Women Develop BRCA-Related Cancer Earlier Than Their Moms, Study Says More research is needed to link cause to environment or better testing.

Sept. 12, 2011  -- Jessica Denton was 34 years old and pregnant with her first child when she found a lump in her breast. She said her doctor said that it was nothing, that everything grows during pregnancy.

After the lump increased in size and became abnormally shaped, she again had it checked out.

"I ignored it for about five months," she told ABC News. "It grew so fast and it just didn't feel right. I went to my [obstetrician]. ... That's when we got the diagnosis."

Denton, who had not yet had her first baseline mammogram in 2008 when she first found the lump, was diagnosed with breast cancer and tested positive for the BRCA-2 gene. After her diagnosis, she found out that she had inherited the gene from her great-aunt on her father's side.

Her Aunt Pearl had gotten breast cancer in her late 60s or 70s and had tested positive for the BRCA gene. Though her aunt had informed Denton's parents 12 years ago that she was BRCA positive, Denton said they did not share the information with her.

"It just didn't send up any red flags in them," she said. "And it should have."

Breast Cancer Develops Earlier

Denton's belief is backed up by a study by researchers at the University of Texas MD Anderson Cancer Center in Houston published online today in the journal Cancer, which found that women with cancer related to the BRCA gene developed the disease years younger than their relatives in the previous generation.

"Specifically in women with BRCA-1 or -2 mutations, we were looking to see if the daughters were getting the disease earlier than their moms or aunts," said Dr. Jennifer Litton, a breast medical oncologist at the University of Texas MD Anderson Cancer Center in Houston, whose team conducted the study.

Of the 132 women in the study who had breast cancer and BRCA gene mutations, 106 had a family member in the previous generation who had been diagnosed with either BRCA-related breast or ovarian cancer. Researchers also found that the average age of cancer diagnosis went from 48 in the older relative to 42 in the younger generation.

"I think this validates a lot of the guidelines out there for us to start looking at least five to 10 years earlier than the youngest diagnosis in their family," Litton said.

In Denton's last trimester, she underwent chemotherapy. After her daughter was born, the new mother underwent a double mastectomy, aggressive chemotherapy and radiation.

"We went through the treatment, step by step, and it was not easy and it's not fun, but we made it through and I feel very lucky," said Denton, who is now cancer-free and pregnant with twins.

"[Doctors] suspected that it could have been the BRCA only because I'm so young," she said. "I certainly would have gotten mammograms earlier. I would never have had a mammogram (because of her young age) but I would have done it had I known I had the gene."

Researchers at the University of Texas said the findings also gave weight to so-called "anticipation" in breast and ovarian cancer, in which later generations had earlier onset and more severe disease than their ancestors.

It's still unclear why the younger generation develops cancer earlier. For now, Litton said she wanted to see the study done with larger groups of women to determine whether the reason is environmental or due to better testing.

It is recommended that women with the gene mutation start breast cancer screening at the age of 25.

"For women with a known BRCA-1 and -2 mutation, we do know that women get cancers earlier than the rest of the population," she said. "Doing appropriate screenings, starting the screening on time can find cancers at earlier stages."

MedPage Today contributed to this article.