Cancer Metastasis via the Lymphatic System: Stepwise Process

Lymphatic metastasis is a major cancer spread route:

1. Primary Tumor invades local tissue.
2. Lymphatic Intravasation: Cancer cells enter lymphatic capillaries.
3. Transport: Lymph flow carries cells to regional lymph nodes.
4. Nodal Colonization: Cells proliferate in nodes → palpable enlargement.
5. Further Dissemination: Via lymphatic channels to distant nodes or hematogenous spread from nodes.
6. Secondary Tumors: Metastases establish in new organs.

Clinical Significance

• Sentinel node biopsy stages nodal involvement.
• Nodal status guides adjuvant therapy and prognosis.
• Lymphatic spread patterns are tumor-type specific (e.g., breast → axilla; melanoma → regional basins).

Accurate staging requires imaging + pathological nodal assessment.