Effect of neoadjuvant chemotherapy on breast cancer phenotype, ER/PR and HER2 expression – Implications for the practising oncologist. (June 2016)

• Record Type: Journal Article
• Authors: Gahlaut, Renu; Bennett, Aneliese; Fatayer, Hiba; Dall, Barbara J.; Sharma, Nisha; Velikova, Galina; Perren, Tim; Dodwell, David; Lansdown, Mark; Shaaban, Abeer M.
• Is Part Of: European journal of cancer. Volume 60(2016)
• Page Start: 40
• Page End: 48
• Publication Date: 2016-06
• Subjects: Neoadjuvant chemotherapy -- Breast cancer -- Oestrogen receptor -- Progesterone receptor -- HER2; Cancer -- Periodicals; Neoplasms -- Periodicals; Cancer -- Périodiques; Cancer; Tumors; Electronic journals; Periodicals; Electronic journals; 616.994
• DOI: 10.1016/j.ejca.2016.03.006
• Languages: English
• ISSNs: 0959-8049

Abstract

Abstract: Purpose: To assess the effect of neoadjuvant chemotherapy (NACT) on breast cancer characteristics, hormone receptors and human epidermal growth factor receptor 2 (HER2) expression and whether testing should be repeated on residual tumours. Material and methods: Patients with primary operable breast cancer who received NACT at a single United Kingdom tertiary referral centre were included. Tumour type, grade (including details of mitotic grade, tubule formation and pleomorphism), oestrogen receptor (ER), progesterone receptor (PR) and HER2 status were compared between pre-treatment and post-treatment residual samples using tissue microarrays. A control group of paired core and excision tumours from patients who did not receive NACT was also assessed. Results: Two hundred forty-six cases and 113 controls were included. Pathological complete response (path CR) was achieved in 21.5% of patients. In those patients failing to achieve a path CR, a change in the histological type was noted in 29 out of 178 cases (16.3%, p < 0.001) with increase in the lobular and metaplastic types. Downgrading occurred in 28.8%, due to significant reduction in mitotic rate and prominent tubule formation. A change in ER/PR/HER2 status occurred in 12%, 14.5% and 7.1% of cases, respectively, predominantly as a switch from negative to positive status for ER and from positive to negative status for HER2. Further alterations in expression levels were also noted. Minimal changes in the low ER/PR expressors and the HER2 2+ tumours were found in the control group. Conclusion: Significant changes in tumour morphology, grade, hormone receptors and HER2 status occur following NACT. We recommend testing on residual invasive carcinoma. A switch from negative to positive status warrants offering endocrine/trastuzumab-based therapy to this group of patients. Highlights: Changes in tumour grade, morphology, oestrogen receptor/progesterone receptor/human epidermal growth factor receptor 2 (HER2) status and their level of expression occur following neoadjuvant chemotherapy. We recommend re-testing of residual carcinoma for hormone receptors and HER2. A change from negative to positive marker status offers patients new treatment options.