What is the pathophysiology of metastatic cancer?

• A. Tumour spread to bones, organs, or CNS causing pain and fracture risk.
• B. Localized tumor with no spread.
• C. Spontaneous regression.
• D. No systemic symptoms.

Answer: (D)

Metastasis happens when cancer cells gain the ability to spread beyond the original tumor and establish new tumors in distant sites. This involves a sequence: cells detach from the primary mass, invade surrounding tissue and the extracellular matrix, enter blood or lymphatic vessels, survive circulatory stresses and immune attack, exit vessels at a distant site, and proliferate in a new tissue environment. The “seed and soil” compatibility explains why certain cancers tend to colonize specific organs. Once metastatic cells have established themselves, disease becomes systemic because multiple organs may be involved, and the patient can experience effects from the overall tumor burden and organ dysfunction. That can include bone pain and fractures from bone metastases, jaundice from liver metastases, or neurological deficits from brain metastases, along with systemic symptoms like weight loss and fatigue. So metastatic cancer is characterized by spread to distant sites and resulting systemic involvement, not by a lack of systemic symptoms.