HR-positive, HER2-negative breast cancer, stage I-II

HR-positive / HER2-negative breast cancer →

Surgery first, a genomic test to decide whether chemotherapy adds anything, a few weeks of radiotherapy, then five to ten years of endocrine tablets, with a CDK4/6 inhibitor for two or three years if the risk is high.

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Typical sequence for stage I-II (early) disease; durations are protocol values (cycle counts and lengths, fraction schedules, guideline follow-up intervals), not averages of real patients. Your team's plan will differ in detail.

Phase by phase

1. Diagnosis
weeks 0-4
Core biopsy with ER, PR, HER2 and Ki-67; mammography and ultrasound, MRI when needed.
Histopathology & immunohistochemistry Mammography & tomosynthesis
Source
2. Surgery
weeks 2-4
Breast-conserving surgery or mastectomy with sentinel node biopsy; recovery 2-4 weeks.
Sentinel lymph node biopsy
Source
3. Genomic assay decision
weeks 3-6
A 21-gene recurrence score (or similar) on the tumour: in TAILORx, women over 50 with node-negative disease and a score of 11-25 gained nothing from chemotherapy.
Companion diagnostics
Source
Decision: Does the genomic score and stage justify chemotherapy?
- Low or intermediate score: skip chemotherapy, go to radiotherapy and endocrine therapy
- High score, or young with an intermediate score, or four or more nodes: chemotherapy first
4. Chemotherapy (high genomic risk only)
weeks 5-23
Four to six cycles of a taxane-based or anthracycline-taxane regimen, only when the assay or stage shows a high recurrence risk.
DocetaxelCyclophosphamideCytotoxic chemotherapy
Source
5. Radiotherapy
weeks 17-22
After breast conservation: 26 Gy in 5 fractions over one week (FAST-Forward) or 40 Gy in 15 fractions over 3 weeks; longer courses with a boost in some settings.
IMRT / IGRT (modern external beam)
Source
6. Endocrine therapy
from week 18, continues for years
Tamoxifen or an aromatase inhibitor (with ovarian suppression before menopause) for 5 years, extended to 10 in higher-risk disease.
TamoxifenLetrozole (and other aromatase inhibitors)Endocrine therapy (SERMs, AIs, SERDs)
Source
Decision: Is the recurrence risk high enough for a CDK4/6 inhibitor?
- Node-negative, small tumour: endocrine therapy alone
- Node-positive or high-risk features: add abemaciclib (2 years) or ribociclib (3 years)
7. CDK4/6 inhibitor (high-risk node-positive)
weeks 18-174 (alongside the previous phase)
Abemaciclib for 2 years (monarchE) or ribociclib for 3 years (NATALEE) alongside endocrine therapy in higher-risk disease.
AbemaciclibRibociclibCDK4/6 inhibitors
Source
8. Surveillance
from week 278, continues for years
Clinic visits every 3-6 months for 3 years then yearly, with annual mammography; bone density monitoring on aromatase inhibitors.
Source

Sources

Phase by phase

1. Diagnosis

weeks 0-4

Core biopsy with ER, PR, HER2 and Ki-67; mammography and ultrasound, MRI when needed.

Histopathology & immunohistochemistry Mammography & tomosynthesis

Source

2. Surgery

weeks 2-4

Breast-conserving surgery or mastectomy with sentinel node biopsy; recovery 2-4 weeks.

Sentinel lymph node biopsy

Source

3. Genomic assay decision

weeks 3-6

A 21-gene recurrence score (or similar) on the tumour: in TAILORx, women over 50 with node-negative disease and a score of 11-25 gained nothing from chemotherapy.

Companion diagnostics

Source

Decision: Does the genomic score and stage justify chemotherapy?

Low or intermediate score: skip chemotherapy, go to radiotherapy and endocrine therapy
High score, or young with an intermediate score, or four or more nodes: chemotherapy first

4. Chemotherapy (high genomic risk only)

weeks 5-23

Four to six cycles of a taxane-based or anthracycline-taxane regimen, only when the assay or stage shows a high recurrence risk.

DocetaxelCyclophosphamideCytotoxic chemotherapy

Source

5. Radiotherapy

weeks 17-22

After breast conservation: 26 Gy in 5 fractions over one week (FAST-Forward) or 40 Gy in 15 fractions over 3 weeks; longer courses with a boost in some settings.

IMRT / IGRT (modern external beam)

Source

6. Endocrine therapy

from week 18, continues for years

Tamoxifen or an aromatase inhibitor (with ovarian suppression before menopause) for 5 years, extended to 10 in higher-risk disease.

TamoxifenLetrozole (and other aromatase inhibitors)Endocrine therapy (SERMs, AIs, SERDs)

Source

Decision: Is the recurrence risk high enough for a CDK4/6 inhibitor?

Node-negative, small tumour: endocrine therapy alone
Node-positive or high-risk features: add abemaciclib (2 years) or ribociclib (3 years)

7. CDK4/6 inhibitor (high-risk node-positive)

weeks 18-174 (alongside the previous phase)

Abemaciclib for 2 years (monarchE) or ribociclib for 3 years (NATALEE) alongside endocrine therapy in higher-risk disease.

AbemaciclibRibociclibCDK4/6 inhibitors

Source

8. Surveillance

from week 278, continues for years

Clinic visits every 3-6 months for 3 years then yearly, with annual mammography; bone density monitoring on aromatase inhibitors.

Source