In general, if recurrent cancer does not appear within five years of the initial diagnosis, the patient is often considered to be in long-term remission or potentially cured, depending on the cancer type. For pancreatic and other gastrointestinal cancers, CA 19-9 has been a standard biomarker used alongside surveillance imaging (such as CT or MRI) to monitor for recurrence.

Emerging technologies like circulating tumor DNA (ctDNA) analysis offer the potential for more sensitive and earlier detection of recurrence by identifying tumor-specific genetic material in the blood. However, while promising, ctDNA is not yet a standard of care, and its role in routine surveillance is still being determined through ongoing clinical trials and research.