Analysis Of The Relationship Between Molecular Subtypes And Axillary Lymphatic Metastasis And Survival Of Breast Cancer Patients In T1 And T2 Stages

Breast cancer is one of the most common cancers occurring in women. The morbidity of breast cancer in north America and north Europe ranks first in the world. Although China is not a place with high breast cancer occurrence rate, the growth rate of breast cancer in China is 1-2% higher than that in other countries with high morbidity, thus, being the country with the highest morbidity increasing rate. Breast cancer is highly characteristic of heterogeneity, varying significantly from one individual to another in terms of clinical pathological tissue and immuno-phenotype. The response to treatment and prognosis of different subtypes are different. Histological type of breast cancer in early stage is useful for doctors to judge the recrudesce and transfer of this tumor, to offer guidance for surgery method and cutting range and determine the prognosis of patients. This research has retrospectively analyzed 2100 breast cancer cases diagnosed as invasive breast cancer and received cancer surgery in First Hospital of Jilin University from 2005 to 2013. In this study,four molecular subtypes, e.g, Luminal A subtype, Luminal B subtype, Her-2 over-expression subtype and Triple-negative subtype, have been compared regarding about their axillary lymphatic metastasis rate, factors affecting axillary lymphatic metastasis, DFS and OS,thereby, the influences of molecular subtypes on prognosis of breast cancer patients have been evaluated.Purposes: To explore the relationship between molecular subtypes and axillary lymphatic metastasis of breast cancer patients in T1 and T2 stages and make survival analysis.Methods: Retrospective analysis involving 2100 patients diagnosed as invasive breast cancer and received surgery in First Hospital of Jilin University from 2005 to 2013 has been conducted, to compare the four molecular subtypes, e.g, Luminal A subtype, Luminal B subtype, Her-2 over-expression subtype and Triple-negative subtype, regarding about their axillary lymphatic metastasis rate, factors affecting axillary lymphatic metastasis, DFS and OS. SPSS software(version 17.0)has been employed to implement computation and analysis.It is regraded that statistical result of p<0.05 as statistical significantly different. Chi-square test has been used to analyze the inter-group difference(Fisher test is used if necessary).Kaplan-Meier method is appleid to plot survival curve, and Log-rank test to compare the difference between survival rate. COX model has been used compute the single factor and multi-factors that possibly affect prognosis of breast cancer patients with the confidence interval of 95%.Results: In group T1 and T2, there is difference between varied molecular subtypes in terms of axillary lymphatic metastasis rate(p<0.05). Luminal B subtype has showed higher metastasis rate in both two groups, 31.15% and 37.48% respectively. However,Triple-negative subtype has showed lower rate in two groups, 12.50% and 16.44%respectively. In analysis of multi-factors affecting axillary lymphatic metastasis, Her-2over-expression is the independent risk factor of axillary lymphatic metastasis. There is statistical difference between patients of different molecular subtypes with respect to OS and DFS. Patients of luminal A subtype has manifested the highest five-year DFS rate(90.8%)and OS rate(93.5%), while patients of Triple-negative subtypes, the lowest rates(DFS rate:70.5%, OS rate:73.0%:DFS: Log-rank test2? =93.934,p=0.000; OS: Log-rank test2? =135.396, p=0.000). Among patients of Luminal B subtype, these whose ER and PR are positive have showed a higher DFS time and total time than others.(DFS: Log-rank test2? =8.577, p=0.003; OS: Log-rank test2? =7.622, p=0.006). Among the patients having received endocrine therapy, these whose ER and PR are positive showed longer DFS and OS than others(DFS: Log-rank test2? =11.012, p=0.001; OS: Log-rank test2? =5.433,p=0.020).Conclusions:(1) Luminal B subtype patients has a higher possibility of axillary lymphatic metastasis.However, compared with Her-2 subtype and Triple-negative subtype, Luminal B subtype has showed better prognosis than Her-2 subtype and Triple-negative.(2) Triple-negative subtypehas a higher possibility of axillary lymphatic metastasis,but it showed worst prognosis.(3) Her-2 over-expression is the independent risk factor affecting axillary lymphatic metastasis.(4) ER, PR double-positive patients compared with non-double-positive patients have a better prognosis.