Nowadays cancer is considered as a systemic disease that involves a number of pathophysiological pathways includes inflammation. Despite the fact both innate and adaptive immune response contribute to diminish or even control tumor growth and dissemination, the presence of perioperative infections can alter both of them. Both tumor growth and progression are strongly related to the interaction between tumoral cells and non-tumoral stromal cells. However, whereas the direct influence of infection-related proinflammatory events has little impact on tumoral cells behaviour, it can affect stromal cells reponse, leading to uncontrolled proliferation, enhanced tissue adhesion of vascular dissemination.
In general, the presence of surgical infections is related with a worst oncological outcome irrespective of which type infection is considered. Both surgical site infections and severe-systemic infections are correlated with diminished survival and augmented local and systemic recurrence.
When considering breast or gastric cancer, the presence of any type of infection or even wound complication has been correlated with lower survival rates. Nontheless, in colorectal cancer, the presence of any type of surgical infectious complication is associated with worst overall and cancer-related survival. Moreover, in presence of anastomotic leaks, depending on the severity (specially if diffuse peritonitis occurs) the prognosis varies, being much more favorable when small anastomotic dehiscence is found.
Nevertheless, although data from observational data indicates that the relationship between infection and tumor progression could be strong, it is important to consider that most of them are retrospective, small, single-center studies. Therefore, large studied based upon results from multicentric registries should be carried out.
Finally, despite the fact the mechanisms underlying this relationship between surgical infections and cancer progression remain unclear, several phenomena such as NK cells function impairment as well as disbalance in local cytokine production and effects have also been pointed out. Thus, in addition to current recommendations for surgical site infection prevention and systemic infections management, immune response modulation could also be considered as a putative therapeutical target.