Objective:To investigate the high-risk factors affecting the prognosis of patients with pT 1-2N 1M 0 after mastectomy, establish a nomogram prediction model, perform risk stratification, and screen the radiotherapy benefit populations. Methods:Clinical data of 936 patients with pT 1-2N 1M 0 breast cancer undergoing mastectomy in the Fourth Hospital of Hebei Medical University from January 2010 to December 2016 were retrospectively analyzed and 908 cases had complete follow-up data. They were divided into the radiotherapy (RT) group ( n=583) and non radiotherapy (NRT) group ( n=325) according to the radiotherapy. After propensity score matching (PSM) was performed 1 vs. 1, 298 cases were assigned into the RT group and 298 in the NRT group. Overall survival (OS) and disease-free survival (DFS) were compared between two groups using log-rank test. Nomogram prediction model was established, the survival differences were compared among different risk groups, and the radiotherapy benefit populations were screened. Results:Univariate analysis showed that the 5- and 8-year OS and DFS in the RT group were significantly better than those in the NRT group (both P<0.001). Multivariate analysis showed that age, tumor quadrant, number of lymph node metastases, T staging, and Ki-67 level were the independent prognostic factors for OS. Age, tumor quadrant, and T staging were the independent prognostic factors for DFS. The OS nomogram analysis showed that the OS of patients in the high-risk group was significantly improved by post-mastectomy radiotherapy (PMRT) ( P=0.001), while PMRT did not show an advantage in the low- and medium-risk groups ( P=0.057, P=0.099). The DFS nomogram analysis showed that DFS was significantly improved by PMRT in patients in the medium- and high-risk groups ( P=0.036, P=0.001), whereas the benefits from PMRT were not significant in the low-risk group ( P=0.475). Conclusions:For patients with pT 1-2N 1M 0 breast cancer after mastectomy, age ≤ 40 years, tumor located in the inner quadrant or central area, T 2 staging, 2-3 lymph node metastases, Ki-67>30% are the high-risk factors affecting clinical prognosis. The nomogram prediction model can screen the populations that can benefit from PMRT, providing reference for clinical decision-making.

Objective:To study the effects of the apical dentin surface morphology resected with Er∶YAG laser on the proliferation of human periodontal ligament cells(hPDLCs).Methods:66 single premolars were randomly divided into 3 groups(n=22),and the api-cal root slices were made by resection perpendicular to the root long axis 3 mm from the apex using high-speed handpiece(group A),piezosurgery(group B)and Er∶YAG laser(group C),respectively.SEM was used to observe the apical dentin surface in the aspects of debris,smear layer,dentinal tubules,cracks,ablation characteristics and the dentin surface roughness was measured.hPDLCs were clutured on the surface of the slices of the groups,CCK-8 method was used to detect cell proliferation on the samples at 24,48 and 72 h of culture,respectively.Results:The surface preparition time of group A was shorter than that of group B and C(P＜0.001).SEM observation showed that in group C,there was no residual debris or stained layer,and dentin tubule was visible on the dention sur-faces.Detritus and stained layers were observed in group A and B,and dentin tubule was not observed in group A.Cracks were observed in all the groups,but less in group C.Roughness(nm)of group C(1 487.13±295.90)was higher than that of group A and B(P＜0.001).CCK-8 assay showed that the cell proliferation(A value)of all groups increased gradually with the culture time after 24,48 and 72 h of hPDLCs seeded on the root surface.And the cell proliferation in group C was the most significant than that in group A and B(P＜0.05)at 48 and 72 h.Conclusion:The morphological performance of the apical dentin surface resected with Er∶YAG laser is more conducive to hPDLCs growth than that with the ultrasound and burs.