Tubular, cribriform and mucinous carcinomas account for <10% of all breast cancer histology. They have excellent prognosis and aggressive treatment with chemotherapy is usually not warranted. Younger age at breast cancer diagnosis is often associated with a poorer prognosis in early breast cancers, however little is known about the natural history of favourable-histology breast cancers for younger women compared to their older counterparts. We aim to compare the prognosis of younger women less than 45 years of age with their older counterparts for early breast cancers with favourable histology.
Using the SEER dataset from 1988-2015, we identified 20 577 women diagnosed with early stage breast cancers of favourable histology i.e. tubular, cribriform, and mucinous carcinoma. We extracted the information on age of diagnosis, estrogen receptor (ER) status, progesterone receptor status (PR), HER2 status, ethnicity, cause of death, and survival months. The survival was compared between women < 45 years of age at diagnosis versus ≥ 45 years using log-rank test and cox-regression to give a univariate and multi-variate analysis.
Among 20577 women with early stage favourable-histology breast cancers, we identified 1308 (6.4%) tubular, 6486 (31.5%) cribriform, and 12 783 (62.1%) mucinous breast cancer. The median age of diagnosis is 42 and 64 years of age for the younger group of < 45 years of age and older group of ≥ 45 years of age respectively. 85% of the breast cancer in younger women were ER+ while 88% in the older age group were ER+. In a univariate analysis, the median breast cancer specific survival for early stage favourable histology breast cancer was 120 months for women < 45 years of age and 100 months for women ≥ 45 years of age (p < 0.001). In multi-variate analysis, accounting for tumour size, nodal status, stage, grade, hormone receptor status, HER2 receptor status, histologic type and year of diagnosis, younger age still predicts for a better outcome (p < 0.001).
Younger women diagnosed with early stage favourable-histology breast cancers have a better prognosis compared to older women. This will help in counselling on prognosis and management of younger patients.
Guek Eng Lee.
Has not received any funding.
All authors have declared no conflicts of interest.