Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2025 Aug;32(8):5510-5520.
doi: 10.1245/s10434-025-17430-6. Epub 2025 May 13.

Trends in the Management of Small HER2-Positive Breast Cancers

Carolin Mueller  1   2 , Rahul Rangan  3 , Megan Kruse  4 , Zahraa Al-Hilli  5
Affiliations

Trends in the Management of Small HER2-Positive Breast Cancers

Carolin Mueller et al. Ann Surg Oncol. 2025 Aug.

Abstract

Background: The treatment approach for small HER2-positive (+) breast cancers seeks to optimize efficacy while minimizing potential overtreatment and associated toxicities. This study aims to evaluate recent trends in treatment patterns for small HER2+ tumors.

Methods: Patients diagnosed with HER2+, cT1, cN0/pN0 breast cancer treated at a single institution from January 2018 to December 2022 were included. Clinicopathological, treatment, and follow-up data were collected and analyzed.

Patients and results: A total of 207 patients were included. Mean age was 63 (± 12.0) years. T category included cT1a in 12.1% (n = 25), cT1b in 28.0% (n = 58), and cT1c in 57.5% (n = 119), while 2.4% (n = 5) had clinical T1 category without further specification. Moreover, 74.4% (n = 154) were hormone receptor positive. Also, 66.7% (n = 138) received adjuvant therapy, 12.6% (n = 26) received neoadjuvant systemic therapy (NAT), and 12.1% (n = 25) received no systemic therapy. Administered regimens included: trastuzumab monotherapy in 6.1% (n = 10), taxane/trastuzumab in 55.5% (n = 91), taxane/carboplatin/trastuzumab in 18.9% (n = 31), and taxane/carboplatin/trastuzumab/pertuzumab in 15.2% (n = 25). In the 26 patients who received NAT, pathological complete response (pCR) was noted in 69.2% (n = 18). Overall, use of NAT increased from 2018 (7.1%) to 2021 (30.2%) and then decreased in 2022 (9.1%). The overall mastectomy rate was 35.3% (n = 73). Young age and multiple tumors were associated with a higher rate of mastectomy (age p < 0.001; multiple tumors p = 0.006). Upstaging of clinically node-negative patients occurred in 14.1% of patients at surgery.

Conclusion: The treatment for cT1N0 HER2+ breast cancers includes primary surgery with adjuvant HER2-targeted therapy in combination with chemotherapy. Primary surgery may allow for an opportunity to deescalate adjuvant therapy with no impact on surgical plan.

Keywords: Adjuvant systemic therapy; Breast cancer; HER2 positive; Neoadjuvant systemic therapy; Treatment patterns.

PubMed Disclaimer

Conflict of interest statement

Disclosure: M.K. was consultant and served on advisory boards for AstraZeneca, GE HealthCare, Genentech, Daiichi Sankyo, Gilead, Stemline Therapeutics, Pfizer. M.K. obtained institutional research funding from AstraZeneca. C.M., R.R., and Z.A. declare no conflicts of interest. Ethical Approval: The study was carried out at the Cleveland Clinic and has been approved by the institutional review board (IRB no. 23-1109, date of approval 31 October 2023).

Figures

Fig. 1
Fig. 1
Clinical tumor category (cT) by year (2018–2022) in n = 207 patients (100%) with T1N0 HER2-positive breast cancer treated at the Cleveland Clinic between January 2018 and December 2022
Fig. 2
Fig. 2
Administration of neoadjuvant and adjuvant therapy from 2018 to 2022 in all patients who received systemic treatment (n = 164) (a) and categorized into those with clinical T1a/b (n = 58) (b) and clinical T1c (n = 102) (c). In four patients who underwent systemic treatment, the specific clinical T1 category could not be determined
See this image and copyright information in PMC

References

    1. Wolff AC, Hammond MEH, Hicks DG, et al. Recommendations for human epidermal growth factor receptor 2 testing in breast cancer: American Society of Clinical Oncology/College of American Pathologists clinical practice guideline update. Arch Pathol Lab Med. 2014;138(2):241–56. 10.5858/arpa.2013-0953-SA. - DOI - PMC - PubMed
    1. Chia S, Norris B, Speers C, et al. Human epidermal growth factor receptor 2 overexpression as a prognostic factor in a large tissue microarray series of node-negative breast cancers. J Clin Oncol. 2008;26(35):5697–704. 10.1200/JCO.2007.15.8659. - DOI - PubMed
    1. Caswell-Jin JL, Sun LP, Munoz D, et al. Analysis of breast cancer mortality in the US—1975 to 2019. JAMA. 2024;331(3):233. 10.1001/jama.2023.25881. - DOI - PMC - PubMed
    1. Piccart-Gebhart MJ, Procter M, Leyland-Jones B, et al. Trastuzumab after adjuvant chemotherapy in HER2-positive breast cancer. N Engl J Med. 2005;353(16):1659–72. 10.1056/NEJMoa052306. - DOI - PubMed
    1. Romond EH, Perez EA, Bryant J, et al. Trastuzumab plus adjuvant chemotherapy for operable HER2-positive breast cancer. N Engl J Med. 2005;353(16):1673–84. 10.1056/NEJMoa052122. - DOI - PubMed

MeSH terms