Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed adenocarcinoma of the prostate

- Prostate-specific antigen (PSA)-only progression despite androgen deprivation
therapy, defined as 3 rising PSA levels with an interval of ≥ 2 weeks between each
determination AND the most recent PSA level ≥ 1 ng/mL within the past 2 weeks

- Patients with a second or third confirmatory PSA value less than the previous
value are eligible provided a fourth PSA value is greater than all prior values

- A withdrawl period (4 weeks for flutamide and 6 weeks for bicalutamide or
nilutamide) is required to document PSA progression for patients who have been
on antiandrogen therapy within the past 4 weeks

- No known CNS disease

- No evidence of metastatic disease by standard imaging (i.e., bone scan, chest x-ray
or chest CT scan, and CT scan or MRI of the abdomen and pelvis)

- No known brain metastases

PATIENT CHARACTERISTICS:

- ECOG performance status 0-1

- Life expectancy ≥ 6 months

- Fertile patients must use effective contraception

- No proteinuria, defined by 1 of the following:

- Urine protein:creatinine ratio < 1.0

- Proteinuria < 2+ by dipstick urinalysis

- Proteinuria ≤ 1 g by 24-hour urine collection (for patients with proteinuria ≥
2+ by dipstick urinalysis)

- No other uncontrolled illness, including, but not limited to, any of the following:

- Ongoing or active infection

- Symptomatic congestive heart failure

- Unstable angina pectoris

- Cardiac arrhythmia

- Psychiatric or social situation that would preclude study compliance

- No uncontrolled hypertension, defined as systolic blood pressure (BP) > 150 mm Hg
and/or diastolic BP > 100 mm Hg on antihypertensive medication

- No history of hypertensive crisis or hypertensive encephalopathy

- No New York Heart Association class II-IV congestive heart failure

- No myocardial infarction or unstable angina within the past 12 months

- No stroke or transient ischemic attack within the past 6 months

- No abdominal fistula, gastrointestinal perforation, or intra-abdominal abscess within
the past 6 months

- No significant traumatic injury within the past 28 days

- No significant vascular disease (i.e., aortic aneurysm or aortic dissection)

- No symptomatic peripheral vascular disease

- No evidence of bleeding diathesis or coagulopathy

- No serious nonhealing wound, ulcer, or bone fracture

- No hypersensitivity to any component of bevacizumab

- No history of allergic reactions attributed to compounds of similar chemical or
biological composition to bevacizumab

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- At least 1 week since prior core biopsy or other minor surgical procedure (excluding
placement of a vascular access device)

- At least 4 weeks since prior major surgical procedure or open biopsy

- At least 4 weeks since prior systemic therapy except for luteinizing
hormone-releasing hormone (LHRH) analogue therapy or steroids

- Patients receiving LHRH agonist therapy must continue LHRH agonist therapy
during study participation

- Steroids used for treatment of prostate cancer should be discontinued prior to
starting bevacizumab

- No prior bevacizumab

- No concurrent major surgical procedure

- No concurrent antiretroviral therapy for patients with immune deficiencies, such as
HIV

- No other concurrent investigational or commercial agents or therapies (except LHRH
agonists) for this malignancy

- Concurrent anticoagulants allowed provided patient has been on therapy for at least 4
weeks and has no acute thromboembolic activity