This article about dense breasts and breast cancer risk explains the relationship.  In general, younger women have denser breasts than older women, but they have fewer cases of breast cancer.  So keep in mind that in this case denser would mean denser than other women of a similar age.  You are correct that a history of breast cysts do not increase breast cancer risk.  Both breast cysts and dense breasts can make it harder to detect cancerous tumors.

Breast cancer risk is a tricky thing.  Plenty of women with no risk get breast cancer, and many women at high risk never do.  So women should not panic if they have risk factors, and they shouldn't be complacent if they have few or no risk factors.  Every woman needs to be alert to changes in her body and see her doctor about any changes that last longer than a menstrual period.

Be

11/ 4/09 8:16pm

Thanks. So a woman can have cystic breasts that are not dense? I thought that fibrocystic breasts are generally denser, which would seem to mean that having them is a risk factor for cancer because having them means having denser breasts.

PJ Hamel

11/ 4/09 9:10pm

Hi - As I understand it, breasts identified by a doctor as being clinically dense, and fibrocystic change (fibrocystic breasts), are two different things. Fibrocystic breasts are when your breast tissue grows too much, for whatever reason. This causes your breasts to be denser (less fat, percentage-wise). "Dense breasts" are breasts that are just naturally very fibrous - with very little fat. Unlike fibrocystic change, the tissue doesn't keep over-growing; it's stable, but the relationship of tissue to fat is high. I could be out in left field here - but that's how I understand it. Hope this helps - PJH