Antitumor Immunity as Determining Factor for Prevention of Post-Surgery Cancer Recurrence

Cancer surgery is the oldest modality in cancer management and remains an effective cancer treatment that excises visible tumor and can result in long-lasting clinical cure. Yet the mechanism for the ability of surgery to cure cancer is not understood. The conventional thinking is that surgery effectively excises all tumor before it spreads and that results in cure. However, with more recent studies to detect circulating tumor cells that can still persist after tumor excision, it is now increasingly clear that early tumor spread before clinical detection is a common process of cancer development. Then the important paradoxical question is how does a local therapy such as surgical excision cure a systemic disease like cancer? We hypothesize that the interaction between tumor metastasis and antitumor immunity answers this question. The model, which we call “post-surgery tumor recurrence window model”, suggests that establishment of cancer metastases has an L –shaped kinetics following removal of the primary tumor. Similarly, pre-surgery concomitant antitumor immunity will also decay following surgery due to lack of antigen stimulation. Whether a new metastasis can establish is determined by the balance between these two processes. Here we present animal study evidence to support this model. We also present examples of how this model may be applied to predict post-surgery prognosis in individual cancer patients.