From the Guidelines
The treatment for T1 or T2 breast tumors typically involves surgery as the primary approach, either breast-conserving surgery (lumpectomy) or mastectomy depending on tumor characteristics and patient preference. For lumpectomy, whole breast radiation therapy is usually recommended afterward, typically delivered over 3-6 weeks 1. Systemic therapy decisions depend on tumor biology: hormone receptor-positive tumors generally receive endocrine therapy (such as tamoxifen for 5-10 years or aromatase inhibitors like anastrozole, letrozole, or exemestane for postmenopausal women); HER2-positive tumors typically receive anti-HER2 targeted therapy (trastuzumab for one year, often with pertuzumab); and chemotherapy is considered based on factors like tumor grade, size, lymph node involvement, and genomic testing results (such as Oncotype DX) 1.
Key Considerations
- Tumor size and characteristics play a significant role in determining the treatment approach, with T1 or T2 tumors being candidates for breast-conserving surgery or mastectomy 1.
- The decision to use trastuzumab and chemotherapy in patients with HER2-positive, node-negative tumors measuring 0.6 to 1.0 cm (T1b) is supported by studies showing a higher risk of recurrence in these patients 1.
- The NCCN panel recommends considering either level I and II axillary dissection or no further axillary surgery for patients with T1 or T2 tumors and 1 to 2 positive SLNs, who did not receive neoadjuvant therapy, and are treated with lumpectomy and whole breast radiation 1.
Treatment Options
- Breast-conserving surgery (lumpectomy) followed by whole breast radiation therapy
- Mastectomy
- Systemic therapy, including endocrine therapy, anti-HER2 targeted therapy, and chemotherapy
- Axillary dissection or sentinel lymph node biopsy to assess lymph node involvement
Recent Guidelines
The most recent guidelines from the NCCN (2024) support the use of trastuzumab and chemotherapy in patients with HER2-positive, node-negative tumors measuring 0.6 to 1.0 cm (T1b) 1. These guidelines also emphasize the importance of considering tumor biology and patient factors when making treatment decisions.
From the FDA Drug Label
- 1 Adjuvant Breast Cancer Ogivri is indicated in adults for adjuvant treatment of HER2 overexpressing node positive or node negative (ER/PR negative or with one high risk feature [see Clinical Studies (14. 1)]) breast cancer as part of a treatment regimen consisting of doxorubicin, cyclophosphamide, and either paclitaxel or docetaxel as part of a treatment regimen with docetaxel and carboplatin as a single agent following multi-modality anthracycline based therapy.
The treatment for T1 or T2 breast tumors is adjuvant therapy with a regimen consisting of:
- Doxorubicin
- Cyclophosphamide
- Either paclitaxel or docetaxel
- Or docetaxel and carboplatin as a single agent following multi-modality anthracycline-based therapy. This is for HER2 overexpressing node positive or node negative breast cancer, and patients should be selected based on an FDA-approved companion diagnostic for a trastuzumab product 2.
From the Research
T1 or T2 Breast Tumors
- T1 and T2 breast tumors refer to the size of the tumor, with T1 being smaller (up to 2 cm) and T2 being larger (more than 2 cm but not more than 5 cm) 3, 4, 5.
- The treatment for T1 or T2 breast tumors often involves breast-conserving therapy, which includes wide local tumor excision or quadrantectomy and breast irradiation 3, 4, 6.
- Breast-conserving therapy is widely accepted as an appropriate method of primary treatment for T1 and T2 breast cancers that measure up to 5 cm 3.
- For patients with T1 and T2 tumors, the overall local tumor recurrence rates were 5% and 11%, respectively, with no significant difference in the breast relapse rate in patients treated with either electron beam or interstitial 192Ir boost 4.
- The 10-year actuarial disease-free survival rates were 87% for patients with T1 and 75% with T2 tumors, with disease-free survival being exactly the same in patients receiving either electron beam or interstitial 192Ir boost 4.
Treatment Options
- Breast-conserving surgery plus radiation therapy (RT) yields overall survival outcomes equivalent to those achieved with mastectomy 6.
- Selected patients, such as those older than 70 years of age with hormone receptor-positive T1 tumors who are willing to commit to receiving adjuvant endocrine therapy, may be able to forgo RT completely 6.
- Advances in pathologic evaluation, management of multiple tumors, oncoplastic lumpectomy techniques, neoadjuvant chemotherapy, and hypofractionated RT can expand the pool of patients eligible for breast-conserving surgery 6.
- For patients with small (T1mic, T1a, and T1b), node-negative, HER2-positive breast cancer, the use of anti-HER2 treatment regimens is still a topic of debate, with some studies suggesting that high-risk T1b and T1c subgroups derive measurable added benefit from HER2-guided combination therapies 7.
Risk Factors
- Clinical and pathologic factors, such as age, histologic findings, tumor location, size, and grade, lymphovascular invasion status, estrogen receptor (ER) status, margin status, number of positive nodes, and systemic therapy use, can identify women with T1-T2 breast cancer and one to three positive nodes at high locoregional recurrence risk 5.
- Age <45 years, >25% of nodes positive, a medial tumor location, and ER-negative status were statistically significant independent factors associated with greater locoregional recurrence risk, meriting consideration and discussion of postmastectomy radiotherapy (PMRT) 5.