What is the recommended treatment approach for a patient diagnosed with poorly differentiated invasive carcinoma of the breast?

From the Guidelines

The recommended treatment approach for poorly differentiated invasive carcinoma of the breast involves a multidisciplinary strategy combining surgery, systemic therapy, and radiation, with treatment personalized based on molecular subtype, genomic testing results, tumor stage, and patient factors.

Treatment Overview

The treatment should be carried out in specialized breast units/centres and provided by a multidisciplinary team specialized in breast cancer, consisting of at least medical oncologists, breast surgeons, radiation oncologists, breast radiologists, breast pathologists, and breast nurses (or similarly trained and specialized health care practitioners) 1.

Key Components of Treatment

• Initial treatment usually begins with either breast-conserving surgery (lumpectomy) with sentinel lymph node biopsy or modified radical mastectomy depending on tumor size, location, and patient preference.
• Systemic therapy often includes chemotherapy regimens such as dose-dense AC-T (doxorubicin/cyclophosphamide followed by paclitaxel), TC (docetaxel/cyclophosphamide), or TAC (docetaxel/doxorubicin/cyclophosphamide).
• For HER2-positive disease, targeted therapy with trastuzumab (Herceptin) 6 mg/kg every 3 weeks for one year is added.
• Hormone receptor-positive cases require endocrine therapy such as tamoxifen 20 mg daily for 5-10 years (premenopausal) or aromatase inhibitors like anastrozole 1 mg daily (postmenopausal).
• Radiation therapy typically follows breast-conserving surgery, delivering approximately 50 Gy in 25 fractions.

Personalization of Treatment

Treatment should be personalized based on molecular subtype (determined by ER, PR, HER2 status), genomic testing results, tumor stage, and patient factors, as outlined in guidelines such as those from the National Comprehensive Cancer Network (NCCN) 1.

Multidisciplinary Care

The breast unit/centre should have or be able to refer patients to plastic/reconstructive surgeons, psychologists, physiotherapists, and geneticists when appropriate 1.

Patient Navigation

A breast nurse or a similarly trained and specialized health care practitioner should be available to act as a patient navigator 1.

Ongoing Care and Surveillance

Follow-up care should include regular history and physical exams, mammography, and monitoring for potential side effects of treatment, such as bone health in patients on aromatase inhibitors 1.

From the FDA Drug Label

1.1 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. For the adjuvant treatment of node-positive breast cancer, the recommended regimen is paclitaxel, at a dose of 175 mg/m2 intravenously over 3 hours every 3 weeks for 4 courses administered sequentially to doxorubicin-containing combination chemotherapy

The recommended treatment approach for a patient diagnosed with poorly differentiated invasive carcinoma of the breast is:

• Adjuvant therapy: Ogivri (trastuzumab) in combination with chemotherapy (doxorubicin, cyclophosphamide, and either paclitaxel or docetaxel) for HER2 overexpressing breast cancer.
• Chemotherapy: Paclitaxel at a dose of 175 mg/m2 intravenously over 3 hours every 3 weeks for 4 courses administered sequentially to doxorubicin-containing combination chemotherapy. Key considerations:
• HER2 status: Patient selection should be based on HER2 protein overexpression or HER2 gene amplification in tumor specimens.
• Cardiac function: Evaluate left ventricular function prior to and during treatment with Ogivri.
• Pregnancy: Advise patients of the risks of embryo-fetal toxicity and the need for effective contraception 2.
• Dose adjustments: Reduce the dose of paclitaxel by 20% for patients who experience severe neutropenia or severe peripheral neuropathy 3.

From the Research

Treatment Approach for Poorly Differentiated Invasive Carcinoma of the Breast

The treatment approach for poorly differentiated invasive carcinoma of the breast depends on various factors, including the patient's overall health, tumor size, and hormone receptor status.

• Surgery and radiation therapy are localized therapies for early-stage and metastatic breast cancer 4.
• The management of breast cancer is determined in large part by the HER2, HR, ER, and PR status 4.
• For patients with HR-positive tumors, treatment options include 5-10 years of endocrine therapy and chemotherapy 4.
• Cytotoxic chemotherapeutic agents, such as taxanes, anthracyclines, anti-metabolites, alkylating agents, and drugs that target microtubules, are used to treat HR-negative breast cancer patients 4.
• Targeted approaches, including CDK4/6 inhibitors, PI3K inhibitors, PARP inhibitors, and anti-PDL1 immunotherapy, are used for patients with metastatic breast cancer, depending on the tumor type and molecular profile 4.

Neoadjuvant Therapy

Neoadjuvant therapy with doxorubicin-cyclophosphamide followed by weekly paclitaxel has been shown to be effective in treating early breast cancer 5.

• A retrospective analysis of 200 consecutive patients treated with this regimen found a complete pathologic response rate of 26.0% 5.
• The addition of paclitaxel to doxorubicin/cyclophosphamide has been shown to significantly reduce the hazard for disease-free survival events and improve overall survival 6.

Invasive Ductal Carcinoma

Invasive ductal carcinoma (IDC) is the most common type of breast cancer, and prompt diagnosis and early intervention are crucial for effective treatment 7.

• Various studies have reported on the causes of IDC, including mutations on BRCA1 and BRCA2, different levels of expression of specific genes in signaling pathways, menopause status, alcohol consumption, aging, and hormone imbalances 7.
• Biological markers, such as p-SMAD4 expressions, DNA methylation, and regulations of hub genes, can help identify specific prognoses for IDC patients 7.