Comparison Of Clinicopathological Characteristics And Prognosis Of Breast Cancer Patients Between Age Of Under 25 And Of 26～35 Upon Diagnosis

Objective:We aimed to compare the clinicopathological characteristics and prognosis between breast cancer patients diagnosed below 25 years old and patients aged 26～35 years old.Further we conducted a survival analysis and explored the survival-age relationship.Method:We collected the data of young female breast cancer patients treated in Cancer Hospital Chinese Academy of Medical Sciences from January Ist,2000 to December 31st,2016 retrospectively.We defined patients below 25 years as young group and patients aged 26～35 years as elder group.By random sampling we collected 122 patients in young group and 448 patients in elder group.The differences in clinical diagnosis,pathological characteristics,therapies and results of follow-up were analyzed using SPSS 22.0.Further exploration of survival-age relationship was conducted using SAS 9.4.Results:1.Clinical characteristics:The median diagnostic delay was longer in young group(3.0 months vs.2.0 months,P=0.030).Family history,pregnancy-associated breast cancer,bilateral synchronous breast cancer had no significant difference in two groups(P>0.05).2.Pathological characteristics:Young group presented with more breast cancer in situ than elder group(8.0%vs.3.6%,P=0.041).With regard to histological grade,estrogen receptor(ER),progesterone receptor(PgR),human epidermal growth factor receptor-2(HER2),molecular subtype and tumor stage,there was no significant differences between young group and elder group(P>0.05).But pregnancy-associated breast cancer patients had less ER/PgR positive tumor(42.9%vs.71.4%,P<0.001),higher percentage of Ki-67>30%(57.7%vs.36.8%,P=0.037),more primary metastasis tumor(18.2%vs.1.2%,P<0.001)and more of whom received neoadjuvant therapy(55.65 vs.12.7%,P<0.001).3.Therapies:Patients in young group tended to choose breast-conserving surgery more than elder group(55.0%vs.34.4%,P<0.001),with more radiotherapies(74.7%vs.63.0%,P=0.034).No difference was observed in the choice of neoadjuvant therapy,chemotherapy,immunotherapy and target therapy between two group(P>0.05).4.Prognosis:There was no significant difference between young group and elder group regarding disease free survival(DFS)and overall survival(OS)in both invasive cancer and tumor in situ(P>0.05).In multivariable analysis,ER/PgR positive(HR=0.667,95%CI 1.047-3.358),tumor size>2cm(HR=1.661,95%CI 1.132-2.421),lymph node metastasis>3(HR=1.6555 95%Cl 1.146-2.406)and neoadjuvant therapy(HR=1.949,95%CI 1.274-2.988)were found to correlate to the DFS.ER/PgR positive(HR=0.443,95%CI 0.268-0.734),lymph node metastasis>3(HR=3.046,95%CI 1.825-5.028)and neoadjuvant therapy(HR=1.876,95%CI 1.047-3.358)were found to correlate to the OS.Age was not correlate to either DFS or OS.In the subtype of patients with breast-conserving surgery,young group was observed to have poorer outcome in both DFS(P=0.011)and OS(P=0.004).The relationship between death hazard and age was continuous(HR=0.929,95%CI 0.871-0.990),best fitted by a In-linear function,and showing a 7.1%decrease in death for every year of increase in age.Conclusion:Breast cancer patients diagnosed below 25 years old had a longer median diagnostic delay,higher percentage of tumor in situ,and more likely to receive breast-conserving surgery and radiotherapy compared to elder patients.With regard to DFS and OS,no significant difference was observed between the two group.After multivariable analysis,age was not shown to correlate to either DFS or OS.But the relationship between death hazard and age was continuous with a 7.1%decrease in death for every year of increase in age.