Bennett says there is "no firm prognosis" at this time.
Bennett also says he will enter treatment at Johns Hopkins University on Friday.
The full text of his Facebook post:
There have been a number of inquiries about my health from friends and former associates, expressing a solicitude for me that is very heartwarming. In response, I can now confirm that I have pancreatic cancer. At this stage, there is no firm prognosis.
I will be entering a treatment regime at Johns Hopkins University, with my first appointment set for Friday. The doctors are hopeful that a combination of chemotherapy and radiation can shrink the tumor to a point where it will become operable. As important milestones are reached, I will post further reports. All of us in the family express our deep gratitude for all of the expressions of comfort that we have received.