More importantly, small number of patients and low event rates in the female stratum, early stage stratum, and RT alone stratum are significant factors that cannot be ignored.
The software used in this paper (Haberman 2013) treats simple random sampling with replacement, simple stratified random sampling with replacement, two-stage random sampling with both stages with replacement, and stratified random sampling in which, within each stratum, two-stage random sampling is employed with both stages with replacement.
However, we found that the administration of adjuvant chemotherapy varied across the social strata among stage II patients (8% of the lowest SES group versus 17% of the highest SES group, P < 0.001).
A minimum of 50 patients per stratum (TNM stages I, II and III) was requested to conduct the evaluation of the algorithm in order to cover a variety of care trajectories of patients with breast cancer.
Cox regression, adjusted for age, year of diagnosis, grade, and ER/PR/HER2 subtype, was used to assess the association of race/ethnicity on breast cancer-specific mortality within strata of stage and SES.
Instead, for BRCA1 the effect of GPS was protective (RH = 0.76, p = 0.01) in the whole BRCA1 population and in the ovulating stage stratum (also protective but not significant at the 0.05 level in the menopausal stratum).
This may mainly result from a large number of patients and high event rates in the advanced clinical stage stratum; the interactions between clinical stage and a first-degree family history of NPC (P<0.001) may also contribute to it.
In addition, in order to determine whether intratumoral GalNAc-T5 expression could stratify patients with TNM stage stratum, we evaluated the prognostic value of intratumoral GalNAc-T5 expression and performed stratified analyses of gastric cancer patients with TNM stage I+II and TNM stage III+IV, respectively.
To ensure appropriate representation of each stratum, a two-stage stratification sampling method was applied to minimize heterogeneities among groups (strata).
The association with BMI at age 30 was consistent in different strata of pathological stage and Gleason score (Table 4).
