Importance of Carbohydrate Antigen 19-9 Monitoring in the Management of Pancreatic Cancer

Pancreatic cancers are rich with tumor stroma, which at times can account for over 80% of the tumor mass. As a result, it is not uncommon that pancreatic cancers demonstrate little to no radiographic changes in response to therapy. Lack of reliable radiographic response remains a major challenge to assessing biologic response to therapy and confounds appropriate surgical selection. In addition, subjectivity and inter-reater variability complicate assessments of treatment response. Optimal assessment of treatment response would require an objective, quantitative measure which ideally would be easily accessed and reproducible. Herein we describe the use of a serum biomarker, carbohydrate antigen (CA) 19-9 in patients with pancreatic cancer. CA19-9 values have a wide dynamic range and response to therapy (particularly normalization of an elevated value) has important prognostic implications. Routine incorporation of CA19-9 monitoring in patients undergoing neoadjuvant therapy adds significant value and should be performed routinely in all patients.