NEW YORK, Jun 01 (Reuters Health) -- Women who become pregnant after being successfully treated for breast cancer do not appear to increase their risk of cancer recurrence or dying from breast cancer, according to a group of researchers in Seattle.
"These findings are reassuring news for younger women with good-prognosis breast cancer," Dr. Priscilla Velentgas of the University of Washington told Reuters Health. "We found no adverse effects (of pregnancy) at all on recurrence of breast cancer."
In an editorial, published with the team's report in the June 1st issue of Cancer, cancer experts note that about 25% of premenopausal women who are treated for breast cancer may still wish to bear children..
A major study published in 1994 suggested that hormonal changes during pregnancy may promote the growth of cancer cells that remain after treatment. To study this risk, Velentgas and her colleagues studied the progress of 53 women who became pregnant after breast cancer treatment, and 265 other premenopausal women treated for breast cancer, matched for stage of disease at diagnosis and recurrence-free survival time, who did not become pregnant.
The researchers found that the rate of deaths from breast cancer did not differ between the two groups during the follow-up period, which ranged from 2 to 15 years.
Though the women who became pregnant were no more likely than other breast cancer patients to have a recurrence of their cancer during the follow-up period, they did have a 70% higher rate of miscarriage than expected, with 24% of the pregnancies ending in miscarriage. This may be because treatment for breast cancer changes women's hormones and makes them less able to carry a pregnancy to term, or it may be that the same factors that cause women to develop breast cancer also cause miscarriages in those women, the team speculates.
In an editorial in the same issue of Cancer, Dr. Hervy Averette and colleagues from the Sylvester Comprehensive Cancer Center in Miami, Florida note that "the current study... is particularly timely because it comes at a time when American women are opting for later childbirth and the incidence of breast carcinoma continues to rise in all age groups."
SOURCE: Cancer 1999;85:2301-2305, 2424-2432.
