Study of Dasatinib, Androgen Deprivation Therapy and Radiation

PATIENT ELIGIBILITY -Conditions for Patient Eligibility Each patient must meet all of the following inclusion criteria to be enrolled in the study: * Histologically or pathologically confirmed adenocarcinoma of the prostate to be treated with radiation therapy and hormone therapy. * Intermediate, high or very high risk disease * Intermediate-risk disease (clinical T2b or T2c stage or PSA 10 to 20 ng/mL or Gleason score 7) * High-risk disease (Gleason score 8 to 10, serum PSA \> 20 ng/mL or T3a disease) * Very high-risk disease (T3b or T4) * No prior pelvic or prostate radiation or chemotherapy for prostate cancer. * Clinically negative lymph nodes as established by imaging (pelvic CT or pelvic MR), nodal sampling or dissection within 8 weeks prior to registration. Patients with lymph nodes equivocal or questionable by imaging are eligible if the nodes are \< 1.5 cm. * Bone scan within 12 weeks prior to registration. Equivocal bone scan findings are allowed if plain films are negative for metastasis. * ECOG performance status 0-1 * Age \> 18 * Required entry laboratory parameters within 14 days of study entry: Granulocytes ≥ 1500/µl; platelet count ≥ 100,000/µl; Hgb \> 8.0 g/dl; Creatinine \< 1.5 x the institutional ULN, mg/dl; Bilirubin ≤ 2x institutional upper limit of normal; AST ≤ 2.5 x upper limit of normal, Serum Na+, K+, Mg2+, Phosphate and Calcium within institutional normal range; PT and PTT \< 1.5 ULN * Life expectancy of at least 1 year * No concurrent anticancer therapy. * Peripheral neuropathy must be ≤ Grade 2 * A male subject of fathering potential must use an adequate method of contraception throughout the study \[and for at least 4 weeks after the last dose of study drug\]. * Ability to take oral medication (dasatinib must be swallowed whole) * Signed study-specific consent form prior to study entry Conditions for Patient Ineligibility Patients meeting any of the following exclusion criteria are not to be enrolled in the study: * Evidence of distant metastases (M1). * Prior radical prostatectomy, cryosurgery for prostate cancer, or bilateral orchiectomy for any reason * PSA \> 150 * Pathologically positive lymph nodes or nodes \> 1.5 cm on imaging * Major medical or psychiatric illness which, in the investigator's opinion, would prevent completion of treatment and would interfere with follow-up. * Prior systemic chemotherapy for the study cancer; note that prior chemotherapy for a different cancer is allowable. * Prior radiotherapy, including brachytherapy, to the region of the study cancer that would result in overlap of radiation therapy fields * Medical History and Concurrent Diseases * No malignancy \[other than the one treated in this study\] which required radiotherapy or systemic treatment within the past 5 years. * Concurrent medical condition which may increase the risk of toxicity, including: * Pleural or pericardial effusion of any grade * Cardiac Symptoms; any of the following should be considered for exclusion: * History of significant bleeding disorder unrelated to cancer, including: * No history of pulmonary hypertension