Pathologic findings in nonpalpable invasive breast cancer

Area of Science:

• Oncology
• Pathology
• Radiology

Background:

• Nonpalpable invasive breast cancer often has a favorable prognosis.
• Previous studies lacked detailed analysis of mammographically detected tumors by size.
• Histopathologic features of these tumors require further investigation based on size.

Purpose of the Study:

• To compare the histopathologic features of nonpalpable invasive breast cancers based on tumor size (≤1 cm vs. >1 cm).
• To analyze differences in tumor types, grades, and in situ components between size groups.
• To evaluate residual disease and lymph node metastasis rates in relation to tumor size.

Main Methods:

• Retrospective analysis of 77 nonpalpable invasive breast cancer cases.
• Categorization into two groups: ≤1 cm (Group A) and >1 cm (Group B).
• Review of biopsy and mastectomy specimens, including axillary lymph node dissections.

Main Results:

• No significant differences in carcinoma in situ frequency, subtypes, or location between groups.
• Group B (>1 cm) showed a higher rate of residual invasive carcinoma (31% vs. 13%) and lymph node metastases (31% vs. 16%), though not statistically significant.
• Residual carcinoma in situ was significantly more frequent in Group B (54% vs. 26%, p = .036).
• In Group B, 71% of cases with negative biopsy margins still had residual invasive carcinoma.

Conclusions:

• Nonpalpable invasive breast cancers primarily differ by size.
• Negative biopsy margins in larger nonpalpable tumors do not rule out residual invasive disease.
• Further evaluation is necessary for complete assessment of residual disease.