68Ga-FAPI-46 in Staging of Pancreatic Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and deadly types of cancer. It often develops without clear symptoms and is usually diagnosed at a late stage, when treatment options are limited. Even when surgery is possible, the cancer often returns. Current imaging methods like contrast-enhanced CT (ceCT) and MRI are useful tools but have important limitations. They may not clearly show the edges of the tumor, may miss small areas where the cancer has spread, and can be unreliable after chemotherapy, when inflammation can interfere with image interpretation.

This study focuses on a new imaging method called 68Ga-FAPI-46 PET/CT. This technique uses a tracer that attaches to a protein called FAP (fibroblast activation protein), which is found in high amounts in the tissue that supports the growth and spread of pancreatic tumors. These supporting cells, called cancer-associated fibroblasts (CAFs), help the tumor grow, invade nearby tissue, and avoid the immune system. By targeting this protein, the technique can provide highly detailed images of the tumor and the area around it.

Unlike standard PET/CT scans that use sugar-based tracers (such as 18F-FDG), FAPI PET/CT does not rely on the tumor's sugar use to detect it. This is important because many pancreatic tumors do not show up well with FDG scans due to their low activity level. Instead, the FAPI scan focuses on the surrounding tissue that often reacts strongly to the presence of cancer, offering a more complete and accurate picture.

In this prospective study, 20 adult patients with confirmed pancreatic cancer scheduled for surgery will be recruited at Lausanne University Hospital (CHUV). Each participant will receive a single intravenous injection of the 68Ga-FAPI-46 tracer, with the amount based on their body weight. After about 60 minutes, a low-dose PET/CT scan will be performed, taking around 20 minutes. Patients will need to fast for a few hours and drink water before the scan, but no special contrast agents will be used.

After the scan, patients will receive a follow-up call within a few days to check for any side effects. Previous studies have shown that this scan is very well tolerated, with no major side effects reported. Participation in this study will not interfere with any of the patient's normal care or treatment decisions.

The main aim of the study is to compare the results of the FAPI PET/CT scan with those of traditional imaging (CT and MRI) to see which gives better information about the size, shape, and spread of the tumor. Tissue samples collected during surgery will be used to confirm whether what the scan showed matches what is found in real tissue. This will help researchers understand how accurate and useful the scan really is.

Secondary goals include checking whether this technique can show if the cancer has spread to nearby lymph nodes or other organs. It may also help identify areas around the tumor that are more likely to lead to future cancer spread. Knowing this can help in planning surgery and follow-up treatment more precisely.

The study also includes exploratory goals, such as examining the presence of FAP-positive fibroblasts in the removed tissue and how they relate to the PET's results. We hope this will help us learn more about how the cancer behaves and spreads, which could help improve care in the future.

This pilot study will run for about two years. If successful, the results could support the use of 68Ga-FAPI-46 PET/CT as a new standard imaging tool for pancreatic cancer. It may allow for earlier and more accurate diagnosis, better surgical planning, and more personalized treatment decisions. In the future, this imaging technique could also be used for other cancers that involve the same protein, helping more patients benefit from better imaging and care.