Abstract:

Objective To evaluate the value of 21-gene recurrence score（RS） based on different risk stratification criteria in the prognosis assessment of estrogen receptor（ER）-positive，human epidermal growth factor receptor 2（HER-2）-negative Luminal type early invasive ductal carcinoma（IDC） patients. Methods A total of 771 ER-positive，HER-2-negative female IDC patients who underwent surgical treatment at Ruijin Hospital，Shanghai Jiao Tong University School of Medicine from January 2013 to December 2019 were enrolled. The clinical data were collected，and 16 tumor-related genes and 5 reference genes were determined to calculate the 21-gene RS. All the patients were classified into low-risk，intermediate-risk and high-risk groups according to the 21-gene RS grouping criteria of the NSABP B-14 study（low-risk <18 points，intermediate-risk 18-30 points，high-risk >30 points） and the 21-gene RS grouping criteria of the TAILORx trial（low-risk<11 points，intermediate-risk 11-25 points，high-risk>25 points）. The follow-up period was 5 years，and the disease-free survival（DFS） endpoint events were recorded. Multivariate ordinal Logistic regression analysis was used to evaluate the influencing factors of different grouping criteria for IDC patients. The survival situation of IDC patients was evaluated using the Kaplan-Meier survival curve. Results There was statistical significance in PR expression，Ki67 expression，molecular typing，menstrual status and histological grade among the low-risk，intermediate-risk and high-risk groups based on the NSABP B-14 study criteria（P<0.05）. Low PR expression，histological grade Ⅲ and high Ki67 expression were independent risk factors for high-risk 21-gene RS（P<0.05）. There was statistical significance in age，tumor size，PR expression，Ki67 expression，molecular typing，menstrual status，histological grade and clinical stage among the low-risk，intermediate-risk and high-risk groups based on the TAILORx trial criteria（P<0.05）. Low PR expression and histological grade Ⅲ were independent risk factors for high-risk 21-gene RS（P<0.001）. After 5-year follow-up，65 of the 771 IDC patients had DFS endpoint events. There was no statistical significance in 5-year DFS rate among the low-risk，intermediate-risk and high-risk groups based on the NSABP B-14 study criteria（P>0.05）. There was statistical significance in 5-year DFS rate among the low-risk，intermediate-risk and high-risk groups based on the TAILORx trial criteria（P<0.05）. There was statistical significance in 5-year DFS rates among different tumor sizes，histological grades，Ki67 expression，molecular typing and clinical stages（P<0.05）. The intermediate-high-risk and tumor>2 cm based on the TAILORx trial criteria were independent risk factors for poor prognosis in IDC patients（P<0.05）. Conclusions The 21-gene RS is related to PR expression and histological grade in IDC patients. The risk stratification criteria based on the TAILORx trial are more effective for prognosis assessment of IDC patients than those based on the NSABP B-14 study，and it can provide more valuable clinical decision-making basis for ER-positive，HER-2-negative IDC patients.

Key words: 21-Gene recurrence score, Invasive ductal carcinoma, Clinical pathological characteristic, Disease-free survival