If you think that you are safe from breast cancer because no one in your family had it, you are wrong as a new study reconfirms just because breast cancer has not struck a family before does not mean family members are safe from the disease.

Researchers found that most cases of breast cancer occurred in those without a family history of the disease after tracking more than 6,000 women for up to six years.

With nearly 200,000 new cases of invasive breast cancer, breast cancer accounts for about a quarter of all cancers in women.

Researcher Dr. Lawrence Wickerham of the National Surgical Adjuvant Breast and Bowel Project, NSABP, Allegheny Center, in Pittsburgh, said, "I have newly-diagnosed breast cancer patients ask me all the time how they could have developed the disease since they did not have a family history."

Prior studies have shown that less than half of the doctors ask about a woman's history of whether she has given birth or when did her menstrual cycle begin as more than 70 per cent of primary care doctors ask women about their family histories.

The roles of various risk factors among 6,322 postmenopausal women who had participated in two large trials of osteoporosis medications were analyzed by Wickerham, along with lead researcher Angelina Sontag, of Eli Lilly and Company, and their colleagues.

It was found that apart from women who had a family history of breast cancer, there were other women also who were high on the risk.