Blood Test to Predict Radiation Response and Toxicity in Patients Undergoing Radiation Therapy

Exploratory study to collect paired pre- and post-irradiation blood samples from 150
participants.

Inclusion Criteria:

1. Male and female patients age 18 or older

2. Diagnosed with a primary rectal or esophageal cancer

3. Planned radiation therapy to the esophagogastric area to a minimum of 4140 cGy for
esophageal/gastroesophageal junction cancer or to pelvis to a minimum of 4500 cGy for
rectal cancer as part of clinical care

4. Combining chemotherapy is allowed

5. ECOG Performance Status 0-2

6. Able to provide written informed consent

Exclusion Criteria:

1. Subjects who have received radiation within three (3) months to esophagogastric or
pelvic areas prior to consent

2. Subjects, who in the opinion of the investigator, may not be able to comply with the
requirements of the study