Whole Brain Radiation Using IMRT for Patients With Brain Metastases

Single Center, Phase II Study of Whole Brain Radiation Using IMRT to Spare the Hippocampus While Delivering Differential Doses to Subclinical Sites Versus Gross Disease for Treatment of Patients With Brain Metastases

Some cancers can spread, or metastasize, to the brain. When they do, treatment often involves surgery and/or radiation. Optimal treatment of brain metastases would maximize disease control and minimize toxicity (or side effects), and improve the quality of life of patients. A common type of radiation used for brain metastases is called whole brain radiation, which treats not just the cancer that can be seen on scans (i.e., gross disease), but the smaller sites of cancer that may not be visible (i.e. subclinical disease). Fractionation is used to describe repetitive treatments in which small doses (fractions) of a total planned dose are given at separate clinic visits. The most common dosing regimen is 30 Gray (Gy), using 3 Gy per fraction over 10 fractions. Previous studies have suggested that using intensity modulated radiation therapy (IMRT) may be a safer way to deliver higher doses to gross disease and lower doses to the rest of the brain that may contain subclinical disease. This approach may spare the rest of the brain from radiation complications and side effects.

The goal of this study is to determine whether using IMRT to treat brain metastases is more effective than current standard whole brain radiation in controlling gross disease and whether patient quality of life and hair loss is improved compared to previous studies using whole brain radiation.

This phase II clinical trial will utilize intensity modulated whole brain radiation therapy in order to deliver a smaller, yet effective dose for subclinical disease while giving a higher dose to gross disease for patients with more than one brain metastasis. In this study, a dose of 30 Gray (Gy) will be prescribed to subclinical sites and 60 or 45 Gy to visible brain metastases.

There is evidence from previous studies (including Radiation Therapy Oncology Group (RTOG) 0933) that hippocampal avoidance during whole brain radiotherapy using IMRT may decrease toxicity in the form of memory loss. Patients who had brain metastases within the region of hippocampal avoidance were not eligible for enrollment on RTOG 0933. In contrast, this study will include this group of patients since IMRT will be used to not only deliver higher doses to visible brain metastases even though they are located within the hippocampal avoidance region, but also to avoid the hippocampus itself. This approach may help to preserve memory function. Additionally, while temporary (and sometimes permanent) alopecia results from conventional whole brain radiation, IMRT spares the skin and possibly decreases the rate of hair loss. Dose to the scalp will be limited to as low as possible in order to decrease the risk of permanent alopecia in this study.

Inclusion Criteria:

• Pathologically proven diagnosis of a non-hematopoietic malignancy other than small cell lung cancer and germ cell malignancy within 5 years of registration. Patients with metastasis of unknown primary tumor are permitted.
• History/physical examination within 30 days prior to registration.
• Age ≥ 18 years
• Karnofsky performance status ≥ 70
• Ability to understand and the willingness to sign a written informed consent document.
• Women of child-bearing potential must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry, 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.
• Women of childbearing potential must have a negative qualitative serum pregnancy test ≤ 2 weeks prior to study entry. A female of child-bearing potential is any woman (regardless of sexual orientation, having undergone a tubal ligation, or remaining celibate by choice) who meets the following criteria: 1) Has not undergone a hysterectomy or bilateral oophorectomy; or 2) 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).
• More than one brain metastasis (qualifying measurable brain lesions are any contrast enhancing metastases identifiable by the physician).
• Patients who have undergone a resection for brain metastases will be eligible for participation if they have any residual metastases present on post operative MRI of the brain.

Exclusion Criteria:

• Patients with leptomeningeal metastases
• Plan for chemotherapy or targeted therapies during whole brain radiation or within 1 week of completing radiation therapy
• Contraindication to Magnetic Resonance (MR) imaging
• Serum creatinine > 1.4 mg/dl ≤ 30 days prior to study entry
• Prior radiation therapy to the brain besides radiosurgery
• Severe active comorbidities which would make the patient an unacceptable candidate for this clinical trial per physician discretion
• Patients with brain metastases involving the brainstem or chiasm
• Non English speaking patients