One thing I have to say in all this Paul is that you as far as I know you had an underlying issue - diabetes - which could very likely have effected the way you responded to treatment. With diabetes, as I am sure you well know there are kidney issues, blood toxicology issues, circulatory issues etc... Making your case in particular far more complicated. There is also likely a personal sensitivity to chemo that was probably very much enhanced by the diabetes. So you are the 1 in a million in a lot of ways, since your response to chemo was far from average. When dealing with cancer, aggressive is generally what you want. Your drs of course need to consider any underlying conditions - but they are usually in a difficult position of what is too little in terms treatment when dealing with what is normally a very aggressive cancer, to avoid just the scenario you have faced... Multiple recurrences etc...
One thing I have noticed here is that there is always a fail rate amongst members, this is for varying reasons, individual habits and diet, overall health and individual anatomy, and aggressiveness of the cancer, but one disturbing pattern is that people who's drs tried to minimize treatment for whatever reason, tend to have to face the demon more than once.

Hugs....