This guide explains how hormone and targeted therapy are used for hormone receptor-positive and BRCA-related breast cancer, including CDK4/6 inhibitors, PARP inhibitors, and newer biomarker-matched treatments, covering eligibility, side effects, monitoring, and care coordination in Germany.

Hormone and Targeted Therapy for Breast Cancer in Germany: Treatment Options

Hormone and targeted therapies have expanded breast cancer treatment in Germany beyond chemotherapy by acting on the biological features that drive each tumor. Endocrine therapies block estrogen-receptor signaling or estrogen production in hormone receptor-positive cancers, while targeted therapies act on specific proteins or pathways involved in tumor growth. Treatment selection in Germany depends on biomarkers, disease stage, previous treatment, and the patient’s overall health, with the appropriate combination determined as part of an individualized treatment plan.

Hormone Therapy for Hormone Receptor-Positive Breast Cancer

Endocrine therapy is a mainstay of treatment for hormone receptor-positive breast cancer, in which the cancer cells express estrogen receptors, progesterone receptors, or both, as shown by pathology testing. After surgery, it reduces the risk of recurrence [1].

Neoadjuvant endocrine therapy, usually an aromatase inhibitor given before surgery, may be considered for selected postmenopausal patients when chemotherapy is not suitable. In recurrent or metastatic disease, endocrine therapy, alone or with targeted drugs, can control the cancer for as long as it remains effective [4].

Hormone Therapy Before and After Menopause

Menopausal status, recurrence risk, tumor characteristics, previous treatment, and tolerability help determine which endocrine therapy is used:

• Premenopausal patients: Tamoxifen is commonly used. For patients at higher risk of recurrence, ovarian function suppression with a GnRH agonist such as goserelin may be added to tamoxifen or combined with an aromatase inhibitor.
• Postmenopausal patients, and premenopausal patients receiving ovarian function suppression: Aromatase inhibitors such as letrozole, anastrozole, or exemestane reduce estrogen production in peripheral tissues. Tamoxifen is also an established endocrine therapy and may be used when an aromatase inhibitor is not suitable or as part of a sequential treatment strategy [1].

Long-Term Hormone Therapy and Treatment Duration

Adjuvant endocrine therapy is usually given for at least five years. Extending tamoxifen to ten years can further reduce recurrence and mortality in selected patients, particularly those with a substantial risk of late recurrence. An aromatase inhibitor may also be continued beyond five years in selected higher-risk postmenopausal patients, weighed against cumulative effects such as bone loss [1]. The decision to extend, switch, or stop treatment is reviewed periodically with the care team.

Targeted Therapy Options for Breast Cancer

• Unlike chemotherapy, which affects rapidly dividing cells throughout the body, targeted therapies interfere with specific proteins or pathways that a tumor depends on, although they can still cause significant side effects.
• Many targeted therapies are selected according to a specific biomarker or receptor status, together with the disease setting and previous treatment. CDK4/6 inhibitors do not require a separate mutation test such as for PIK3CA or ESR1; their use is based on factors including hormone receptor-positive, HER2-negative disease and the clinical setting.
• Some targeted treatments depend on inherited BRCA mutations, while others are guided by alterations found through tumor testing.

This section focuses on hormone receptor-positive and BRCA-related targeted options; HER2-targeted therapy is covered separately.

Hormone Receptor-Positive Disease

For hormone receptor-positive, HER2-negative breast cancer, CDK4/6 inhibitors are among the most established targeted options.

Two have approved adjuvant indications for selected patients with high-risk, hormone receptor-positive, HER2-negative early breast cancer:

• Abemaciclib may be added to adjuvant endocrine therapy for two years. The monarchE trial enrolled patients with four or more positive lymph nodes, or one to three positive nodes plus a high-risk feature such as grade 3 disease, a tumor 5 cm or larger, or a Ki-67 index of 20% or higher. The EU authorization covers node-positive, high-risk early breast cancer as defined in the product information [2].
• Ribociclib may be added to an aromatase inhibitor for three years. The NATALEE trial enrolled patients with stage II or III disease, including node-positive patients and selected node-negative patients with additional risk factors. In the EU, ribociclib is authorized for hormone receptor-positive, HER2-negative early breast cancer at high risk of recurrence [3].
• Advanced disease: For many patients with hormone receptor-positive, HER2-negative advanced or metastatic disease, a CDK4/6 inhibitor combined with endocrine therapy is the usual first-line approach, although this may differ with visceral crisis, rapid progression, or previous CDK4/6 inhibitor treatment. After progression, biomarker-matched options become relevant [4].
• Everolimus: This mTOR inhibitor may be combined with exemestane for selected postmenopausal patients with hormone receptor-positive, HER2-negative advanced disease without symptomatic visceral disease, after progression on a non-steroidal aromatase inhibitor [1].

BRCA-Related Breast Cancer

Inherited (germline) BRCA1 or BRCA2 pathogenic or likely pathogenic variants, often called BRCA mutations, affect how tumor cells repair DNA damage, a vulnerability that PARP inhibitors can exploit.

In Germany, genetic testing for BRCA1/2 is offered based on personal and family history criteria and when the result could affect treatment decisions, such as eligibility for a PARP inhibitor. Genetic counseling is offered alongside testing [1].

For patients with a germline BRCA1/2 pathogenic or likely pathogenic variant and HER2-negative early breast cancer who meet the trial-defined high-risk criteria, one year of adjuvant olaparib after neoadjuvant or adjuvant chemotherapy reduced the risk of recurrence and improved overall survival compared with placebo in the OlympiA trial [5]. High-risk criteria in the trial included:

• After neoadjuvant chemotherapy: residual invasive disease at surgery (no pathological complete response), with a CPS+EG score of 3 or higher also required for hormone receptor-positive disease.
• Triple-negative disease treated with adjuvant chemotherapy: node-positive disease, or node-negative disease with an invasive tumor larger than 2 cm (pT2 or higher).
• Hormone receptor-positive, HER2-negative disease treated with adjuvant chemotherapy: four or more pathologically confirmed positive lymph nodes.

Olaparib and talazoparib are also approved for selected patients with germline BRCA1/2-mutated, HER2-negative locally advanced or metastatic breast cancer. Both generally require prior anthracycline and/or taxane chemotherapy unless these treatments were unsuitable. For hormone receptor-positive disease, prior endocrine therapy is also required unless it is considered unsuitable [4].

Other Biomarker-Matched Treatments

In advanced or metastatic hormone receptor-positive, HER2-negative breast cancer, biomarker testing can help identify additional treatment options:

• ESR1 mutation: For ER-positive, HER2-negative advanced or metastatic disease with an activating ESR1 mutation, elacestrant or imlunestrant may be used after at least one line of endocrine therapy, particularly in patients who previously received and responded to a CDK4/6 inhibitor  [4]. Camizestrant, combined with a CDK4/6 inhibitor, may be used when an ESR1 mutation is detected during first-line endocrine therapy plus a CDK4/6 inhibitor, before disease progression. Etcamah (camizestrant) received an EU-wide marketing authorisation in July 2026 [6]. Premenopausal or perimenopausal patients and men receiving these endocrine therapies may also require ovarian or testicular suppression with an LHRH agonist or antagonist, depending on the specific treatment.
• PIK3CA mutation: For PIK3CA-mutated, ER-positive, HER2-negative advanced or metastatic disease, inavolisib combined with palbociclib and fulvestrant is an option after recurrence during, or within 12 months of completing, adjuvant endocrine therapy. For patients previously treated with a CDK4/6 inhibitor before or after surgery, at least 12 months must have passed between stopping that treatment and recurrence [4].
• PIK3CA, AKT1, or PTEN alteration: For ER-positive, HER2-negative locally advanced or metastatic disease with one or more of these alterations, capivasertib combined with fulvestrant is an option after recurrence or progression on or after an endocrine-based regimen [7].

These biomarker-matched therapies are authorized in the EU for defined patient populations, while other approaches remain investigational. Access may vary by country, eligibility depends on confirming the relevant alteration with an appropriate test, and exact criteria are defined in the product information for each drug.

Hormone and Targeted Therapy Decisions in Breast Cancer

Treatment decisions rarely rest on a single test. Doctors usually weigh the cancer’s receptor and biomarker results alongside several other factors  [1]:

• Hormone receptor and HER2 status
• Disease stage, extent, and recurrence risk based on pathology
• Menopausal status
• Previous treatment and how the cancer responded to it
• Overall health and treatment tolerance
• Inherited genetic findings, where relevant.

Endocrine and targeted drugs are often combined, and the sequence may change as new information emerges. As a result, two patients with the same type of breast cancer may still receive different treatment plans.

Early Breast Cancer and Adjuvant Therapy

In early breast cancer, treatment depends on hormone receptor and HER2 status, recurrence risk, and any inherited genetic findings. Adjuvant endocrine therapy is standard for hormone receptor-positive disease, and selected higher-risk patients may also receive a CDK4/6 inhibitor, or olaparib if they carry a qualifying BRCA1/2 variant [1].

Advanced Breast Cancer and Treatment Sequencing

As advanced hormone receptor-positive, HER2-negative breast cancer progresses, treatment may change according to previous therapy and newly identified biomarkers. Molecular testing can identify ESR1, PIK3CA, AKT1, or PTEN alterations that may open additional treatment options, while chemotherapy remains an option when endocrine-based approaches are no longer suitable [4].

Side Effects and Long-Term Care of Hormone and Targeted Therapy

Hormone and targeted therapies generally cause different side effects from chemotherapy, but they carry real risks that vary by drug, dose, and patient [1]. Monitoring depends on the specific drug and may include blood counts, organ or metabolic function tests, bone density assessment, or heart checks. Drug-specific monitoring is described below.

Side effects are managed through regular monitoring, supportive measures, dose adjustments, or occasionally a change of treatment, to maintain safety and daily functioning.

Managing Hormone Therapy Side Effects

Common effects of endocrine therapy include [1]:

• Hot Flashes and Joint Pain: Hot flashes and joint or muscle discomfort, especially with aromatase inhibitors, are common, along with menstrual changes in premenopausal patients.
• Sexual Health: Non-hormonal moisturizers or lubricants can help with vaginal dryness and discomfort.
• Bone Health: Long-term aromatase inhibitor therapy accelerates bone loss. Bone density monitoring, adequate calcium and vitamin D, and bone-directed drugs (bisphosphonates or denosumab) may be recommended depending on fracture risk.
• Tamoxifen-Specific Risks: Tamoxifen slightly increases the risk of blood clots and uterine changes, rarely including endometrial cancer, so unusual vaginal bleeding should be reported.
• Psychosocial: Patients who notice mood changes or reduced quality of life should discuss supportive options with their oncology team.

Monitoring Targeted Therapy

Targeted therapies require monitoring that reflects how each drug works:

• CDK4/6 inhibitors can lower white blood cell counts, and abemaciclib in particular can cause diarrhea, so blood counts and symptoms are checked regularly. Ribociclib also requires ECG monitoring before treatment and at approximately day 14 of the first cycle, with further ECGs as clinically indicated, together with electrolyte monitoring because it can prolong the QTc interval [2] [3].
• PI3K- and AKT-pathway inhibitors can cause metabolic, gastrointestinal, or skin side effects. Alpelisib is particularly associated with high blood sugar and rash, while capivasertib commonly causes high blood sugar, diarrhea, and rash, so blood glucose and HbA1c are checked before treatment, glucose is monitored closely in the first weeks, and symptoms are managed early [7] [8].
• PARP inhibitors such as olaparib require regular blood count monitoring because they can cause anemia and other low blood counts. Myelodysplastic syndrome and acute myeloid leukemia have also been reported, although uncommonly, including in the OlympiA trial [5].

Doses may be reduced or paused for significant side effects, and new or worsening symptoms should be reported prompt.

Resistance and Progression in Breast Cancer Treatment

Hormone and targeted therapies can lose effectiveness over time through acquired resistance, allowing the cancer to progress. Progression means the current therapy is no longer controlling the cancer. It does not necessarily mean that no further treatment options are available [4]. The oncology team may reassess tumor biology with a tissue biopsy or a blood-based ctDNA test, although a negative blood test does not fully rule out tumor alterations.

Endocrine Therapy Resistance

Resistance to hormone therapy can develop through several mechanisms, including ESR1 mutations that reduce the effectiveness of aromatase inhibitors. Testing for these alterations can help guide the next treatment, which may include another endocrine approach, a biomarker-matched therapy, or chemotherapy [4].

Targeted Therapy Resistance

Cancer cells can also become resistant to targeted therapies, sometimes through new changes in the same pathway the drug was designed to block. Treatment may then be changed according to the new tumor biology, previous therapies, and overall health [4].

Hormone and Targeted Therapy for Breast Cancer in Germany

In Germany, hormone and targeted therapy is planned according to the type of breast cancer, biomarker results, previous treatment, and the patient’s overall clinical situation. The exact treatment and sequence are determined by the treating specialists.

How Does the Hormone and Targeted Therapy Process Work in Germany?

The process usually starts with a review of pathology, hormone receptor and HER2 results, previous treatment, and recent imaging. Additional molecular or genetic testing may be needed to confirm eligibility, followed by specialist or tumor board review and treatment planning. For international patients, German specialists can review records from previous treatment abroad. Drug availability, reimbursement, and treatment costs vary by medicine and indication, so access and expected costs should be clarified before treatment.

TIG GmbH (Treatment in Germany) helps international patients organize medical records and connect with suitable German breast cancer specialists for review and, where appropriate, consultation and treatment planning. The German medical team remains responsible for diagnosis, treatment recommendations, and patient care.

References

1. Leitlinienprogramm Onkologie: S3-Leitlinie Früherkennung, Diagnostik, Therapie und Nachsorge des Mammakarzinoms, Langversion 5.1, Juni 2026 (AWMF-Registernummer 032-045OL).

2. EMA: Verzenios (abemaciclib)  European Public Assessment Report.

3. EMA: Kisqali (ribociclib)  European Public Assessment Report.

4. ESMO Clinical Practice Guideline: Metastatic Breast Cancer, 2026.

5. Geyer CE Jr, et al. Overall survival in the OlympiA phase III trial of adjuvant olaparib in patients with germline pathogenic variants in BRCA1/2 and high-risk, early breast cancer. Annals of Oncology, 2022.

6. EMA: Etcamah (camizestrant) European Public Assessment Report.

7. EMA: Truqap (capivasertib) European Public Assessment Report.

8. EMA: Piqray (alpelisib)  European Public Assessment Report.

9. AOK: Piqray Market Withdrawal in Germany.

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