Proton-Based Stereotactic Ablative Body Radiotherapy for Prostate Cancer

Patients with low-risk or intermediate-risk, clinically localized prostate cancer will be
evaluated according to standard of care medical practices. The evaluation includes history
and examination, prostate-specific antigen (PSA) blood testing, and review of the prior
prostate biopsy pathology report; radiology scans (for example, computed tomography [CT],
magnetic resonance imaging [MRI], radionuclide bone scan) may be done also; recently
completed testing may not need to be repeated. Small markers will be placed in the prostate
to guide the proton beam stereotactic ablative body radiotherapy (SABR) treatments, and a
hydrogel spacer may also be placed between the prostate and the rectum to push the rectum
away from the prostate; the hydrogel spacer will dissolve a few months later. Participants
will receive five (5) proton SABR treatments over a two (2) week time period. The study will
have participants complete a quality-of life questionnaire and be evaluated for side-effects
before starting SABR, at the end of SABR, at three (3), six (6) and 12 months after SABR, and
then yearly for five (5) years. Evaluation of the cancer status will follow standard of care
practices for at least ten (10) years.

Inclusion Criteria:

- Male, age ≥ 18 years.

- Histological confirmation of adenocarcinoma of prostatic origin.

- AJCC 7th edition clinical T1b-T2b.

- AJCC clinical staging rules do not include findings from biopsy or imaging.

- Gleason score ≤7 (International Society of Urological Pathologists grades 1-3).

- Serum prostate-specific antigen ≤20 ng/mL.

- Prostate-specific antigen <10 ng/mL, if dutasteride within last 90 days or finasteride
within last 30 days.

- Zubrod performance score 0-1.

- Prostate volume <75-cc, determined by ultrasound, computed tomography or magnetic
resonance imaging (modality with lesser volume is acceptable).

- If neoadjuvant-concurrent androgen suppression is used, the prostate volume after the
start of androgen suppression may be used.

- American Urological Association voiding symptom index ≤15.

- Ability to complete questionnaire(s) by themselves or with assistance.

- Participation in a patient-reported outcomes survey program, inclusive of the Expanded
Prostate Index Composite and CTCAE instruments.

- Ability to provide informed written consent.

Exclusion Criteria:

- Radiological- or pathologically-confirmed seminal vesicle invasion, lymph node
involvement, or distant metastatic disease.

- Radiological- or biopsy-confirmed extraprostatic tumor extension without AJCC 7th
edition clinical T3a classification remain eligible.

- Prior or anticipated external radiotherapy or brachytherapy, transurethral resection
of the prostate, prostatic cryoablation/focused ultrasound/laser therapy,
prostatectomy, or prostatic enucleation.

- Prior bilateral orchiectomy, planned long-term (>6 months duration) androgen
suppression or peripheral androgen blockade, or chemotherapy or immunotherapy for
prostate cancer.

- Prior hemi- or total hip arthroplasty.

- Diabetes mellitus associated with vascular ulcers or wound healing problems,
ulcerative colitis, connective tissue disorder, or chronic (≥120 days) warfarin use
planned.

- Co-morbid severe concurrent disease which, in the judgment of the investigator, would
result in life expectancy <5 years.

- Patients with a left cardiac ventricular assist device are ineligible.

- Patients with an implanted medical electronic device (e.g., cardiac pacemaker) remain
eligible if device monitoring complies with standard of practice (e.g., Cardiology and
Medical Physics evaluation, function checks and during-treatment monitoring).

- Immunocompromised due to HIV positive state.

- Medical or psychiatric conditions that preclude informed decision-making or adherence.

- Prior registration to an Institutional Review Board-approved therapeutic research
study that includes proton beam therapy or photon-based radiotherapy (e.g.,
randomization to proton beam therapy vs. photon-based radiotherapy).