SOLIS: Single-Dose Radiotherapy With Omission of Lumpectomy for Intact Small Breast Cancers

NCT07844759 | Not Yet Recruiting

• 1 other identifier: RAD 2024
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

SOLIS is a prospective, single-arm, single-institution pilot trial evaluating single-fraction stereotactic radiotherapy (24 Gy to the planning target volume with a simultaneous integrated boost of 30 Gy to the clinical target volume) delivered with a cleared linear accelerator as definitive non-operative local treatment for early-stage, hormone receptor-positive, HER2-negative breast cancer with planned omission of lumpectomy. Adjuvant endocrine therapy is prescribed on-label. The primary endpoint is the incidence of CTCAE v5.0 Grade ≥2 skin adverse events within 90 days of treatment, monitored with a pre-specified Bayesian safety stopping rule. Secondary endpoints include biopsy-confirmed absence of residual invasive carcinoma at 12 months, imaging response on multiparametric MRI and FDG PET/CT, late toxicity, cosmesis, patient-reported outcomes, salvage surgery, and disease control through 36 months.

Conditions

Breast Cancer; Early-Stage Breast Carcinoma; Hormone Receptor-Positive Breast Cancer; HER2-Negative Breast Cancer

Keywords

SOLIS; single-fraction SDRT; stereotactic radiosurgery; lumpectomy omission; non-operative; HR-positive; HER2-negative

Outcome Measures

Primary Outcomes (1)

• Incidence of CTCAE v5.0 Grade ≥2 skin adverse events

  Proportion of treated patients with at least one Grade ≥2 skin AE within 90 days, graded per protocol by study research nurse practitioner.

  90 days after SDRT

Secondary Outcomes (7)

• Absence of residual invasive carcinoma on protocol-mandated tissue sampling

  12 months

• Modified RECIST 1.1 response on multiparametric breast MRI

  Up to 36 months

• PERCIST 1.0 metabolic response on FDG PET/CT

  6 and 12 months

• Late Grade ≥2 skin adverse events

  From 90 days through 36 months

• Rate of salvage surgery

  Through 36 months

Study Arms (1)

Single-fraction SDRT plus adjuvant endocrine therapy

EXPERIMENTAL

Single-fraction SDRT plus adjuvant endocrine therapy.

Radiation: Stereotactic Radiation Therapy; Drug: Endocrine Therapy

Interventions

Stereotactic Radiation Therapy RADIATION

Single fraction 24 Gy to PTV with SIB 30 Gy to CTV on Varian Edge with image guidance.

Single-fraction SDRT plus adjuvant endocrine therapy

Endocrine Therapy DRUG

Adjuvant aromatase inhibitor or tamoxifen initiated within 30 days of SDRT; on-label; recommended 5 years.

Single-fraction SDRT plus adjuvant endocrine therapy

Eligibility Criteria

• Age: 50 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Invasive ductal carcinoma or favorable special histology confirmed by core biopsy.
• Unifocal tumor ≤2 cm; estrogen receptor-positive and HER2-negative; grade 1-2; clinically node-negative (cN0).
• Age ≥65, or age 50-64 when surgery is unsuitable or declined (capped at 10 of 30 participants).
• Tumor ≥5 mm from skin and pectoralis; willing to receive adjuvant endocrine therapy.
• Zubrod performance status 0-2; able to undergo MRI and FDG PET/CT; informed consent.

You may not qualify if:

• Multifocal or multicentric disease; pure DCIS; invasive lobular carcinoma \>10%; extensive intraductal component or diffuse calcifications.
• Grade 3, triple-negative, or HER2-positive disease; nodal or distant metastases.
• Prior ipsilateral breast radiation or excisional biopsy/lumpectomy; neoadjuvant chemotherapy.
• Tumor \<5 mm from skin or pectoralis; inability to meet dose constraints or PTV \>60 cm³.
• Connective tissue disease; prohibited other malignancy; pregnancy or lactation.
• Pathogenic BRCA1, BRCA2, PALB2, or TP53 variant; investigator judgment that participation is inappropriate.

Sponsors & Collaborators

• Renaissance Institute of Precision Oncology and Radiosurgery: lead

Study Sites (1)

Renaissance Institute for Precision Oncology & Radiosurgery

Winter Park, Florida, 32789, United States

Location

MeSH Terms

Conditions

Breast Neoplasms

Interventions

Radiosurgery

Condition Hierarchy (Ancestors)

Neoplasms by Site; Neoplasms; Breast Diseases; Skin Diseases; Skin and Connective Tissue Diseases

Intervention Hierarchy (Ancestors)

Radiotherapy; Therapeutics; Stereotaxic Techniques; Neurosurgical Procedures; Surgical Procedures, Operative; Investigative Techniques

Central Study Contacts

Julia Pierson

CONTACT

321-972-1102; jpierson@therenaissanceinstitute.org

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Study Record Dates

• First Submitted: September 21, 2026
• First Posted: September 28, 2026
• Study Start (Estimated): January 1, 2027
• Primary Completion (Estimated): January 1, 2029
• Study Completion (Estimated): January 1, 2032
• Last Updated: September 28, 2026

Record last verified: 2026-09

Locations

US (1)