Does pregnancy-associated breast cancer influence survival?

In this study, researchers examined whether pregnancy-associated breast cancer (PABC) was linked to more advanced breast cancer or whether this influences survival compared to non-PABC.

PABC is defined as breast cancer diagnosed during pregnancy or within 2 years of giving birth. Some studies suggest that PABC patients have lower survival than non-PABC patients (patients whose breast cancer was diagnosed before pregnancy or more than 2 years after pregnancy). Because women’s breasts undergo hormonal and tissue changes during and after pregnancy, it has been suggested that these changes lead to more aggressive breast cancer. It has also been suggested that pregnancy and birth make detection of cancers more difficult, which could cause breast cancer to evade detection before it reaches an advanced stage. Whether PABC patients do have more advanced or aggressive cancers, this could explain why they have poorer survival. In order to accurately diagnose and treat PABC, there is need for a better understanding of the reasons why survival might be poorer for these patients than in non-PABC patients.

Researchers evaluated 3,282 breast cancer patients between 15-44 years old for differences between breast cancer stages and survival. 9% (937) of these women had PABC. Women diagnosed with PABC within 1 year of giving birth were more likely to have advanced tumors. Overall, PABC patients tended to have larger, more advanced tumors. This tendency toward more advanced tumors persisted until 5 years after giving birth. Regarding patients’ age, however, researchers found that only older PABC patients (35-44 years old) had more advanced tumors. Younger PABC patients (15-35 years old) did not have more advanced tumors compared to non-PABC patients of the same age. The effect of patient age extended to survival of these patients, as well. Although PABC patients had a 47% poorer survival than non-PABC patients overall, when researchers considered the patients’ age, there was only an 18% lower survival for PABC patients compared to non-PABC patients of a similar age, which was not statistically significant.

In summary, older PABC patients (35-44 years old) were more likely to have more advanced tumors. However, when compared to non-PABC patients of the same age, there was no consistent effect of PABC on survival.

This study was conducted over a relatively short time period (8 years) and because PABC is rare, there were few patients with PABC available for analysis. However, this is one of the largest studies on PABC ever conducted.

Talk to your doctor about the prognosis for PABC and the most appropriate treatment options in your situation.