saturn is the lord of 7th and 8th houses for cancer lagna.
while lordship of 7th, a kendra is good for sani, 8th house lordship is definitely difficult.
for cancer lagna natives, it is perhaps this which gives a deep partner, but difficult partnership.
now suppose, this saturn is in a difficult house, say 12th house.
7th lord going into 12th will give either a foreign stay with partnership or it may bring bondage/limitations. But 8th lord coming into 12th will constitute a vipareet rajayoga, which will give comforts too.
how will be the dasa of saturn for a cancer lagna native?
consider the lordship of saturn from moon and surya as well and then decide the result.
for eg. if for a cancer ascendant native moon happens to be in taurus/rishabha, then sani becomes a yoga karaka by being the 9th and 10th lord.
but, if from moon and sun also, saturn happens to be the lord of difficult houses, of course, by the first stated dictum, sani dasa will be difficult.
the positive is that,
sani, the disciplinarian is one of the best masters ever possible.
you conduct yourself with restraint and detachment, and saturn will give you only peace.