The only trivial conclusion is that the treatement is more effective when the desease is caused by one condition vs. the other.
I disagree.
Condition Has X vs does not Has X is a prognostic factor for the treatment in question.
The table is 2 x 2 dichotomic: both the dependig variable (Has X/not Has X) and the outcome (No meta's/Meta's) only have 2 options.
From the figures alone, you cannot say that the current distribution is NOT by change, given the H0 hypothesis that bot conditions have an equal "effect" on the outcome.
B.t.w. "Has X" does not necessarly cause the disease. In stead of BRCA, I might have chosen ER+ or ER- receptor status of the tumor.
That one actually has been proven to be a prognostic factor for hormona,l treatment: if the tumor is ER+, there are significantly less patient with metastasis after hormonal treatment than in the group with ER- tumors.
You would get a similar table as in my example, and given thet correct statistical test, significance can be proven.
there isn't any between the two sets of clinical trials
I guess you misunderstand me.
There are no 2 separate trials.
There is 1 group of patients, they all get the same treatment and outcome (seems to) differ(s) between the two groups.
Identifying what is the factor that separates the two groups often is only discovered after treatment of the whole group (of course you must have considered it as a possibility and register that "property" of the inidvidual patient).
Bart