Hi CM -
I am a hepatobiliary and transplant surgeon, new to this blog, but excited to participate as it has been a great service to so many of my patients.
Cholangiocarcinoma is generally thought of as an "indolent" cancer - we believe that in most cases it takes months to years to grow such that it eventually causes symptoms or signs that lead to diagnosis. In fact, it is this behavior that leads to many patients being diagnosed at advanced stages, as the disease has had much time to grow and potentially spread prior to diagnosis.
Obviously in any one case it is impossible to answer, but I suspect your loved one had this disease evolving for at least months if not longer prior to his diagnosis.
In some circumstances I meet a patient who had imaging studies or laboratory studies that were performed months (in one case I recall 18 months) prior to diagnosis and in retrospect showed abnormalities that suggested the cancer was there, though unfortunately missed. We obviously need to get better at diagnosing this cancer earlier in its course.
Hope this answer is helpful.
University of Michigan