TNBC vs. Non-TNBC: A Five-Year Retrospective Review of Differences in Mean Age, Family History, Smoking History and Stage at Diagnosis at an Inner City University Program

Background: In recent years, breast cancer has been classified on the basis of estrogen or progesterone receptor (ER/PR) status and whether the human epidermal growth factor 2 receptor (HER2/neu) protein is overexpressed. Based on this system, breast cancer is broadly divided into the triple negative breast cancer (TNBC) and the non-TNBC subtypes. TNBC is a subtype of breast cancer, notable for its propensity to metastasize early and display a comparatively more aggressive course than its non-TNBC counterpart. Certain clinico-pathologic and demographic risk factors have been associated with breast cancer. In this study, we aim to compare mean age, ethnicity, family history, tobacco use and s tage at presentation between TNBC and non-TNBC subtypes at our inner city university program. Methods: We reviewed data in our tumor registry between January 2000 and December 2005 with particular attention to mean age, race, family history, tobacco use and stage at presentation. We found a total of 445 patients with various subtypes of breast cancers. We included only those patients in whom the status of both ER/PR and the status of Her2/neu protein overexpression were recorded. Our strict selection criteria lead to an exclusion of about 103 patients. Out of the remaining 342 patients, 39 were TNBC and 303 were non-TNBC. Results: Mean age of onset for TNBC vs. non-TNBC patients was 59.87 ± 15.67 years vs. 60.09 ± 13.98 years respectively (P = 0.9272). In terms of ethnicity, TNBC vs. non-TNBC patients had the following racial backgrounds: black, 58.97% vs. 39.27%; white, 35.90% vs. 57.76%; Chinese, 2.56% vs. 0.99%; others, 2.57% vs. 1.98% respectively (P = 0.004, OR = 2.755). Comparisons with respect to a history of tobacco abuse for TNBC vs. non-TNBC patients revealed a positive smoking history in 20.51% vs. 27.72% whereas there was no former or current smoking history in 71.79% vs. 61.72% respectively (P = 0.4385). Comparison of family history of a breast cancer in TNBC vs. non-TNBC patients showed that positive family history of breast cancer was seen in 30.77% vs. 33.33%, no family history of cancer was seen in 51.28% vs. 51.82% and unknown 17.95% vs. 14.85% (P = 0.8384). Pathologic stage at the time of diagnosis for TNBC vs. non-TNBC patients was as follows: stage 0, 15.79% vs. 11.37% (P = 0.4332); stage 1, 34.21% vs. 30.98% (P = 0.6890); stage 2, 28.98% vs. 37.25% (P = 0.3205); stage 3, 18.42% vs. 17.25% (P = 0.0.8591); and stage 4, 3.63% vs. 3.14% (P = 0.8651). Analysis using Chi-square test revealed χ 2 value of 0.855. Conclusion: Our results add to the growing body of evidence pertaining to the association of certain demographic and clinico-pathologic characteristics in women with breast cancer. We found that in our patient population, there is a significant ethnic predisposition for the two types of breast cancers that we studied. African Americans were more likely to have TNBC compared to the higher frequency of non-TNBC in white females. We did not find a significant difference in mean age, cigarette smoking, family history and s tage at diagnosis between the TNBC and non-TNBC breast cancer patients. These findings are all consistent with the previously published research studies. World J Oncol. 2013;4(6):241-247 doi: http://dx.doi.org/10.4021/ wjon738w