Intensity-Modulated Radiation Therapy in Treating Patients Undergoing Androgen Deprivation Therapy for Metastatic Prostate Cancer

OBJECTIVES:

- To evaluate the time to PSA relapse in patients with oligometastatic (i.e., ≤ 5 lesions)
hormone-sensitive prostate cancer treated with 36 weeks of androgen deprivation therapy
and localized radiotherapy to all known tumor sites.

- To assess the PSA and objective tumor response rate in patients treated with this
regimen.

- To assess the toxicity of this regimen in these patients.

- To evaluate the feasibility and toxicities of using helical tomotherapy image-guided
intensity-modulated radiotherapy to treat oligometastatic sites in these patients.

OUTLINE: Patients are stratified according to androgen-deprivation therapy status at time of
study entry (currently receiving or planning to receive vs completed or almost completed).

Patients who are not currently androgen deprivation therapy at the time of enrollment receive
36 weeks of androgen deprivation therapy comprising goserelin subcutaneously or leuprolide
acetate intramuscularly once every 4-12 weeks and oral bicalutamide once daily for 36 weeks.
Patients who are already receiving androgen deprivation therapy at the time of enrollment
will continue treatment until they have received a total of 36 weeks of therapy.

All patients undergo helical tomotherapy image-guided intensity-modulated radiotherapy
beginning at the time they achieve PSA normalization (i.e., stable or declining PSA level ≤ 4
ng/mL or stable or declining PSA level ≤ pretreatment level, whichever is smaller) on two
consecutive measurements taken after androgen deprivation therapy is initiated. All known
metastatic sites are irradiated for 2-7 weeks during or after completion of androgen
deprivation therapy.

Patients remain off treatment until PSA relapse, defined as an increase in the PSA level to
the pre-androgen deprivation therapy level or > 10 ng/mL, whichever is smaller. Once the
patient meets the criteria for re-treatment with androgen deprivation therapy, they are
removed from study.

After completion of study therapy, patients are followed periodically.

DISEASE CHARACTERISTICS:

- Histologically confirmed adenocarcinoma of the prostate

- Stage N1, N2, N3, M1a, M1b, M1c disease with ≤ 5 metastatic lesions

- If the diagnosis of metastasis is based solely on imaging CT scan or MRI,
the longitudinal diameter of the lymph node (LN) must be ≥ 2.0 cm

- If the LN is positive on PET or Prostascint scan, the longitudinal diameter
of the LN must be ≥ 1.5 cm on CT scan or MRI

- Measurable disease documented by x-rays, scans, or physical examination within the
past 28 days OR nonmeasurable disease assessed within the past 42 days

- Has received up to 36 weeks of adjuvant androgen deprivation therapy for metastatic
disease OR is planning to receive 36 weeks of adjuvant androgen deprivation therapy

- Patients who are not receiving androgen deprivation therapy at the time of
enrollment undergo androgen deprivation therapy

- Patients who are already receiving androgen deprivation therapy at the time of
enrollment will continue treatment, as described above, until they have received
a total of 36 weeks of treatment

- Patients who have enrolled on study after completion of androgen deprivation
therapy or near the end of their treatment course must have serum testosterone
level at castrate levels (< 50 ng/dL)

- Documented PSA level > 2 ng/mL prior to onset of androgen deprivation

- No disease that is refractory to hormone therapy, as demonstrated by occurrence of 1
of the following while on luteinizing hormone-releasing agonist therapy:

- Increase in PSA by 25% over baseline to at least > 2 ng/mL on two consecutive PSA
measurements

- Increase by 20% in the sum of longest diameters of target measurable lesions over
the smallest sum observed (over baseline if no decrease during therapy) using the
same techniques as were used at baseline

- Clear worsening of any nonmeasurable disease

- Reappearance of any lesion that had disappeared

- Appearance of any new lesion

- No history of brain metastases or current treated or untreated brain metastases

PATIENT CHARACTERISTICS:

- WHO performance status 0-2

- Able to understand the nature of the trial

- No unstable or severe concurrent medical conditions

- No active uncontrolled infection

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- Recovered from prior systemic therapy and other previously administered
investigational agents

- No prior radiotherapy or chemotherapy for metastatic disease

- Prior neoadjuvant and adjuvant chemotherapy allowed

- May have received one prior systemic non-chemotherapeutic treatment (i.e.,
immunotherapy, receptor tyrosine kinase inhibitor, antiangiogenic agent, or
differentiating agent) for recurrent or metastatic disease

- More than 2 years since prior adjuvant therapy before androgen deprivation therapy for
metastatic disease AND patient must remain hormone-sensitive

- Sufficient time must have elapsed since other prior investigational agents to ensure
that drug interactions do not occur during this study

- No history of orchiectomy

- Concurrent androgen deprivation therapy for metastatic disease allowed

- Concurrent bisphosphonates allowed at the discretion of the treating physician

- No other concurrent investigational agents