Postneoadjuvant therapy: a new approach to the treatment of HER2-positive breast cancer (KATHERINE study results)

• Main Authors: L. G. Zhukova, S. A. Smolin
• Format: Article
• Language: Russian
• Published: Remedium Group LLC 2019-12-01
• Series: Медицинский совет
• Subjects: breast cancer; her2-positive breast cancer; adjuvant therapy; trastuzumab emtansine; t-dm1; katherine; idfs; residual tumor
• Online Access: https://www.med-sovet.pro/jour/article/view/5135

Up until recently, neoadjuvant and adjuvant treatment regimens for breast cancer (BC) were considered equivalent in their effect on long-term treatment outcomes. Despite the fact that additional information on the prognosis of patients (achievement or failure to achieve complete drug pathomorphosis) was obtained during neoadjuvant therapy, we could not change this prognosis, since there was no evidence that any variant of adjuvant therapy could improve survival of patients, who did not achieve complete morphological tumour regression. In December 2018, investigators presented the results of the first planned interim analysis of invasive disease-free survival (iDFS) of patients with early HER2-positive breast cancer, who had residual tumour after neoadjuvant anti-HER2-containing therapy, depending on the adjuvant treatment option: either trastuzumab emtansine (n = 743) or trastuzumab (n = 743). The expected 3-year iDFS in patients, who received trastuzumab emtansine as adjuvant therapy, was 88.3%, while that in the standard trastuzumab group accounted for only 77% (RR = 0.50; 95% CI 0.39–0, 64; h <0.001). The results of the KATHERINE study, which showed an improvement in the survival rates of patients with HER2-positive breast cancer, who did not achieve complete therapeutic pathomorphism (pCR) against the background of neoadjuvant anti-HER2 therapy with the use of trastuzumab emtansine in the adjuvant mode, are not just an important milestone in the treatment of HER2-positive breast cancer. These results reverse the attitude towards neoadjuvant therapy, as we were able, for the first time, to improve the treatment outcome due to the change of the therapy based on therapeutic pathomorphosis data. Thus, this approach leads to the fact that neoadjuvant therapy becomes a more effective technique, at least in HER2-positive breast cancer.