The biology and treatment of oligometastatic cancer

Abstract

Clinical reports of limited and treatable cancer metastases, a disease state that exists in a transitional zone between localized and widespread systemic disease, were noted on occasion historically and are now termed oligometastasis. The ramification of a diagnosis of oligometastasis is a change in treatment paradigm, i.e. if the primary cancer site (if still present) is controlled, or resected, and the metastatic sites are ablated (surgically or with radiation), a prolonged disease-free interval, and perhaps even cure, may be achieved. Contemporary molecular diagnostics are edging closer to being able to determine where an individual metastatic deposit is within the continuum of malignancy. Preclinical models are on the outset of laying the groundwork for understanding the oligometastatic state. Meanwhile, in the clinic, patients are increasingly being designated as having oligometastatic disease and being treated owing to improved diagnostic imaging, novel treatment options with the potential to provide either direct or bridging therapy, and progressively broad definitions of oligometastasis.

Keywords: diaspora; metastasis; spectrum theory; therapy; tumor.

Figure 1. Oligometastatic disease versus systemic disease

(left) Oligometastatic disease. Metastatic growth potential is limited. This could be (a) secondary to due to environmental conditions in the primary tumor forestalling evolutionary clonal pressure, (b) cancer cells that slough out of the primary tumor that do not have the properties necessary to survive the circulation and invade into target organ sites, and/or (c) the cancer cells land in inhospitable target organs. (right) Systemic disease. Widespread metastatic growth potential is unlimited. This could be (a) secondary to due to environmental conditions in the primary tumor creating many undifferentiated, aggressive clones, (b) cancer cells that actively migrate out of the primary tumor that have the properties necessary to survive the circulation and invade into target organ sites, and/or (c) the cancer cells land in hospitable target organs.