WASHINGTON Women who survive breast cancer for five years after treatment have a relatively low risk of the disease recurring, according to a U.S. study published on Tuesday.
Even women with serious stage III breast cancer have only a 13 percent risk of the cancer returning if they survived the first five years cancer free, researchers said, commenting on a study that generally did not include some newer treatments such as Herceptin and the aromatase inhibitors.
The researchers tracked breast cancer recurrence in 2,838 U.S. women who had been cancer-free for five years after initial surgery and radiation to remove the tumor, followed by chemotherapy, hormone therapy, or both.
In those treated for stage I breast cancer -- the tumor was small and had not spread -- breast cancer came back after five years in just 7 percent.
The cancer returned in 11 percent of women treated for stage II disease -- the tumor may have been a bit larger or spread to the lymph nodes under the arm.
And 13 percent of women treated for stage III disease -- the tumor may have been larger, may have spread to additional lymph nodes or may have grown into the chest wall or skin of the breast -- saw a recurrence after five years.
"A very common question that women who are five-year breast cancer survivors ask us as oncologists is, 'What is my risk of recurrence of breast cancer now?' And that's a number that we've had a hard time coming up with," Dr. Abenaa Brewster of the University of Texas M.D. Anderson Cancer Center in Houston, who led the study, said in a telephone interview.
"I actually think that patients think that the risk is a lot higher than it is. So I hope that this paper somewhat reassures them that their risk of recurrence after they are five-year survivors is probably not as high as they think it is," Brewster added.
The women in the study, published in the Journal of the National Cancer Institute, were treated at M.D. Anderson between 1985 and 2001.
The study did not assess the effect on recurrence risk of some of the more recent additions to breast cancer treatment, including the class of drugs called aromatase inhibitors and the Genentech Inc cancer drug Herceptin.
The study found that women who had tumors known as estrogen receptor positive, in which the hormone estrogen is driving the tumor, had a higher risk of these late recurrences compared to women whose tumors were not this type.
Women who had low-grade, or less aggressive, tumors, actually had a higher risk of late recurrence than women who had higher grade tumors, Brewster said. "That was certainly a finding that we were surprised to see," she said.
Breast cancer is the top cause of cancer death among women worldwide, with an estimated 465,000 deaths annually, according to the American Cancer Society.