The number of new cases of thyroid cancer among women in the U.S. has increased over the past decade despite a decline among women in mortality rates for most cancers, according to a report released Wednesday by the North American Association of Central Cancer Registries, the National Cancer Institute, CDC and the American Cancer Society, Long Island Newsday reports (Ricks, Long Island Newsday, 9/7).

According to the report, titled “Annual Report to the Nation on the Status of Cancer,” overall cancer mortality rates among U.S. women declined by 0.8% from 1993 through 2003. The types of cancer that showed a decline in mortality rates among women include bladder, brain, breast, cervical, colon, kidney, leukemia, myeloma, nervous system, non-Hodgkin’s lymphoma, rectum and stomach. Meanwhile, the number of thyroid cancer cases among women increased 4.6% annually from 1993 through 2000 and 9.1% annually from 2000 through 2003, the AP/Washington Post reports (Schmid, AP/Washington Post, 9/6). Of the nearly 327,000 people living with thyroid cancer in the U.S., more than 250,000 are women, and women will account for about 22,600 of the more than 30,000 cases diagnosed this year, the report finds. Researchers are uncertain why thyroid cancer cases have increased, the Washington Times reports. Len Lichtenfeld, deputy chief medical officer for ACS, called the increase “a phenomenon that was just recently recognized” and said it could be linked to childhood radiation exposure from tonsil therapy (Howard Price, Washington Times, 9/7).

Breast Cancer Rates

The report also finds that the rate at which women were diagnosed with breast cancer decreased from 137.3 cases per 100,000 women in 2001 to 124.2 cases per 100,000 women in 2003, the Washington Post reports. Brenda Edwards of NCI, who led the team of researchers, said the decline could be because of an increase in mammography screenings, a stabilization in the number of women delaying childbirth and a significant decrease in the number of women using hormone replacement therapy after menopause. According to Edwards and other experts, breast cancer incidence began to fall after millions of women stopped using HRT because of a study saying the therapy increases the risk of breast cancer, the Post reports. Edwards also said that more data is needed to confirm whether the decline in breast cancer incidence is a trend but added that “the news for us is breast cancer incidence, which we’ve been seeing increase for so many years, that increase has stopped” (Stein, Washington Post, 9/7).

Reaction

“When there are changes in trends like those reported for breast cancer and thyroid cancer this year, researchers are alerted to look for the causes, often leading to advances in cancer prevention and early detection,” John Seffrin, chief executive officer for ACS, said (AP/Washington Post, 9/7). “I think we’re finally beginning to see a change - that [breast cancer cases are] leveling off - and we may even be seeing the start of a decline,” Edwards said, adding, “We have to be cautious. But I think it’s real.” According to the Post, cancer researchers are “eagerly awaiting” data for 2004, which is being compiled now, to assess whether the drop in 2003 continued or whether the numbers remained the same (Washington Post, 9/7).