Rows or columns?

#1
In a clinical statistics workshop we were given this question? Can anyone help me, I've been tearing my hair about it:

A case control study of risk factors for testicle cancer identified heavy smoking, as one of the major risk factors.

Results:

------------Heavy_smoker
-----------|No | Yes |-------Total
Cancer---+----------------------+-
No-------|650 | 105 |-------755
Yes------|100 | 90 |---------190
-----------+----------------------+----------
Total-----|750| 195 |--------945

Row and column probabilities can be calculated for table above, but only one of these alternatives is meaningful. Which and why?
 

Karabiner

TS Contributor
#2
I suppose that you should decide what is more meaningful,
either to know a) how many % of smokers got cancer compared
with non-smokers, or b) to know the proportion of smokers in
cancer patients versus proportion of smokers in other subjects.
i.e., is cancer supposed a risk factor for smoking, or is smoking
a risk factor for cancer?

HTH

P.