Impact of Pathologic Complete Response following Neoadjuvant Chemotherapy ± Trastuzumab in Locally Advanced Breast Cancer

Taher Al-Tweigeri; Mahmoud Elshenawy; Ahmed Badran; Ayman Omar; Kausar Suleman; Osama Al Malik; Ihab Anwar; Noha Jastaniya; Asma Tulbah; Mohammad Al Shabanah; Dahish Ajarim; Adher Al Sayed

doi:10.1155/2021/6639763

Impact of Pathologic Complete Response following Neoadjuvant Chemotherapy ± Trastuzumab in Locally Advanced Breast Cancer

J Oncol. 2021 Feb 12:2021:6639763. doi: 10.1155/2021/6639763. eCollection 2021.

Authors

Taher Al-Tweigeri¹, Mahmoud Elshenawy^{1

2}, Ahmed Badran^{1

3}, Ayman Omar^{1

4}, Kausar Suleman¹, Osama Al Malik⁵, Ihab Anwar⁵, Noha Jastaniya⁶, Asma Tulbah⁷, Mohammad Al Shabanah⁶, Dahish Ajarim¹, Adher Al Sayed¹

Affiliations

¹ Medical Oncology Section, Oncology Centre, King Faisal Specialist Hospital and Research Centre, P.O. Box 3354, Riyadh 11564, Saudi Arabia.
² Clinical Oncology Department, Faculty of Medicine, Menoufia University, Shebin El Kom 32511, Egypt.
³ Clinical Oncology Department, Faculty of Medicine, Ain Shams University, Cairo 11591, Egypt.
⁴ Clinical Oncology and Nuclear Medicine Department, Suez Canal University Hospitals, Ismailia 41522, Egypt.
⁵ Surgical Oncology Department, King Faisal Specialist Hospital and Research Center, P.O. Box 3354, Riyadh 11564, Saudi Arabia.
⁶ Radiation Oncology Section, King Faisal Specialist Hospital and Research Center, P.O. Box 3354, Riyadh 11564, Saudi Arabia.
⁷ Anatomic Pathology Department, King Faisal Specialist Hospital and Research Center, P.O. Box 3354, Riyadh 11564, Saudi Arabia.

Abstract

Purpose: This study was designed to examine the relationship between breast cancer molecular subtypes and pathological response to neoadjuvant chemotherapy (NAC) ± trastuzumab, in locally advanced breast cancer (LABC).

Methods: Female patients with LABC (T2-T4, N0-N2, and M0) who received neoadjuvant chemotherapy + trastuzumab if HER2+ subtype, followed by surgery and radiotherapy ± hormonal therapy, were identified. The primary endpoint was pathologic complete response (pCR) in the breast and axilla (ypT0/ypN0), with final analysis on disease-free survival (DFS) and overall survival (OS).

Results: Six hundred eighty-one patients with a median age of 44 years, premenopausal: 70%, median tumour size: 7.0 cm (range 4-11 cm), stage II B: 27% and III A/III B: 73%, ER+/HER2-: 40.8%, ER-/HER2-: 23%, ER+/HER2+: 17.7%, and ER-/HER2+: 18.5%. Overall pCR (ypT0/ypN0) was 23%. The pCR rates based on molecular subtypes were ER+/HER2-: 9%; ER+/HER2+: 29%; ER-/HER2-: 31%; and ER-/HER2+: 37%. At median follow-up of 61 months, ER+/HER2+ and ER+/HER2- subtypes had the best 5-year DFS and OS; meanwhile, ER-/HER2+ and ER-/HER2- subtypes had the worst.

Conclusion: Women with ER+/HER2- disease are the least likely to achieve pCR, with the highest rates in HER2+ and triple-negative subgroups. Degree of response is associated with OS; despite the comparatively higher likelihood of achieving pCR in ER-/HER2+ and triple-negative, these subgroups experience a survival detriment. We are consistent with the published data that patients who attain the pathological complete response defined as ypT0/ypN0 have improved outcomes.