From the Guidelines
The recommended treatment for ER+/PR+ lobular carcinoma of the breast is a multidisciplinary approach, including surgery, adjuvant endocrine therapy with tamoxifen or aromatase inhibitors, and potentially chemotherapy or targeted therapy, as outlined in the most recent guidelines 1.
Treatment Approach
The treatment of ER+/PR+ lobular carcinoma of the breast involves:
- Surgery: either breast-conserving surgery (lumpectomy) with radiation therapy or mastectomy, depending on tumor size, location, and patient preference.
- Adjuvant endocrine therapy:
- Tamoxifen (20mg daily for 5-10 years) for premenopausal women.
- Aromatase inhibitors such as anastrozole (1mg daily), letrozole (2.5mg daily), or exemestane (25mg daily) for 5-10 years in postmenopausal women.
- Sequential therapy (tamoxifen followed by an aromatase inhibitor) may be beneficial for some patients.
- Chemotherapy may be added for higher-risk disease based on tumor size, lymph node involvement, grade, and genomic testing results (like Oncotype DX).
- Targeted therapy with CDK4/6 inhibitors (palbociclib, ribociclib, or abemaciclib) may be added for metastatic disease, as recommended by recent guidelines 1.
Rationale
This comprehensive approach targets hormone-dependent cancer growth since ER+/PR+ tumors rely on estrogen and progesterone for proliferation. The use of tamoxifen and aromatase inhibitors has been shown to decrease the annual odds of recurrence and death in patients with ER-positive breast cancer 1. Regular follow-up with oncology is necessary to monitor treatment response and manage side effects.
Key Considerations
- Patient preference is a major component of the decision-making process, especially when survival rates are equivalent among the available treatment options 1.
- Treatment should be based on the biology of the tumor and the menopausal status of the patient, with careful attention paid to ovarian production of estrogen 1.
From the Research
Treatment Options for ER+PR+ Lobular Carcinoma of the Breast
- The treatment for Estrogen Receptor positive (ER+) and Progesterone Receptor positive (PR+) lobular carcinoma of the breast depends on various factors, including the stage and size of the tumor, as well as the patient's overall health and preferences 2, 3.
- Lumpectomy followed by radiation therapy is a possible treatment option for patients with ER+PR+ lobular carcinoma, as it has been shown to be effective in reducing the risk of local recurrence and improving overall survival 2.
- A study published in 1996 found that patients with invasive lobular carcinoma who were treated with lumpectomy and radiation had a low risk of local recurrence and equivalent overall survival compared to those who underwent modified radical mastectomy 2.
- Another study published in 2021 found that breast cancer survivors who underwent lumpectomy reported higher satisfaction with cosmetic outcomes, but also experienced more radiation side-effects, including skin thickening and chronic pain 4.
- The use of endocrine therapy, such as tamoxifen, is also a common treatment approach for ER+PR+ lobular carcinoma, as most of these tumors exhibit estrogen receptor positivity and Her2 neu negativity 3.
- Novel treatments, such as CDK4/6 inhibitors and antibody drug conjugates, may also be effective in treating ER+PR+ lobular carcinoma, particularly in patients with Her2 low breast tumors 3.
Factors Influencing Treatment Outcomes
- Age is an important factor in determining treatment outcomes for ER+PR+ lobular carcinoma, with patients diagnosed at young or old ages having a worse prognosis compared to those in the middle ages 5.
- The prognostic value of age varies depending on the ER and PR-defined subtype, with patients with ER+PR+ subtype having a worse prognosis at young and old ages 5.
- Multivariate analysis has shown that patients with ER+PR+ subtype have a higher risk of mortality with increasing age, particularly in those older than 79 years 5.