ATLANTA — Young women who became pregnant after breast cancer treatment were significantly less likely to have a recurrence or to die of the disease, according to a French retrospective study presented at the annual meeting of the American Society of Clinical Oncology.
Dr. Rémy Largillier reported that 5-year overall survival was 97% for 118 women who became pregnant after breast cancer, but only 80% for 762 women who did not. The hazard ratio in favor of pregnancy was 0.23.
“Perhaps it is not a [contraindication] to have a pregnancy,” Dr. Largillier, of the Centre Antoine Lacassagne in Nice, and his coinvestigators concluded.
In a discussion of the poster, Dr. Robert W. Carlson, professor of medicine at the cancer center of Stanford (Calif.) University, described the study as important, but cautioned that it was not cause to encourage breast cancer survivors to become pregnant. The positive outcome “may be nothing but a healthy mother effect,” he said.
The take-home message, Dr. Carlson said, is that “pregnancy subsequent to breast cancer does not have a negative impact on breast cancer outcome, and a pregnancy recent to a diagnosis of breast cancer does not independently predict for a poor outcome.”
In conducting the study, the investigators cited the lack of data supporting the decision of many women to wait at least 2 years after breast cancer treatment before they become pregnant. Although some studies have suggested that pregnancy might be protective, Dr. Largillier's group acknowledged that these studies may have been biased by the “healthy mother” effect, in which only women who feel healthy and disease-free choose to become pregnant.
The study reviewed 908 patients younger than age 35 years who were treated for nonmetastatic and unilateral invasive breast carcinoma at eight French hospitals between 1990 and 1999. The women's average age was 31.4 years, and the median follow-up was 87 months.
Included in the analysis were 105 women who gave birth during the year prior to their diagnosis. The investigators found that these women were significantly more likely to have a positive axillary node (49% vs. 36% of those who did not give birth before diagnosis), a tumor staged as T2 or greater (75% vs. 56%), and a cancer classified as estrogen-receptor negative (54% vs. 43%).
Pregnancy in the year before diagnosis increased the risk of death and risk of local recurrence in univariate analysis. Only the relationship to local recurrence persisted in multivariate analysis, however. The hazard ratio was 1.75.
Women who became pregnant after treatment were significantly younger than the rest of the population and less likely to have a family history of breast cancer. More than half (53%) were younger than 30 years of age, compared with 28% of those who did not become pregnant as breast cancer survivors.
The posttreatment mothers also were more likely to have positive axillary nodes (38% vs. 29% of women who did not become pregnant after diagnosis), but their tumor size and estrogen-receptor status were similar to the rest of the population.
Women with good prognoses after completing breast cancer treatment had a low annual risk of distant recurrence that remained constant over time, according to the investigators. This was not the case for the women with poor prognoses: They had a high annual risk of distant recurrence that did not level off for 80 months. After that point, their risk was no greater than the risk for the women with good prognoses.
“In this large study population, pregnancy was not associated with poorer survival,” the investigators concluded, but they advised that for women with poor prognoses after breast cancer treatment, “it is very important to wait 5 years before a pregnancy.”
For women with a poor prognosis after breast cancer, 'it is very important to wait 5 years before a pregnancy.' DR. LARGILLIER