After Neoadjuvant Therapy, Imaging No Longer Provides a Clear Answer
The following summary comes the article by Dr. Cristina Ferrone and was published in the International Journal of Radiation Oncology, Biology, Physics. The full article can be found here.
Patients with a presumed diagnosis of pancreatic cancer are initially evaluated by radiological imaging (Pancreas protocol CT-scan). Imaging provides a great deal of information regarding the tumor including tumor size, involvement of nearby blood vessels and organs, and distant spread of disease. Patients with tumors that involve nearby blood vessels may not be a candidate for a surgery-first approach and have been shown to benefit from upfront chemotherapy followed by potential surgical resection (see October blog post, “Outcome of Patients with Borderline Resectable Pancreatic Cancer in the Contemporary Era of Neoadjuvant Chemotherapy” for more information on vessel involvement).
Given the improvements in chemotherapy a majority of patients with pancreatic cancer are now managed via a neoadjuvant-first approach even when diagnosed at a resectable stage, given that systemic disease dictates long term outcomes. With this change in practice, a majority of patients initially receive chemo/chemoradiation therapy followed by a repeat scan (re-staging scan), and a potential surgical resection. Recently, it has become evident that post-neoadjuvant CT scans might not provide accurate assessment of disease. At Massachusetts General Hospital in Boston, MA, researchers have theorized that preoperative chemoradiation may cause tumors to appear worse on CT scans than before therapy. With this in mind, this group sought to find patients who received neoadjuvant therapy and had unfavorable imaging after the neoadjuvant therapy, but did have a good performance status and a decrease in pancreatic cancer tumor markers (CA19-9). These patients were taken to the operating room for surgical exploration to evaluate the true extent of disease. Promisingly, 92% of the first 40 patients underwent R0 resection margins, meaning there was no tumor seen at the resection plane (see August blog post, “The Importance of Resection Margin Status in Pancreatic Surgery” for more information on resection margins). What was observed on the CT-scans of these patients was most likely dead tissue with scarring that was mimicking living tumor.
In conclusion, patients with good performance status and decreasing tumor markers after neoadjuvant therapy should be considered for surgical exploration, even if CT scans demonstrate persistent tumor.
A special thanks for this summary by Michael Wright, Department of Surgery, Johns Hopkins School of Medicine and to Dr. Ammar Javed for his support.