Ethnicity Impact on the Outcome of Surgery versus Combined Therapy with Surgery and Radiotherapy in Localized Breast Cancer

Signature Grand, Davie, Florida, USA

Objectives. What is the effect of ethnicity on the outcome of combined treatment (surgery plus radiotherapy) versus surgery alone? Background. Breast cancer is the most common female cancer and the second most frequent cause of cancer related death in females in the United States. Over 210,000 cases of invasive breast cancer will be diagnosed in women in the United States within the calendar year. Methods. Patients diagnosed for the first time with breast cancer in the state of Florida between January 1, 1995 and December 31, 2002 were studied in this analysis. A total of 55, 564 patients with localized breast carcinoma and ductal or lobular carcinomas were analyzed based on their vital status (death vs alive) and treatment (surgery+radiotherapy vs. surgery alone). The Mantel- Haenszel stratified analysis was used to assess confounders and effect modifiers. The relative risk (RR) was used to measure the association between treatment and outcome. Results. Patients that underwent surgery alone were two times more likely to die than patients who underwent both surgery and radiotherapy . Histology and ethnicity were found to modify the effect of the association between breast cancer treatment and outcome. Controlling for both, ethnicity and histology, the most significant finding was that African-Americans had a higher risk of death if they undergo surgery alone for localized ductal carcinoma compared to Caucasians. Conclusion. The results are limited because we were unable to compare lobular carcinoma across ethnicity due to non-significant associations. For African-Americans and Caucasians with ductal carcinoma, the advisable treatment would be surgery and radiotherapy as this has a lower risk of mortality.