NEW YORK (Reuters Health) - A new look at real-world outcomes for women with early-stage breast cancer finds that breast-conserving surgery may offer survival odds that are as good, or even better, than breast removal.
"It was kind of an exciting and hopeful message that women don't have to go off to get a mastectomy to do better," said Dr. E. Shelley Hwang, the study's lead author from the Duke Cancer Institute in Durham, North Carolina.
Despite clinical trials showing lumpectomy to be as effective as mastectomy in treating early breast cancers, the number of women choosing mastectomy has recently been on the rise, Hwang and her colleagues write in the journal Cancer.
To try to understand why, and to see whether the results seen in trials held up in the general population, Hwang's team looked at survival rates for more than 100,000 California women who had lumpectomy or mastectomy for early-stage breast cancers.
"I think a lot of women were making that decision (for mastectomy) because they thought the lumpectomy was not enough," Hwang told Reuters Health.
"In that context, we wanted to know if lumpectomy works just as well as mastectomy in the modern era," she said.
For the new study, the researchers used data collected by the Cancer Prevention Institute of California on 112,154 women who were diagnosed with stage I or II breast cancer between 1990 and 2004.
The majority - 55 percent - of women had a lumpectomy with radiation, and the rest had a mastectomy without radiation. The researchers then tracked the women's health for an average of nine years to see how they fared.
Overall, 31,416 women died by the time the study ended in 2009, and 39 percent of those deaths were due to breast cancer.
But researchers found the women who had a lumpectomy with radiation were more likely to survive than women who had a mastectomy, regardless of age or cancer subtype.
The difference was most pronounced among women who were over 50 years old and diagnosed with the most common type of breast cancer - one that's fed by hormones like estrogen or progesterone. Those who chose lumpectomy had a 19 percent lower likelihood of dying from breast cancer than counterparts who got mastectomies.
Hormone-sensitive tumors are generally considered easier to treat because they respond to hormone-blocking drugs. And cancers that occur in pre-menopausal women are often more aggressive.
But the survival advantage with lumpectomy held up even when researchers accounted for age, tumor stage and type, race, economic status and other factors. Among women younger than 50 with hormone-sensitive cancers, for instance, those who had lumpectomy had a 7 percent lower chance of death than those who had mastectomy.
Hwang said the survival difference between recipients of lumpectomy and mastectomy might be partly explained by the fact that women who got a mastectomy tended to be in worse health to begin with.
Her team also looked at causes of death in the short term, three years after treatment, to gauge whether other serious health conditions like heart or respiratory disease might have influenced a woman's choice to go with mastectomy and might also have skewed survival rates.
With other diseases taken into account, the survival advantage for lumpectomy was much smaller but still held.
The study cannot prove that lumpectomy is the factor responsible for the apparent survival benefit. And the researchers did not have access to some specific details about the women's tumors, or whether some women carried gene mutations that could affect their susceptibility to cancer or influence their treatment choices.
In 2013, The American Cancer Society estimates that 232,340 U.S. women will be diagnosed with breast cancer, and 39,620 will die from it.
In the U.S. a lumpectomy can cost over $7,000 while a mastectomy can cost more than $10,000. According to the American Cancer Society (ACS) each surgery comes with risks, including pain, swelling and scar tissue. Radiation, which usually accompanies lumpectomy, also comes with side effects, including complications during breast reconstruction.
Aside from surgery, ACS says women may also choose to be treated with chemotherapy, targeted genetic treatments and hormone-blocking therapy.
Hwang also cautions that the survival differences are relative and the actual benefit associated with lumpectomy in this study is small for an individual woman.
"I wouldn't overstate these results, because the survival difference can come from other things," said Dr. Dawn Hershman, co-leader of the Breast Cancer Program at the Columbia University Medical Center in New York.
But Hershman, who was not involved with the new study, told Reuters Health that the findings are reassuring.
"Sometimes patients in practice can be very different than patients in randomized trials. It's reassuring that patients who get breast-conserving therapy do at least as well as those with mastectomy," she said, adding that not all women are candidates for a lumpectomy.
SOURCE: bit.ly/14pbzCY Cancer, online January 28, 2013.