Treatment of Invasive Lobular Carcinoma Associated with Lobular Carcinoma in Situ (LCIS)
Invasive lobular carcinoma associated with LCIS should be treated according to the invasive component guidelines, with breast-conserving surgery (BCS) or mastectomy plus appropriate axillary staging, followed by adjuvant therapy based on risk stratification. 1
Surgical Management
Primary Treatment Options:
- Breast-Conserving Surgery (BCS) with sentinel lymph node biopsy (SLNB) or axillary lymph node dissection (ALND)
- Mastectomy with SLNB or ALND
The choice between BCS and mastectomy depends on:
- Tumor size (contraindicated for BCS if >3-4 cm in small breasts)
- Multicentricity (contraindicated for BCS)
- Ability to achieve negative margins
- Patient preference
Axillary Management:
- Sentinel Node Biopsy (SNB) for clinically node-negative disease
- Axillary Dissection for:
- Clinically positive nodes
- Large tumors (>3 cm)
- Multicentric disease
- Positive sentinel nodes
Important Surgical Considerations:
- LCIS at surgical margins does not require re-excision 2
- Focus on achieving clear margins for the invasive component
- Unlike pure LCIS, the presence of invasive disease requires complete surgical excision
Adjuvant Therapy
Radiation Therapy:
- Mandatory after BCS for the invasive component 1
- Reduces local recurrence by two-thirds
- Provides survival benefit
- Exception: Patients >70 years with ER-positive, node-negative, small tumors may consider tamoxifen instead of radiation
Systemic Therapy (based on risk stratification):
Endocrine Therapy:
- Tamoxifen for premenopausal women
- Tamoxifen or aromatase inhibitors for postmenopausal women
- Duration: 5-10 years
Chemotherapy considerations based on:
- Tumor size
- Nodal status
- Grade
- Hormone receptor status
- HER2 status
- Patient age and comorbidities
HER2-targeted therapy if HER2-positive
Risk Stratification for Treatment Decisions
Risk assessment should be based on 1:
- Age (<35 years increases risk)
- Tumor size (>2 cm increases risk)
- Histopathological grade
- Vascular invasion
- Lymph node involvement
- ER/PR status
- HER2 status
| Risk Category | Features | 10-year Recurrence Risk |
|---|---|---|
| Low | Node-negative, ≤2 cm, Grade 1, ER/PR+, HER2-, Age ≥35 | <10% |
| Intermediate | Node-negative with risk factors OR 1-3 nodes with ER/PR+ and HER2- | 10-50% |
| High | 1-3 nodes with ER/PR- OR HER2+ OR ≥4 nodes | >50% |
Special Considerations for the LCIS Component
- The LCIS component itself doesn't require additional specific treatment beyond what's needed for the invasive cancer 1
- LCIS at surgical margins doesn't increase local recurrence risk when treating the invasive component appropriately 2
- Tamoxifen or raloxifene may be considered for risk reduction of contralateral disease 1, 3
- Studies show tamoxifen reduces invasive breast cancer risk by approximately 46% in women with LCIS 1
Follow-up
- Regular clinical examinations
- Annual mammography
- Consider MRI for high-risk patients
- Monitor for symptoms of recurrence or new primary tumors
Pitfalls to Avoid
- Don't ignore the LCIS component as a risk factor for contralateral disease
- Don't perform re-excision solely for LCIS at margins when invasive margins are clear 2
- Don't omit radiation therapy after BCS except in select elderly patients
- Don't overlook the increased risk of local recurrence in younger patients (<50 years) with LCIS and invasive disease 4
- Don't neglect endocrine therapy which appears to modify local recurrence risk in patients with LCIS 4
Remember that while pure LCIS is often managed by observation alone, the presence of an invasive component requires complete oncologic treatment with appropriate surgical management and adjuvant therapy based on the characteristics of the invasive disease.