A postcode lottery?

All too often, the press highlights cases where cancers are not diagnosed at all, incorrectly diagnosed or diagnosed too late to be treatable. We hear of those who are labelled "hysterical" or "attention seeking" when they make numerous trips to their GP with symptoms whose causes aren't immediately obvious or that could be attributed to a number of different causes. We also read about "postcode lotteries", where someone living in one area gets better (or different) treatment from someone living in another area. 
I was pondering on my own experience (not good in some ways but excellent in others) and wondering how much evidence there is to support the claims that are made, when I heard of two people I know, living in different areas who have been treated completely differently since they discovered they had a recurrence.

One has received wonderful treatment, being followed up, reassured and given a huge amount of support. The other has been misdiagnosed and, despite having daily, medically trained carers visiting, the reason for their decline over the last few weeks has been attributed to cancer. It was only when they were admitted to hospital as an emergency this week that anyone noticed they had pneumonia and a twisted gut.  Now, we all know that mistakes can happen, but there do seem to be an awful lot of them around, and it's not reassuring to those of us who had to fight for a diagnosis in the first place!