Treatment: Radiation (Chemotherapy may be given after RT at Physician's discretion. Planned resection is ok for patients with primary esophageal, lung, and rectal cancer.

Inclusion and Exclusion Criteria: - Patients with primary esophageal, lung, and rectal carcinoma who are to be treated with neo-adjuvant chemoradiotherapy before a planned resection. - Patients with primary, local, or regional carcinoma of the head/neck, lung, esophagus, or cervix receiving definitive therapy. - Patients with clinically localized prostate cancer being treated with definitive external beam radiotherapy; brachytherapy may be delivered AFTER external beam radiotherapy - Prior and concurrent hormone therapy is allowed - No prior chemo or RT w/in 6 months of enrollment

The purpose of this study is to investigate specific proteins in the blood of and their response to ionizing radiation. This information will be used to aid in understanding and predicting individual responses to radiation therapy that may allow for more personalized dosing of radiation therapy, with the goal of reducing side effects and improving cure rates.

Treatment: Radiation (Chemotherapy may be given after RT at Physician's discretion. Planned resection is ok for patients with primary esophageal, lung, and rectal cancer.