[Micrometastasis: biological entity and clinical impact?]

Area of Science:

• Oncology
• Pathology
• Surgical Oncology

Context:

• Micrometastases and sub-micrometastases are small cancer deposits detectable in lymph nodes, bone marrow, and blood via histopathology and immunohistochemistry.
• The presence and extent of these microscopic metastases have significant prognostic and therapeutic implications in cancer management.
• Accurate assessment requires evaluating the rate of non-sentinel lymph node involvement post-axillary lymph node dissection and correlating with survival data.

Purpose:

• To highlight the clinical significance of micrometastases and sub-micrometastases in cancer staging and patient management.
• To differentiate the rates of non-sentinel lymph node involvement based on the presence and size of metastases (micrometastases vs. macrometastases).
• To underscore the importance of detecting micrometastases for determining overall and disease-free survival and informing adjuvant therapy decisions.

Summary:

• Standard histopathological methods, often enhanced by immunohistochemistry, can detect micrometastases and sub-micrometastases in various tissues.
• The rate of non-sentinel lymph node involvement differs significantly between patients with micrometastases (7-8%) and macrometastases (30-50%).
• Micrometastasis detection is vital for predicting survival outcomes and guiding the need for radiotherapy and chemotherapy.

Impact:

• Micrometastases significantly influence patient prognosis and the selection of appropriate cancer therapies, including chemotherapy and radiotherapy.
• Understanding micrometastasis rates aids in risk stratification and personalized treatment planning.
• While micrometastases have a clear clinical impact, the necessity of complementary axillary lymph node dissection remains an area of ongoing discussion.