Personalized PULSAR MRI-guided radiation for central lung tumors

Feasibility Study of Personalized Ultra-fractionated Stereotactic Ablative Radiotherapy (PULSAR) for Cancers of the Central Lung

This will test whether personalized, MRI-guided PULSAR radiation given as five widely spaced high-precision doses can safely treat small central primary or metastatic lung tumors.

Quick facts

• Phase: Early Phase 1
• Study type: Interventional
• Enrollment: 30 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: University of Texas Southwestern Medical Center (Academic / other)
• Drugs / interventions: radiation
• Locations: 1 site (Dallas, Texas)
• Trial ID: NCT06712745 on ClinicalTrials.gov

What this trial studies

This single-arm, early-phase effort uses a 1.5T MR-guided linear accelerator (Unity, Elekta) with real-time motion monitoring to deliver personalized ultra-fractionated stereotactic ablative radiotherapy (PULSAR) to central lung tumors. Patients receive five high-precision fractions delivered one at a time every three weeks with MRI-guided adaptive planning before each session. The protocol aims to improve tumor visualization, reduce planning and motion margins, and permit normal tissue healing between widely spaced fractions to lower toxicity risk for ultra-central lesions. Eligible tumors are 1.5–5 cm and located within the central 2 cm zone or within 1 cm of the mediastinum, esophagus, or proximal bronchial tree, and patients must be able to tolerate MRI and have ECOG/Zubrod 0–2.

Who should consider this trial

Good fit: Adults (≥18) with histologically confirmed cancer and a 1.5–5 cm primary or metastatic lung lesion located in the central zone (within 2 cm centrally or within 1 cm of mediastinum, esophagus, or proximal bronchial tree), ECOG 0–2, and able to undergo MRI are ideal candidates.

Not a fit: Patients with tumors larger than 5 cm, tumors outside the defined central zone, those who cannot tolerate MRI, have poor performance status, or who are pregnant are unlikely to benefit from this protocol.

Why it matters

Potential benefit: If successful, this approach could reduce radiation damage to nearby critical structures while keeping effective tumor control, making treatment safer for ultra-central lung tumors.

How similar studies have performed: MR-guided adaptive SABR and spacing of fractions have shown promising precision and safety in early reports, but personalized PULSAR ultrafractionation for ultra-central lung tumors remains novel and not yet widely validated.

Eligibility criteria

Inclusion Criteria:

1. Age ≥ 18 years of age.
2. Histologically proven diagnosis of cancer. At a minimum, the lung tumor in consideration for treatment must be clinically judged as related to the biopsied site.
3. Stage: Tumor (ITV) 1.5 - 5 cm in maximum diameter.
4. Tumor entirely within the 2 cm "central zone" or within 1 cm of the mediastinum, esophagus or proximal bronchial tree by investigator assessment.
5. Zubrod/ECOG Performance Status 0-2 within 30 days prior to registration.
6. Ability to tolerate MRI.
7. All men, as well as women of child-bearing potential\* must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) from the time of consent, for the duration of study participation, and for 90 days following completion of therapy. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately.

Note: A female of child-bearing potential is any woman (regardless of sexual orientation, marital status, having undergone a tubal ligation, or remaining celibate by choice) who meets the following criteria:

* Has not undergone a hysterectomy or bilateral oophorectomy; or
* Has not been naturally postmenopausal for at least 12 consecutive months (i.e., has had menses at any time in the preceding 12 consecutive months).

Exclusion Criteria:

1. Prior radiotherapy to the region of the study cancer that would result in overlap of radiation therapy fields.
2. Plans for the patient to receive other local therapy in lung (including standard fractionated radiotherapy and/or surgery) while on this study, except at disease progression.
3. Females of reproductive potential who are not using an effective method of birth control and females who are pregnant or breastfeeding or have a positive (urine or serum) pregnancy test prior to study entry.
4. Prior administration of anti-VEGF (vascular endothelial growth factor) therapy within 1 year.

Where this trial is running

Dallas, Texas

• University of Texas Southwestern Medical Center — Dallas, Texas, United States (Recruiting)

Study contacts

• Principal investigator: KENNETH WESTOVER, MD, PhD — University of Texas Southwestern Medical Center
• Study coordinator: Sarah Neufeld, Ms, Mba

Conditions Cancer, Lung; Metastasis; lung; central lumg; cancer; metastasis; PULSAR; non small cell lung cancer