Abstract P6-06-31: Prognostic factors and outcomes in triple negative breast cancer - A single institution experience

Abstract

Abstract Background: Triple negative breast cancer (TNBC) is characterized by the lack of estrogen, progesterone, and human epidermal growth factor receptor (HER 2) expression. TNBC tumors appear to show aggressive clinical behavior with an increased risk of recurrence. Patients may undergo adjuvant or neoadjuvant chemotherapy depending on their tumor size. The aim of our study is to identify prognostic factors that impact disease free interval (DFI). Materials and Methods: All patients with TNBC from 2006 to 2011 were identified using the MCC Cancer Registry. Individual charts were reviewed for further validation of data and 484 patients were found to be eligible for our retrospective analysis. DFI was calculated as the interval between end of treatment after diagnosis and first recurrence. Patients were classified into two subgroups based on DFI, <3 yrs. and DFI≥3 yrs. 194 patients were excluded when interpreting the DFI as the follow up period was <3 yrs. Multiple characteristics such as race, clinical and pathologic tumor size, type of surgery, radiation, age of menarche, gravida status, and body mass index (BMI) were reviewed, and compared using Wilcoxon Rank Sum Test for continuous variables and Chi-square test for categorical variables. Survival analysis was also performed on all eligible patients. Results: 395(82%) patients were identified as white, 63(13%) were black and 26(5%) were grouped as other. 360(74%) patients were placed in the non-recurred and 124(26%) in the recurred group. 368(76%) patients received adjuvant and 116(24%) were treated with neoadjuvant chemotherapy. The mean follow up time for all patients was 2.52 years. The mean pathologic tumor size was 2.37 cm and clinical tumor size was 2.8 cm. 26% of the patients had recurred at 3yr follow-up. Clinical and Pathologic tumor size variables were significant among both the DFI groups (p<0.0001). Pathologic tumor size was marginally higher in the adjuvant (n = 357) vs. neoadjuvant (n = 90) setting (p = 0.0679) across all patients. Of the 45 patients who underwent lumpectomy, 5 (11%) patients recurred (P-value <0.0001) with a 3yr DFI estimate (95% CI, 0.68-0.94) of 0.86. A total of 140 patients received radiation after lumpectomy; of which 23 (16%) patients developed recurrent disease, with a 3yr DFI estimate (95% CI, 0.78-0.91) of 0.86. 143 patients underwent mastectomy without radiation of which 28 (20%) of them recurred with a 3yr DFI estimate (95% CI, 0.72-0.86) of 0.80. 147 patients underwent mastectomy followed by radiation of which 64 (45%) patients in this group recurred with a 3yr DFI estimate (95% CI, 0.45-0.64) of 0.55. Conclusions: The risk of recurrence increases in proportion with regional lymph node involvement more specifically with ≥3 lymph nodes. Patients who received neoadjuvant chemotherapy also have a higher risk of recurrence, possibly secondary to larger clinical tumor size. Interestingly, gravida status of ≥3 was associated with prolonged survival and a reduced risk of recurrence. Patients who underwent lumpectomy followed by radiation had improved survival over patients who had mastectomy (with or without radiation). Other epidemiologic factors were reviewed including age of menarche and BMI which were not found to be associated with increased risk of recurrence. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-31.