Study of the Influence of Ductal Carcinoma in Situ on the Outcome of Invasive Breast Cancer
Study of the Influence of Ductal Carcinoma in Situ on the Outcome of Invasive Breast Cancer
A prospective observational longitudinal study of 464 patients was performed between 2010 and
 2015. Patients with invasive ductal carcinoma (IDC) and ductal carcinoma in situ associated
 to invasive ductal carcinoma (DCIS +IDC) were included and analyzed.
Type of study:

 A prospective observational longitudinal study was performed on patients who had undergone
 curative surgery for primary invasive breast cancer between 2010 and 2015. The study was
 performed in a single breast pathology unit [Alt Penedés hospital and Sant Camil
 hospital(GAP)]. Only patients with a definitive histopathology-based diagnostic of ductal
 carcinoma were included. Patients diagnosed with metastasis were excluded. Patients with
 bilateral breast cancer were included as two independent study cases.

 Patients:

 Sample size calculation: 191. A total of 464 patients were included in the study. IDC was
 present in 221 patients (47.6%) and IDC + DCIS was present in 243 patients (52.4%).

 Data collected included clinical characteristics (age, laterality and clinical symptoms at
 the time of diagnostic), histopathological information (tumor size, tumor grade, hormone
 receptors, nodal status, HER-2 mutation (erb-b2 receptor tyrosine kinase 2), number of ki67,
 presence and percentage of DCIS, grade of DCIS, and surrogate subtype) and surgical procedure
 performed.

 Tumor histopathology and the number of lymph nodes involved were evaluated by routine
 hematoxylin-eosin (H&E) staining. The histological response to chemotherapy was assessed
 according to Miller-Payne criteria of grading (MPG) and Residual Disease in Breast and Nodes
 (RDBN).

 The percentage of DCIS and its grade (classified as low, intermediate or high) was measured
 by two independent pathologists.

 Statistical analysis:

 Quantitative data are shown as the median or mean of values and their variability is
 expressed as the range or standard deviation (SD), as specified for each analysis.
 Qualitative data are shown as absolute values or percentages. The incidence was used as a
 measure of frequency and the relative risk as a measure of association between independent
 groups.

 The study of the normality of quantitative variables was done applying the Kolmogorov-Smirnov
 or the Shapiro-Wilk tests, as indicated for each analysis. For significance assessment of
 quantitative data, unpaired Student's T-test or two-tailed Mann-Whitney U test was applied,
 as specified for each analysis. For significance assessment of qualitative data, Fisher's
 exact test or Chi-squared test was applied. For the analysis of more than two groups, one-way
 ANOVA and Tukey's range test for post hoc pairwise comparison of groups, or Kruskal-Wallis
 were used. Survival was analyzed with the Kaplan-Meier estimate and survival distributions
 compared with the Log-Rank test. Multivariate Cox proportional hazards regression model was
 used to simultaneously evaluate the effect of several factors on survival and mortality.

 Statistical analysis was performed using the software SPSS® (Statistical Package for the
 Social Sciences) version 21.

 The aim of the investigator's study is to compare the clinical and histopathological factors
 between patients with IDC or DCIS-associated IDC (IDC + DCIS) and find the prognostic factors
 associated to recurrence and mortality in each group.
Inclusion Criteria:

 -  Patients with invasive ductal carcinoma of the breast

 -  Patients who received surgery for primary invasive breast cancer between 2010 and 2015

 Exclusion Criteria:

 -  Patients with metastasis at the diagnostic