The impact of Oncotype DX^® recurrence score of paraffin-embedded core biopsy tissues in predicting response to neoadjuvant chemotherapy in women with breast cancer

Article type: Research Article

Authors: Soran, Atilla^{a; *} | Bhargava, Rohit^b | Johnson, Ronald^a | Ahrendt, Gretchen^a | Bonaventura, Marguerite^a | Diego, Emilia^a | McAuliffe, Priscilla F.^a | Serrano, Merida^b | Menekse, Ebru^a | Sezgin, Efe^c | McGuire, Kandace P.^a

Affiliations: [a] Department of Surgery, Division of Surgical Oncology, University of Pittsburgh, Pittsburgh, PA, USA | [b] Department of Pathology, Magee-Womens Hospital of UPMC, University of Pittsburgh, Pittsburgh, PA, USA | [c] Department of Food Engineering, Laboratory of Nutrigenomics and Epidemiology, Izmir Institute of Technology, Izmir, Turkey

Correspondence: [*] Corresponding author: Atilla Soran, Magee-Womens Hospital of UPMC, Suite 2601, 300 Halket Street, Pittsburgh, PA 15213, USA. Tel.: +1 412 641 4538; Fax: +1 412 641 1446; E-mail: [email protected]

Abstract: BACKGROUND:Oncotype DX® test is beneficial in predicting recurrence free survival in estrogen receptor positive (ER+) breast cancer. Ability of the assay to predict response to neoadjuvant chemotherapy (NCT) is less well-studied. OBJECTIVE:We hypothesize a positive association between the Oncotype DX® recurrence score (RS) and the percentage tumor response (%TR) after NCT. METHODS:Pre-therapy RS was measured on core biopsies from 60 patients with ER+, HER2− invasive breast cancer (IBC) who then received NCT. Pre-therapy tumor size was measured using imaging. %TR, partial response (PR; >50%), pathologic complete response (pCR) and breast conserving surgery (BCS) rates were measured. RESULTS:Median RS was 20 (2–69). Median %TR was 42 (0–97)%. PR was observed in 43% of patients. There was no association between %TR and pre-NCT tumor size, age, Nottingham score or nodal status (p > 0.05). No statistically significant association with %TR was seen with RS as a categorical or continuous variable (p = 0.21 and 0.7, respectively). Response to NCT improved as ER (p = 0.02) by RT-PCR decreased. Lower ER expression by IHC correlated with response (p = 0.03). CONCLUSIONS:In patients with ER+ IBC receiving NCT, RS did not predict response to NCT using %TR. The benefit of the assay prior to NCT requires further study.

Keywords: Estrogen positive, 21 gene assay, tumor volume reduction, breast cancer, neoadjuvant, response

DOI: 10.3233/BD-150199

Journal: Breast Disease, vol. 36, no. 2-3, pp. 65-71, 2016