Salvage Radiation Therapy and Taxotere for PSA Failure After Radical Prostatectomy

Inclusion Criteria: * Age ≥ 18 * Performance Status: Karnofsky performance status ≥ 80% (Performance status is an attempt to quantify cancer patients' general well-being and activities of daily life. The Karnofsky score runs from 100 to 0, where 100 is "perfect" health and 0 is death.) * Has undergone prostatectomy for histologically confirmed adenocarcinoma of the prostate at least 6 weeks prior to registration. (If prostatectomy was completed at an outside facility, a University of Michigan pathology review must take place to confirm adenocarcinoma.) * Has biochemical evidence of failure as determined by at least two PSA measurements after prostatectomy. This must be demonstrated by an increase of at least 0.1 ng/mL between two consecutive measurements, both obtained after prostatectomy. The most recent measurement (within 28 days of registration) must be 0.3 ng/mL or greater. * Has undergone pelvic CT (Computerized Tomography) scan and radionuclide bone scan within 90 days prior to registration that showed no evidence of regional or distant nodal or bone metastasis. * Patients with pelvic or abdominal lymph nodes equivocal or questionable by imaging are eligible if the nodes are \< 1.5 cm in long axis. * Equivocal bone scan findings are allowed if plain films show no conclusive evidence of metastasis. * Hematologic Criteria: CBC (Complete Blood Count)/differential obtained within 28 days prior to registration on study, with adequate bone marrow function defined as follows: * Absolute neutrophil count (ANC) ≥ 1,500 cells/mm3 * Platelets ≥ 100,000 cells/mm3 * Hemoglobin ≥ 8.0 g/dl (Note: The use of transfusion or other intervention to achieve Hgb = 8.0 g/dl is acceptable). * Hepatic Criteria within 28 days prior to registration: * Total bilirubin \< 1 x institutional upper limit of normal (ULN) * ALT (Alanine Transaminase), AST (Aspartate Aminotransferase), and alkaline phosphatase must be within the eligible ranges stipulated in protocol table * Serum creatinine \< 2 x ULN * Both radiation oncology and medical oncology consultation prior to registration. * Pharmacologic androgen ablation for prostate cancer will be allowed only if given prior to prostatectomy. * Patient must sign study specific informed consent prior to study entry. * Peripheral neuropathy: must be ≤ grade 1 * Patients must be willing to consent to using effective contraception while on treatment and for at least 3 months thereafter. Exclusion Criteria: * Patients with a history of severe hypersensitivity reaction to docetaxel or other drugs formulated with polysorbate 80. * Evidence of M1 metastatic disease * Pathologically positive lymph nodes or nodes \> 1.5 cm on imaging * Prior pelvic radiotherapy that would result in overlap of radiation therapy fields or systemic cytotoxic chemotherapy. * Prior invasive malignancy (except non-melanomatous skin cancer) unless disease free for a minimum of 5 years (for example,carcinoma in situ of the oral cavity or bladder are permissible) * Severe, active co-morbidity, defined as follows, active co-morbidity, defined as follows: * Unstable angina and/or congestive heart failure requiring hospitalization within the 6 months prior to registration. * Transmural myocardial infarction within the 6 months prior to registration * Acute bacterial or fungal infection requiring intravenous antibiotics at the time of registration * Acquired Immune Deficiency Syndrome (AIDS) based upon current CDC definition; note, however, that HIV testing is not required for entry into this protocol. The need to exclude patients with AIDS from this protocol is necessary because the treatments involved in this protocol may be significantly immunosuppressive.