Rationale for systemic therapy administration in clinically localised tumors

Despite surgical excision remains the mainstay of cure for solid tumors, local, regional and systemic relapses observed in practice make clear that local treatment only is not enough. By the time of primary diagnosis of tumor the dissemination of cancer cells throughout the body had already started long ago. So the purpose of neoadjuvant systemic therapy is to eradicate micrometastases in order to diminish the risk of postpone the appearance of clinically detectable metastases which shoul result in improvement of relapse-free and overall survival of patients. However the biology of dissemination, persistence and proliferation of tumor cells at distant sites is poorly studied because these processes occure invisibly for modern clinical evaluation techniques and our understanding is based only on conclusions made indirectly from statistical and experimental data. Macroscopic metastases appearance depends not only upon tumor cell dissemination but also on the microenvironment at metastatic sites. As so, probably treatments specifically targeting microenvironment and metastatic tumor niche will have potential to improve the curability of localized cancer.