This study with Chair-Based, Gantry-less Proton System (CBGS) (aka P-CURE Proton Beam Therapy System or Fixed Beam Chair-based Delivery System) is composed of 3 arms, as following:

ARM1: Patients with locally recurrent, previously irradiated thoracic cancer indicated for re- irradiation.

ARM2: Patients with recurrent Head and Neck, Brain and Spinal Cord tumors, indicated for re- irradiation.

ARM3: Patients with unresectable pancreatic cancer.

The primary objectives of the study for all arms are: 1. to describe the efficacy (local control after 3 month) and acute toxicity for patients treated with a fully-integrated CBGS and (2) to compare treatment plans between the fully-integrated CBGS and Photon therapy defined for each patient, based upon OAR sparing for comparable target coverage.

Inclusion Criteria:

• Pathologically (histologically or cytologically) proven malignancy
• Treatment planning analysis shows advantage to proton over photon treatments
• both malignancies (such as thoracic tumors) as well as metastatic lesions (such as metastatic breast cancer or colorectal cancer to the lungs) are allowed
• Patient must have CT confirmation of the tumor
• Patients must have a life expectancy of > 6 months
• Patients must have measurable disease to be treated with proton radiation (minimum tumor dimension at least 10 mm on CT imaging).
• Patients must be a candidate for definitive radiation dose
• There are no limits on prior therapy. Patients are allowed to have prior chemotherapy and surgery. Patients are allowed to have concurrent chemotherapy with radiation treatment. Patients are allowed to have chemotherapy or surgery after radiation treatment

Exclusion Criteria:

1. Severe, active co-morbidity, defined as follows:

   1. Unstable angina and/or congestive heart failure requiring hospitalization within the last 6 months
   2. Transmural myocardial infarction within the last 6 months
   3. Chronic obstructive pulmonary disease exacerbation or other respiratory illness other than the diagnosed lung cancer requiring hospitalization or precluding study therapy within 30 days before registration
   4. Acquired immune deficiency syndrome (AIDS) based upon current CDC definition (protocol may be significantly immunosuppressive endangering AIDS patients)

2. Pregnancy or women of childbearing potential and men who are sexually active and not willing/able to use medically acceptable forms of contraception

3. Patients with life expectancy < 6 months

4. Patients that participate in another, active clinical trial carried out concurrently with this protocol