Positive sentinel lymph node biopsy on promotion of metastasis: An unexpected effect?

• The tumor-positive Sentinel lymph node biopsy (SLNB) risks promoting cancer metastasis. • SLNB may have activated dormant tumor foci or may have unintentionally provided more “seeds” or “soil.” • Animal studies are warranted to evaluate the metastatic effects of resectioning tumor-positive SLNs. • The strong correlation between positive SLNB and consequent metastasis is unexpected but can be fatal. The paradigm of most metastases has been interpreted as an orderly pattern of spread from the primary tumor to sentinel lymph nodes (SLNs). SLN biopsy (SLNB) has long been considered the standard of care for staging malignancy and guiding treatment. However, the process of SLNB may have awakened or inadvertently provided more “seeds” and/or “soil” to the early anchored tumor foci in regional or distant sites from the “disturbed” SLNs. Furthermore, tumor-positive SLNs are excised, and the angiogenesis inhibition of the distant metastasis dormancy foci is attenuated by the cessation of anti-angiogenic extracellular matrix proteins released from the tumor foci in the SLNs. Here, we hypothesize that tumor-positive SLNB risks the promotion of metastasis. The strong correlation between positive SLNB and consequent metastasis is unexpected but can be fatal. Therefore, verifying the phenomenon and exploring the mechanisms involved is essential to allow steps to be taken to offset this highly potential iatrogenic complication.