Based on my knowledge coming from clinical research and a pancreatic survivor that has listened to case presentations, I recall a scenario where there was increasing CA19-9 but nothing had come up on imaging for quite awhile. Eventually recurrence was found along the surgical bed. I do not recall if imaging was by CT or PET. NanoKnife/IRE was the method of choice. The procedure was done at an NCI Center of Excellence, so a multidisciplinary tumor board evaluated all the particulars of the case in deciding to chose this over SBRT and Proton Therapy. Histotripsy was not available at the time.

NanoKnife was likely decided to be the most appropriate if the area is near critical structures (e.g., bile ducts, major vessels) and surgical resection is not feasible, as it minimizes damage to adjacent critical tissues.

If there is clearly a solid tumor meeting minimum size requirements, Histotripsy is the least invasive method. Recoverynis fast and in blasting a tumor with sound waves, it appears to cause an Abscopal Effect whereby antigens (proteins) on the cell surface have greater exposure to surveillance cells of the immune system. Essentially the tumor is more easily recognizable as “foreign” and antigen-presenting, dendritic, and macrophage cells are activated that can then target any. Circulating tumor cells and micrometastatic sites. Histotripsy is increasing in use but it has unique requirements athwart may complicate its use in those that had prior Whipple surgery. Fibrotic and scar tissues as a result of surgery can interfere with the penetration of sound waves. For this reason, a radiotherapy might be the next more likely treatment procedure.

SBRT is a strong alternative for patients who are not candidates for invasive procedures or when the lesion is amenable to radiation.

Proton Therapy and Histotripsy are less commonly used in this specific scenario. Familiarity is using proton therapy in this situation I am less familiar with. I do know that of the radiotherapy methods, proton beam therapy is the most precise with a pencil point targeting ability, thus reducing collateral Damage to surrounding tissue.