First of all, I wouldn't wish such a horrendous disease as cancer on anyone.
That said, though, what choice did the lady leave the Magistrates? She's lucky that she didn't bring anyone's life to a premature end by driving whilst double the limit.
The fact that she has been given only a year to live has nothing to do with the sentence which I believe is just. Were the Magistrates expected to allow her to carry on driving for her remaining time?
No one forced the lady to down so much wine as to end up with her committing a serious driving offence. She got what she deserved.