseling on future invasive cancer risk"

TRANS LCIS = Marker of risk (bilateral increased risk), NOT a localized precursor.

Explanation

B. Risk is equivalent in both breasts: Correct. Unlike DCIS, which is a localized premalignant lesion, LCIS acts as a marker for a general increase in risk (~8-10x) across both breasts equally.

A. Most common invasive cancer: Incorrect. Even in women with LCIS, the most common subsequent invasive cancer is invasive ductal carcinoma (IDC), not lobular.

C. Large focus: Incorrect. The risk is generally not dependent on the size or multicentricity of the LCIS focus found on biopsy; its presence alone is the marker.

D. Time frame: Incorrect. The risk associated with LCIS is lifelong and persistent, requiring long-term vigilance.

E. Hormonal factors: Incorrect. While early menarche/late menopause are risk factors, LCIS carries a significantly higher relative risk for future invasive cancer development.

🧠 High-Yield Pearls

Feature	LCIS	DCIS
Nature	Risk Marker	Localized Precursor
Laterality	Bilateral Risk	Ipsilateral Risk
Invasive Type	Mostly Ductal (IDC)	Ipsilateral Ductal
Management	Surveillance/Tamoxifen	Surgery/Radiation

Integrated Clinical Questions

1. LCIS vs DCIS main difference?

Answer: LCIS = risk marker (bilateral), DCIS = premalignant localized lesion.

2. Most common invasive breast cancer overall?

Answer: Invasive ductal carcinoma.

3. Risk increase in LCIS compared to general population?

Answer: Approximately 8–10 fold increase.

4. Preventive drug option for LCIS patients?

Answer: Tamoxifen (Selective Estrogen Receptor Modulator).

5. Follow-up strategy for LCIS?

Answer: Regular bilateral mammography ± MRI, as both breasts are at risk.

⚡ Exam Pearls

• LCIS = both breasts at risk (Bilateral marker).
• Risk is persistent/lifelong, not time-limited.
• Most common invasive cancer after LCIS = Ductal.
• Management is usually surveillance or chemoprevention, rarely prophylactic surgery.

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