Core Framework & Diagram Why Does Cancer Metastasize?

Yes, still possible. 'Surgery cut clean' means no residual tumor visible to the naked eye and imaging, but this doesn't rule out micrometastasis that may have occurred before surgery. A small number of cancer cells may have already left the primary tumor before surgery, entering blood or lymph circulation and 'sleeping' in distant organs. This is why high-risk patients after surgery usually need adjuvant chemotherapy, radiation, or immunotherapy — precisely to eliminate these possibly existing micrometastatic lesions.

In some situations, yes. Traditionally, metastatic cancer was considered incurable. But today, several scenarios show 'cure' possibilities: immune checkpoint inhibitor treatment followed by durable complete remission (approximately ten to twenty percent of late-stage melanoma patients achieve ten-plus years of durable remission); isolated liver/lung metastasis surgical resection (like colorectal cancer with one to three liver metastases completely resected achieving thirty to forty percent five-year survival rates); complete remission after CAR-T for hematological malignancies.

Evidence supports this. Exercise theoretically can reduce metastasis risk through multiple mechanisms: improving NK cell activity, enhancing clearance of circulating tumor cells; lowering cortisol and adrenaline levels, reducing catecholamine's promotion of CTC survival and migration; improving insulin resistance, reducing high insulin/IGF-1's tumor-promoting growth effects. Multiple prospective studies found regular exercise correlates with improved metastasis-related survival indicators in breast cancer, colorectal cancer, and prostate cancer. Recommendation: at least 150 minutes of moderate-intensity aerobic exercise per week, combined with moderate resistance training.

There's indirect evidence. Vitamin D deficiency correlates with worse breast cancer patient prognosis (including bone metastasis risk); maintaining adequate vitamin D levels (serum 25-OH-D > 50 nmol/L) is a reasonable adjunct strategy. More evidence-supported bone protection strategies are: bisphosphonates (like zoledronic acid, which has strong evidence in post-menopausal breast cancer adjuvant treatment) and denosumab, both targeting osteoclasts and reducing bone metastasis-related event rates.