Radiation Therapy and Ixabepilone in Treating Patients With High-Risk Stage III Prostate Cancer After Surgery

DISEASE CHARACTERISTICS: * Diagnosis of adenocarcinoma of the prostate * Must have undergone any common form of prostatectomy (e.g., open, perineal, laparoscopic, or robotic) within the past 2 years * T3 disease or positive surgical margins * Node negative (N0) and free of distant metastasis (M0) by a bone scan and CT scan or MRI of the pelvis within the past 90 days * Considered high-risk disease * Gleason score = 7 and post-operative PSA \> 0 and ≤ 2 ng/mL OR Gleason score ≥ 8 and post-operative PSA ≥ 0 and ≤ 2 ng/mL * Pre-prostatectomy PSA available * Range of pre-prostatectomy PSA values not required PATIENT CHARACTERISTICS: * Zubrod (ECOG) performance status 0-1 * ANC ≥ 2,000/mm\^3 * Platelet count ≥ 100,000/mm\^3 * Hemoglobin ≥ 8 g/dL * Total bilirubin \< 1.5 times upper limit of normal (ULN) * AST and ALT \< 2.5 times ULN * Alkaline phosphatase \< 2.5 times ULN * Fertile patients must use effective contraception during and for 4 weeks after completion of study therapy * Patients with urinary incontinence waiting for stabilization of urinary function after prostatectomy allowed for up to 6 months * No CTCv4 peripheral neuropathy (motor or sensory) ≥ grade 1 * No history of inflammatory colitis including Crohn disease or ulcerative colitis * No significant history of psychiatric illness * No other invasive malignancy within the past 3 years except adequately treated nonmelanoma skin cancer or carcinoma in situ of the oral cavity * No severe, active co-morbidity with any of the following: * Unstable angina and/or congestive heart failure requiring hospitalization within the past 6 months * Transmural myocardial infarction within the past 6 months * Acute bacterial or fungal infection requiring IV antibiotics * Chronic obstructive pulmonary disease exacerbation or other respiratory illness requiring hospitalization or precluding study therapy within 30 days * Immunocompromised patients or AIDS based upon current CDC definition * HIV testing not required * No history of hypersensitivity reactions to agents containing Cremophor® EL or its derivatives (e.g., polyoxyethylated castor oil) PRIOR CONCURRENT THERAPY: * See Disease Characteristics * No prior pelvic radiotherapy or radiotherapy for another malignancy that encompasses ≥ 30% of major bone marrow-containing areas (e.g., pelvis or lumbar spine) * No prior hormonal therapy for prostate cancer * Prior hormonal agents, e.g., finasteride or dutasteride, for benign prostatic hypertrophy allowed * No other concurrent adjuvant antineoplastic therapy planned while on this protocol, including the following: * Cryotherapy * Hormonal therapy * Other chemotherapy for prostate cancer * Prior chemotherapy for a different type of cancer allowed provided it was administered \> 3 years ago