Potential impact of tumor registry rule changes for recording inflammatory breast cancer

New tumor registry rules for abstracting multiple primaries and histologies include 1 specifically for inflammatory breast cancer (IBC), which states that the International Classification for Oncology (ICD-O) histology code 8530 (3) for IBC should be used only when it is on the pathology report. IBC is typically clinically diagnosed. The purpose of this project is to determine the potential impact of this new rule on identifying IBC cases by searching on the ICD-O histology code.

Two hundred forty patients were identified from The University of Texas M. D. Anderson Cancer Center Tumor Registry database, who had initially presented to the institution from 2005 through 2007 with a diagnosis of IBC.

The basis of diagnosis of IBC was pathologic for 73 patients and clinical for 167. Of the 167 patients with a clinical diagnosis of IBC, 164 patients also had a pathologic diagnosis of a non-IBC histology. Following the new rule, the non-IBC histology would be recorded for these 164 patients.

Based on the analysis of The University of Texas M. D. Anderson Cancer Center's patients with IBC, the new Surveillance, Epidemiology, and End Results multiple primary rule will result in the ICD-O IBC histology code being recorded for approximately 30% of patients with IBC. Clinically diagnosed cases are to be identified using the collaborative staging extension codes or the American Joint Committee on Cancer/TNM classification T value of 4 days. However, many researchers may continue to search only on the histology field, resulting in a perceived decrease in IBC.