Association of molecular subtypes with local recurrence, distant metastasis and prognosis in breast cancer patients after modified radical mastectomy / 肿瘤研究与临床

ABSTRACT

Objective:To explore the association of molecular subtypes with local recurrence, distant metastasis and prognosis in breast cancer patients undergoing adjuvant therapy after modified radical mastectomy as well as its significance.Methods:The clinical data of 108 patients with breast cancer undergoing adjuvant therapy after modified radical operation in the First Affiliated Hospital of Xi'an Jiaotong University from March 2002 to March 2012 were retrospectively analyzed. According to the expressions of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor-2 (HER2), patients with breast cancer were divided into 4 molecular subtypes, including Luminal A, Luminal B, HER2-positive and triple-negative. The relationship between clinicopathological factors and molecular subtypes was analyzed, and the local recurrence rate and distant metastasis rate of breast cancer patients with various molecular subtypes were compared. Kaplan-Meier method and log-rank test were used to make single factor analysis of survival. Cox proportional hazard model was used to make multi-factor survival analysis.Results:Among 108 patients, 41 cases were Luminal A, 40 cases were Luminal B, 17 cases were HER2-positive and 10 cases were triple-negative. The differences in compositions of patients with age, tumor size, pathological type, lymph node metastasis, American Joint Committee on Cancer (AJCC) staging, vascular tumor thrombus, resection margin, and chemotherapy cycle number among groups with 4 molecular subtypes were not statistically significant (all P > 0.05), while the difference in compositions of patients receiving endocrine therapy was statistically significant ( P < 0.01). The local recurrence rate of patients with Luminal A, Luminal B, HER2 positive and triple-negative was 14.6% (6/41),15.0% (6/40), 11.8% (2/17), 10.0% (1/10), respectively, and the difference was not statistically significant ( P > 0.05). The distant metastasis rate of patients with HER2-positive and triple-negative was 35.3% (6/17) and 40% (4/10), respectively, which was higher than that of patients with Luminal A [24.4% (10/41)] and Luminal B [22.5% (9/40)], but there was no statistically significant difference among the four types ( P > 0.05). Kaplan-Meier analysis showed there was no statistical difference in progression-free survival of patients with Luminal A, Luminal B, HER2-positive and triple-negative ( P > 0.05), while there was a statistical difference in the overall survival (OS) ( P = 0.047), and the OS of triple-negative patients was the worst, meanwhile AJCC staging, lymph node metastasis and endocrine therapy were associated with the OS (all P < 0.05). Multi-factor Cox proportional hazard model analysis showed that lymph node metastasis ( OR = 4.481, 95% CI 1.377-14.580, P = 0.013) and endocrine therapy ( OR = 0.165, 95% CI 0.034-0.800, P = 0.025) were independent prognostic factors affecting OS. Conclusions:There is no statistically significant difference in local recurrence rate for breast cancer patients with different molecular types undergoing adjuvant therapy after modified radical mastectomy. Breast cancer patients with Luminal have better OS, while those with triple-negative have the worst OS. Molecular subtypes may have an important significance for the treatment choice and prognosis judgement of breast cancer.