Pregnancy influences breast cancer stage at diagnosis in women 30 years of age and younger.

BACKGROUND: To evaluate the purported decreased survival of pregnancy-associated (PA) breast cancer, a previously described homogeneous cohort of women of childbearing age with primary operable cancer was studied. The current analysis was designed to (a) identify those patients among the cohort known to have PA cancer and (b) compare clinical factors, pathologic characteristics, stage at diagnosis, and survival statistics for PA and non-PA cancer subgroups.
METHODS: All patients < or =30 years of age who underwent definitive operation between 1950 and 1989 at the Memorial Sloan-Kettering Cancer Center (MSKCC) for primary operable (stages 0-IIIA) breast adenocarcinoma were analyzed.
RESULTS: Twenty-two of the 227 young women with primary operable breast cancer had PA cancer. Disease-related survival was decreased (p = 0.004) in these 22 women compared with the remaining 205 patients with non-PA cancer. PA cancer patients were found to have larger tumors (p < 0.005), and a greater proportion had advanced staged (IIB or IIIA) cancers (p < 0.02). Among patients diagnosed with early invasive cancers (stages I or IIA), no difference (p = NS) in survival was observed comparing PA and non-PA subgroups (73% vs. 74% 10-year survival). Patients with stage IIIA cancer had shorter disease-free and overall survival when associated with pregnancy (0% vs. 35% 10-year survival).
CONCLUSIONS: Women 30 years of age or younger with PA breast cancer have decreased survival compared with patients with non-PA cancer from the same cohort. Women with PA cancer have larger, more advanced cancers at the time of definitive surgery. Women with early staged PA cancers appear to have survival similar to that for women with early staged non-PA cancer.