Clinical trial NCT06925984: Stereotactic Radiotherapy for Oligoprogressive ER+/HER- Metastatic Breast Cancer, a Prospective Phase 2 Study (Oligopro-Breast)
Official title: The Oligopro-Breast Study: Stereotactic Radiotherapy for Oligoprogressive ER+/HER- Metastatic Breast Cancer, a Prospective Phase 2 Study
Study type: INTERVENTIONAL
Overall status: NOT_YET_RECRUITING
Phase: NA
Conditions: OligoProgressive Metastatic Disease
Keywords: Oligoprogression
metastatic breast cancer
CDK4/6 inhibitors
SBRT
SABR
radiotherapy
Lead sponsor: Jules Bordet Institute
Sponsor class: OTHER
First posted: 2025-04-13
Enrollment: 48
Sex: FEMALE
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: TREATMENT

Brief summary: The Oligopro-Breast trial is a Phase II study targeting women with ER+/HER2- metastatic breast cancer who have been on endocrine therapy and/or CDK4/6 inhibitors for at least 6 months, and show progressive disease at 1-3 extracranial metastases, which are treatable locally. The trial aims to investigate if treating these resistant metastases with SBRT (or other local treatments if SBRT is not possible) can extend the use of the current systemic therapy.

Patients will continue their existing systemic treatment while receiving SBRT on all progressive lesions. If new oligoprogression occurs, SBRT will be performed again. A new systemic treatment line will start if there is polyprogression (more than 3 lesions at once), progression of more than 6 lesions over 12 months, intracranial progression, or lesions that cannot be treated locally.

The scientific question is whether local treatment of resistant metastases can prolong the effectiveness of ongoing systemic therapy, which is particularly beneficial if the treatment is well-tolerated. The primary objective is to measure the proportion of patients surviving without changing their systemic treatment line at 6 months after SBRT.

This trial is significant for patients as it explores a method to potentially extend the duration of effective and well-tolerated treatments, offering hope for better management of metastatic breast cancer.


Eligibility criteria: Inclusion Criteria:

* ECOG performance status 0-2.
* Histologically confirmed ER+/HER2- MBC.
* History of polymetastatic disease. Patients with genuine oligometastatic disease and 1-3 oligoprogressive lesions are only allowed if ablative therapy of all metastases is deemed impossible.
* Under 1st to 2nd systemic treatment line with hormonotherapy and/or CDK4/6 inhibitors for at least 6 months before progression.
* Progressive disease at 1-3 extracranial sites.
* Ability to treat all progressive lesions locally according to the treating radiation oncologist.

Exclusion Criteria:

* Second malignancy if it is not in complete remission.
* Previous local treatment for oligoprogression under the current systemic treatment line
* Current progression in a lesion that has been treated with SBRT before and is not amendable for surgery or radiofrequency ablation (RFA).
* Progressive or newly diagnosed brain metastases. Known brain metastases that have been nonprogressive for at least 6 months, are not an exclusion criterion.
* Inability to continue the same ST line after local therapy (for example because of toxicity or patient refusal).
* Pregnancy.
* Inability to sign the informed consent.

Primary outcomes:
measure: NExt Systemic Treatment-Free Survival (NEST-FS)
timeFrame: At 6 months
Secondary outcomes:
measure: Time to next line of systemic therapy (NEST)
timeFrame: 3 years
measure: Progression-free survival (PFS)
timeFrame: 3 years
measure: Modified Progression-free survival (mPFS)
timeFrame: 3 years
measure: Chemotherapy-free survival
timeFrame: 3 years
measure: Progression-free survival after start of the subsequent line of systemic treatment (PFS2)
timeFrame: 3 year
measure: Patterns of metastatic progression
timeFrame: 3 years
measure: Overall survival (OS)
timeFrame: 3 years
measure: Acute and late physician-scored toxicity of the local intervention
timeFrame: 3 years
measure: Quality of life (QoL)
timeFrame: 3 years
Other outcomes:
measure: Correlation between (1) ctDNA burden at baseline and (2) ctDNA burden 10-12 weeks after SBRT versus the modified progression-free-survival (mPFS). NEST-FS in function of ESR1 status.
timeFrame: 3 years
Locations:
city: Brussels
country: Belgium
facility: Jules Bordet Institute
city: Ghent
country: Belgium
facility: UZ Gent
city: Kortrijk
country: Belgium
facility: AZ Groeninge
city: Mechelen
country: Belgium
facility: AZ Sint-Maarten
city: Namur
country: Belgium
facility: CHU UCL Namur - Site Saint Elisabeth
Study officials:
References: