Fertility Factors And Tumor Characteristics Among Young Breast Cancer Patients

Objective To analyze the associations between fertility factors with tumor characteristics and molecular subtypes among young breast cancer patients.Methods This study included a total of 1,587 young female patients(?40 years old)with no history of any previous cancer who were diagnosed with histologically confirmed breast cancer from January 2002 to January 2016 in the Affiliated Union Hospital of Fujian Medical University,and for whom the determination of the tumor ER,PR,and HER2 status and the patient reproductive data were all available.Tumor subtypes were defined by joint ER/PR/HER2 status,including Luminal A,Luminal B,Her-2 overexpression and triple-negative breast cancers.The associations between age and fertility factors(including menarche age,age of first full-term pregnancy(FFTP),the interval between menarche and FFTP,number of full-term pregnancies,abortions,lactation,and oral contraceptive(OC)use),as well as the tumor characteristics were determined using the chi-square test.The estimations of the associations between reproductive factors and breast cancer subtypes(luminal A,luminal B,Her-2overexpressing,and TNBC)were determined by multivariate polytomous logistic regression models adjusted by age,age at menarche,age at FFTP,interval between menarche and FFTP,number of full-term pregnancies,abortions,lactation,and oral contraceptive.Results There were significant associations between menarche age,age at first full-term pregnancy(FFTP),the interval between menarche and FFTP,nulliparity,and estrogen receptor(ER)positive tumors(P=0.006,P=0.018,P=0.025,and P=0.007,respectively).A later menarche age(?14 years)and shorter interval(?10 years)were found positively correlated with the odds of developing triple-negative breast cancer(TNBC)(P=0.025 and 0.037,respectively).Additionally,for the women who had ?3 full-term pregnancies,we also observed significantly increased odds of developing Her-2 overexpressing breast cancer(OR: 3.07,95%CI: 1.30-7.25,P=0.011).Compared with the patients who were between 36-40 years old,the patients younger than 35 years were inclined to have a younger menarche age(P<0.001),longer interval(P=0.005),more nulliparity(P<0.001),shorter lactation(P<0.001),more advanced stage(stage III or IV)(P=0.01),and a risk of a higher proportion of HER-2 overexpressing tumors(OR:1.77,95%CI: 1.27-2.48,P<0.001).Conclusions A younger age of FFAP and more full-term pregnancies were found positively correlated with the odds of developing ER negative tumors,and a younger age at menarche was significantly association with ER positive tumors.A later menarche age and shorter interval were found increased risk of developing TNBC,and the cases had more full-term pregnancies was inclined to have a risk of a higher proportion of HER-2 overexpressing tumors.Additionally,the cases with relatively younger age at diagnosis have significantly difference of tumor characteristics and molecular subtypes compared to relatively older cases,as well as different reproductive factors.