Different responses to preoperative chemotherapy for invasive lobular and invasive ductal breast carcinoma

Aim: Preoperative chemotherapy (PCT) is used in primary breast cancer, to facilitate breast conservative surgery (BCS). Clinical and pathologic responses are important prognostic parameters. Biologic markers are needed to individualize treatment. Patients and Methods: One hundred and thirty-five patients with breast carcinoma were treated with PCT, followed by surgery and adjuvant therapy. Clinical response and pathological complete response (pCR), biological markers and type of surgery were compared between invasive ductal (IDC) and invasive lobular carcinoma (ILC). Results: Overall response (OR) for IDC was 75% compared to 50% for ILC (P=0.0151). Pathological CR was 15% for IDC and 0% for ILC (P=0.0066). Fifty-six percent of the responding patients had BCS, in contrast with 16% of the non-responders. BCS was performed in 50% of patients with IDC, in 38% of the patients with ILC. Salvage surgery was more necessary in ILC (19%) compared to IDC (4%) (P=0.0068). Patients with ILC were more frequently ER-positive and HER-2 negative than patients with IDC. Conclusions: Clinical and pathological responses are lower in ILC compared to IDC. After PCT, patients with large ILC should preferably be offered mastectomy with immediate breast reconstruction. However, PCT still remains valuable to evaluate tumor response and biologic factors in vivo.