Studies on the distant relapse-free survival after relapse of different subtypes of breast cancer

Abstract

Objective To investigate the distant relapse-free survival, as well as survival after relapse, among different subtypes of breast cancer. Methods Patients with operable primary invasive breast cancer diagnosed in Zhongshan City People's Hospital from Jan. 1998 to Dec. 2004 were recruited. Subtypes were defined as luminal A, luminal B, human epidermal growth factor receptor 2 (HER2) enriched, and triple negative (TN) according to the expression of Estrogen Receptor (ER), Progestogen Receptor (PR) and HER2 status. The time of the appearance of the first distant metastasis and death of patients were recorded. Results Two hundred and fifteen (55.1%) patients were luminal A, 43 (11.0%) were luminal B, 52 (13.3%) were HER2 enriched, and 80 (20.5%) were TN. The median follow-up time was 118 months. In the first three years after operation, 19 (8.8%) and 2 (4.7%) metastases occurred in patients with luminal A and luminal B type of breast cancer, respectively. Patients with HER2 (19.2%) and TN type (20.0%) of breast cancer had a significantly higher metastasis rate than those with luminal type of breast cancer (P < 0.05). There's no significant difference of metastasis rate among the four subgroups during 37 months to 72 months after operation. Patients with luminal types of breast cancer had a higher rate of metastasis than patients with other types of breast cancer in the period of 73 months to 108 months after operation (P < 0.05). Median durations of survival with distant metastasis were 28 months for luminal A, 22 for luminal B, 9 for HER2, and 6 for TN (P < 0.05), respectively. Conclusions The subtypes of breast cancer are associated with distinct patterns of metastatic spread with notable differences in survival after relapse. Patients with HER2 type or TN type of breast cancer develop metastasis earlier than patients with luminal type of breast cancer did. The duration of survival after metastasis is longer for patients with luminal type of breast cancer than patients with other types of breast cancer. However, for patients with luminal types of breast cancer, the chance of relapse always exist, even in a relatively long time after operation. Key words: Breast cancer; Subtypes; Metastasis