As @ItisIbeserk says, it's a mix of facts/data and personal opinion. I also wonder how complete this article is, and whether the Dr's book will actually place a little more emphasis on the fact that, "a correction needed to be made" (in more accurately diagnosing people) than is implied here.
I found her comments on cancer interesting and they mirror my own. But I think people's lack of awareness/understanding of the impact of cancer treatment reflects the wider public health failing around education.
It's also refreshing to hear a Dr admit that some clinical work has no effect on outcomes.
But, I think it's a little too simplistic to say people are being overdiagnosed with various conditions (not just cancer). That may very well be true, but it is one part of a bigger picture and a failed system. If people were better educated on cancer and all that goes with it, they'd be able to make more informed decisions. If Drs were taught communication skills as a core subject for every year of study, they'd be better able to communicate effectively with patients, also leading to more informed decisions. If schools were better funded and not made to teach to exam results, we'd no doubt have happier, healthier, more well-rounded children and it would be easier to cater to those with differing needs within the same classroom. If we changed the concept of work so that people could work 4 days a week as standard, more jobs were part-time/job share, salaries reflected the cost of living, people with disabilities were welcomed and adaptations made without a massive fight etc., then more people with health conditions would be able to both manage their conditions and remain employed.
I think more should be made of her very accurate and pertinent point that more people being diagnosed doesn't mean more people being helped.