I would like to agree and take reassurance. However, my observations tell me otherwise.
My father had gastrointestinal symptoms, and years of routine colonoscopies, by one particular gastroenterologist. He moved out of state, after retirement. He went to a different doctor, for his routine colonoscopy, and it was discovered he had stage 4 colon cancer. The first doctor did not inspect the whole length of the colon, and was missing my dad's growing tumor, right where the small intestine joins the large intestine. Guess he didn't need his gall bladder removed, after all.
My mother had years and years of knee pain, tests, and scans, including x-rays and MRI's. She even went to a specialist at a renown university hospital. Recently, she went to a new knee specialist, who opened a practice nearby. They found multiple bone spurs, one of which was two inches long! Now, how in the world do you miss that?
I've heard it said, out of the mouth of doctors, "We call it the practice of medicine, because we practice medicine".
Whether we like it, or not, doctors and the practice of medicine is not certain. At the core of health anxiety is, ultimately, the fear of uncertainty. If we can accept uncertainty, I believe we can overcome health anxiety.