Can a simple blood test predict radiation success in rare spine tumors?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Age ≥18 years * Histologically proven chordoma of the skull base, spine, or sacrum (coccyx lesions are eligible). * Radiographic evidence of spinal sacral chordoma is required and may be obtained from computed tomography imaging and/or magnetic resonance imaging. Other studies may be used with principal investigator approval. Note: Patients enrolled in Dr. Chetan Bettegowda's J1576 study, (IRB00075499) may be considered eligible for this trial. The J1576 study enrolls patients who have been diagnosed with Chordoma. Prior to enrollment, all patients must be consented specifically for participation in this Chordoma study (IRB00291203). * Treating physician must deem that neoadjuvant proton therapy or SBRT is appropriate treatment for the chordoma. * Surgical resection with curative intent must be planned. * The patient must have a Karnofsky Performance Score of 40 or greater. * If a woman is of child-bearing potential, a negative urine or serum pregnancy test must be demonstrated prior to treatment. Women of childbearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) for the duration of study participation and for up to 12 weeks following the study. Should a woman become pregnant or suspect she is pregnant while participating in this study she should inform her treating physician immediately. * Ability to understand and the willingness to sign a written informed consent document. Exclusion Criteria: * Prior radiation or radiosurgery to the involved level of the spine. * Patients with metastatic disease will be excluded. * Prior malignancies are excluded except for adequately treated basal cell or squamous cell skin cancer, cervical carcinoma in situ, or other cancer from which the patient has been disease free for at least 1 year. * Patients with uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements will be excluded. * Pregnant women are excluded. Women of child-bearing potential who are unwilling or unable to use and acceptable method of birth control to avoid pregnancy for the entire study period and up to 12 weeks after the study are excluded. Male subjects must also agree to use effective contraception for the same period as above.