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

This will be achieved by demonstrating the feasibility of applying adaptive radiation therapy given in PULSAR fractionation and using a 1.5T MR-guided linac system with real-time motion monitoring (Unity, Elekta). The hypothesis is that safety can be improved through: (1) better visualization of tumors, leading to less uncertainty when delineating GTVs; (2) reduced margins for setup, motion, or other sources of uncertainty; and (3) improved normal tissue healing between radiation fractions. To achieve this, we propose a personalized ultrafractionated stereotactic adaptive radiotherapy (PULSAR) delivery schedule, administering 5 fractions total, given as one fraction every 3 weeks (Fig. 3) and using MRI-guided adaptive treatment planning.

This study is single arm in nature and in the feasibility phase

Inclusion criteria

• Age ≥ 18 years of age.
• 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.
• Stage: Tumor (ITV) 1.5 - 5 cm in maximum diameter.
• Tumor entirely within the 2 cm "central zone" or within 1 cm of the mediastinum, esophagus or proximal bronchial tree by investigator assessment.
• Zubrod/ECOG Performance Status 0-2 within 30 days prior to registration.
• Ability to tolerate MRI.
• 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

• Prior radiotherapy to the region of the study cancer that would result in overlap of radiation therapy fields.
• 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.
• 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.
• Prior administration of anti-VEGF (vascular endothelial growth factor) therapy within 1 year.