Wound healing after trauma may predispose to lung cancer metastasis: review of potential mechanisms

Inflammatory oncotaxis, the phenomenon in which mechanically injured tissues are predisposed to cancer metastases, has been reported for a number of tumor types, but not previously for histologically proven lung cancer. We review clinical and experimental evidence and mechanisms that may underlie inflammatory oncotaxis, and provide illustrative examples of two patients with squamous cell carcinoma of the lung who developed distant, localized metastatic disease at sites of recent physical trauma. Trauma may predispose to metastasis through two distinct, but not mutually exclusive, mechanisms: (1) physical trauma induces tissue damage and local inflammation, creating a favorable environment that is permissive for seeding of metastatic cells from distant sites; and/or (2) micrometastatic foci are already present at the time of physical injury, and trauma initiates changes in the microenvironment that stimulate the proliferation of the metastatic cells. Further exploration of post-traumatic inflammatory oncotaxis may elucidate fundamental mechanisms of metastasis and could provide novel strategies to prevent cancer metastasis.