Well, about the early detection, yes, it is completely curable in the early stages. One of my relatives had breast cancer and she is completely cured now, and is not on any medication currently. But the problem is that it's difficult to rule out at the early stages. For some people the disease is more symptomatic, while in most of the cases, it is asymptomatic. That's why it is called the 'Silent killer'. As you are having family history of cancer, you need frequent, say at least once in three or four months, medical checkup and ensure that you are unscathed.
Anyway it doesn't solely depend on the genetic factors, but as you are already in a risk of developing cancer, I advice you to modify your lifestyle by a great extent, by avoiding carcinogenic substances, and having good exercise to keep yourselves fit. Above all keep grinning out there

All the best!