Parity Status Predicts Breast Cancer Prognosis Later in Life

NEW ORLEANS—Having a previous pregnancy improves the prognosis for women who develop early-stage breast cancer later in life, according to a study presented at the 44th Annual Meeting of the American Society for Therapeutic Radiology and Oncology (abstract 152). The findings suggest that a more aggressive treatment approach should be considered for those patients who have not had a pregnancy.

Among patients 60 years of age and older, the 10-year cause-specific survival rate was 76% in women with no prior pregnancy, compared with 92% in women who had been pregnant earlier in life.

"This is the first report to demonstrate significant difference in outcome for women older than 60 years of age," said lead investigator Penny R. Anderson, MD, a radiation oncologist at Fox Chase Cancer Center. "These results suggest that no prior pregnancy may be considered a prognostic factor and perhaps could be used for early identification of patients who are at higher risk of developing distant metastasis and worse outcome, and who might benefit from a more aggressive initial treatment approach."

The study included 1,358 women with stage I/II breast cancer who had undergone lumpectomy, axillary dissection, and radiation therapy with or without systemic therapy between 1979 and 1996—1,162 women with a prior pregnancy and 196 women who had never been pregnant. Prior pregnancy was defined as a full-term, live birth.

Overall, the median age was 56 years. Median age at the time of first pregnancy was 24 years. Median follow-up was 7 years. The median age of the women with a history of pregnancy was slightly higher (57 vs 52 for the women with no history of pregnancy). There were also differences in age distribution, with a slightly higher percentage of older women and a higher percentage of postmenopausal women in the group with a history of prior pregnancy.

Patients Older Than 60

This led the researchers to perform a multivariate analysis on outcome variables according to age older than 60. In this multivariate analysis, no history of prior pregnancy was an independent predictor of distant metastasis, cause-specific survival, and overall survival.

Patients older than 60 years who had never been pregnant were more likely to present with larger T2 tumors than those who had a prior pregnancy (38% vs 22%, P = .0035), Dr. Anderson reported.

Although there were no significant differences in terms of 10-year local and regional cancer recurrence rates in the patients over age 60, those with no previous pregnancies had a significantly higher rate of distant metastases at 10 years (18% vs 13%, P = .09) and a higher 10-year actuarial rate of overall distant metastases (22% vs 10%, P = .0047), compared with those with prior pregnancies.

In addition to higher 10-year cause-specific survival (92% vs 76%), women in this age group with a history of pregnancy had a higher 10-year overall survival rate (76% vs 50%, P = .0128).

In patients older than 60, pregnancy status was a positive predictor of outcome, Dr. Anderson concluded. Adverse predictors of outcome in this older patient group, she noted, were use of prior chemotherapy and physical examination as the sole method of detection.