Invasive ductal carcinoma and invasive lobular carcinoma of breast differ in response following neoadjuvant therapy with epidoxorubicin and docetaxel + G-CSF.

PURPOSE: Preoperative chemotherapy in patients with primary breast cancer treated with anthracyclines and taxanes results in high response rates, allowing breast conserving surgery (BCS) in patients primarily not suitable for this procedure. Pathological responses are important prognostic parameters for progression free and overall survival. We questioned the impact of histologic type invasive ductal carcinoma (IDC) versus invasive lobular carcinoma (ILC) on response to primary chemotherapy. PATIENTS AND METHODS: 161 patients with breast cancer received preoperative chemotherapy consisted of epidoxorubicin 75 mg/m(2) and docetaxel 75 mg/m(2) administered in combination with granulocyte-colony stimulating factor (G-CSF) on days 3-10 (ED + G). Pathological complete response (pCR), biological markers and type of surgery as well as progression free and overall survival were compared between IDC and ILC.
RESULTS: Out of 161 patients, 124 patients presented with IDC and 37 with ILC. Patients with ILC were less likely to have a pCR (3% vs. 20%, P < 0.009) and breast conserving surgeries (51% vs. 79%, P < 0.001). Patients with ILC tended to have oestrogen receptor positive tumors (86% vs. 52%, P < 0.0001), HER 2 negative tumors (69% vs. 84%), and lower nuclear grade (nuclear grade 3, 16% vs. 46%, P < 0.001). Patients with ILC tended to have longer time to progression (TTP) (42 months vs. 26 months) and overall survival (69 months vs. 65 months).
CONCLUSIONS: Our results indicate that patients with ILC achieved a lower pCR rate and ineligibility for BCS to preoperative chemotherapy, but this did not result in a survival disadvantage. Because of these results new strategies to achieve a pCR are warranted.