Context: case–control study
Over the past 5 years, an epidemiologic case–control study was developed and conducted by several of the co-authors in Egypt, Tunisia, and Morocco to enroll IBC patients based on clinical evidence and investigate the epidemiology of the disease. The Tanta Cancer Center (TCC) and the Gharbiah Cancer Society (GCS) were the sources of patients for the Gharbiah study site in Egypt. Patients were recruited and enrolled if (A) they were female, Egyptian, and at least 18 years old; (B) had erythema and/or edema/peau d’orange in at least one-third of the breast; (C) did not have extensive ulceration; (D) had pathologic confirmation of cancer; (E) had no previous treatment for the present breast cancer, and; (F) had no history of breast cancer. The patients enrolled in this study were confirmed as IBC using the signs/symptoms present during clinical examinations in addition to pathological confirmation of cancer. During the period of 2009–2010, 40 patients were recruited from TCC and GCS and each case was given a unique study ID number.
Data collection
As part of the case–control study, information on signs and symptoms associated with diagnosis of IBC was collected at the time of diagnosis on standardized forms based on the clinical examination by physicians participating in the case–control study. Information collected included the presence, extent, and duration of erythema, peau d’orange, and increase in breast size. In addition, information was collected on the following signs/symptoms of breast cancer that might be helpful in distinguishing IBC from other types of locally advanced breast cancer that are characterized by neglect and delayed diagnosis: the presence, size, and duration of a palpable mass, ulceration, and palpable axillary lymph nodes.
Abstraction forms were developed and used to identify possible IBC cases from medical records of the 2 study hospitals (TCC and GCS) during the same time period as the case–control study (2009–2010). The medical records collected included all patients who received neoadjuvant chemotherapy for breast cancer treatment at the same institutions. The same variables collected in the case–control study were included in the medical record abstraction.
Data analysis
Data analysis focused on: (A) identifying the IBC cases included in the case–control study who had medical records available; (B) identifying the concordance between the signs/symptoms collected for the case–control study and the signs/symptoms recorded on the routine medical records; (C) calculating sensitivity and specificity for signs recorded in the medical records compared to those recorded for the case–control study, and; (D) performing McNemar’s tests for each symptom to determine if there was a significant difference between the two data sources, taking into account the paired nature of the data. A p value less than 0.05 suggested significant discordance. In this study, peau d’orange and edema were combined and analyzed together as peau d’orange. Similarly, erythema and inflammation were combined and analyzed as erythema. All statistical analysis was performed using SAS 9.2 (Cary, NC).
Medical records were available for 34 (85%) of the 40 cases that were recruited in the case–control study. The 6 remaining cases did not have medical records from GCS or TCC due to receiving treatment elsewhere. There were a number of additional variables abstracted from the medical records that were excluded from analysis in the present study, including the name of the examining physician for each patient, which is referenced in the discussion. The study was approved by the University of Nebraska Medical Center IRB Committee (Protocol 060-13-EX) and the Gharbiah Cancer Society IRB Committee in Egypt. No patients were approached for this study and the secondary analysis of data of the medical records did not include any data of children. The consent was waived by the IRB Committees listed above in Egypt and Nebraska because of the secondary analysis of the aggregate data of the study.