This is a prospective, open label, non-randomized, single site, phase I/II study of the safety and utility of 11C-Choline PET scans for delineation of intraprostatic lesions in subjects with localized intermediate risk prostate cancer and subsequent Enhanced EBRT (External Beam Radiation Therapy) to monitor toxicity, therapeutic response and recurrence.
The estimated total number of subjects required for protocol enrollment and baseline 11C-Choline PET scans is 63; however, the protocol will complete accrual only when 29 subjects have commenced Enhanced EBRT or the outlined stopping rules require a halt to accrual. Twenty-nine (29) subjects treated with Enhanced EBRT are required to assess the toxicity of this treatment based on the statistical analysis outlined in the protocol. Subjects will receive a fixed dose (400 MBq, 10%) of 11C-Choline and PET/CT imaging with co-registration 3T MRI imaging prior to Enhanced EBRT and two further doses of 11C-Choline at two intervals (3 and 6 months) thereafter.
Subjects with suitable intraprostatic lesion delineation with 11C-Choline will proceed to Enhanced EBRT, consisting of a dose prescription of 78 Gy in 25 fractions to the intraprostatic lesions and 68 Gy in 25 fractions (simultaneously) to the prostate gland. Subjects without suitable intraprostatic lesion delineation will be treated with Cross Cancer Institute standard of care EBRT and undergo follow-up for biochemical recurrence per protocol to determine the prognostic value of the baseline PET findings.
Subjects will be monitored for 11C-Choline safety and efficacy and for EBRT safety / toxicity and efficacy.
11C-Choline PET image intraprostatic lesion(s) will be analyzed by the relative uptake scores (RUS), tumor to background ratios (T/B) and SUVmax parameters. Adequate delineation will be determined by a lesion with tumor to background ration ≥2. This is defined in section 10.
11C-Choline PET image parameters will be correlated with other measures of progression and survival including biochemical disease free survival as indicators of Enhanced EBRT response.
Efficacy of 11C-Choline delineated Enhanced EBRT will be evaluated by progression and survival analysis compared to historical data from this population.
Safety of 11C-Choline will be determined by: vital signs, blood hematology and clinical biochemistry profile (pre-injection, post-imaging) and adverse event collection.
Safety/toxicity of 11C-Choline delineated Enhanced EBRT will be determined by adverse event collection, primarily for genitourinary and gastrointestinal toxicity and compared to historical data from this population.
