Southern Cross has a great report on medical tourism available on their website (find it here). It looks like a pretty thorough piece of work and has looked hard at the question of medical tourism. They find that although it is a talked-about subject, there isn't much demand, and there is limited scope to reduce treatment costs using medical tourism. That's not because you can't buy cheaper procedures, it's mainly because of the attitudes of the people who need the procedures - some justified, some less so.
In essence, the cheaper the procedure the further you will have to fly to have it, and the higher the perception of risk around that trip. Picture yourself trying to convince Granny to travel to India for her hip replacement.
It takes a person more comfortable with different cultures, with a contemporary outlook, and more comfortable with risk to undertake medical tourism.
There were also some gaps in the analysis. One was the 'tourism' component - the report didn't consider the attraction of the visit as an end in itself, although, with a focus on recuperating from serious surgery, perhaps the opportunity for 'touring' would be quite limited. It isn't the case with all procedures. My father has travelled to have dental work done - in Hungary rather than the UK. Although the saving was great, the opportunity to spend a couple of weeks in a country that he loves practising speaking Hungarian, was a big part of the attraction.
Another issue, quite sensibly outside the concern of Southern Cross, is that medical tourism is likely to be of more interest to the uninsured: because they bear the costs of cover directly. If faced with a choice of, say, a waiting list of 18 months, a procedure at home which costs $15,000, or a procedure in India which costs $5,000 they may well choose to spend the money, and travel, to enjoy both the saving and the faster access to treatment.