Helical tomotherapy treatment planning of lymph-node relapses in prostate cancer: Clinical value of 11C-Choline PET/CT

Objectives To evaluate the role of 11C-Choline PET/CT as image-guide tool for tomotherapy treatment(HTT)of lymph-node relapses and for treatment monitoring in prostate cancer patients.

Methods 31 prostate cancer pts with biochemical recurrence after primary treatment (mean PSA0:14,12 ng/ml) performed PET/CT0 for restaging and planning treatment.PET/TC0 positive pelvic and abdominal lymph nodes were treated with high dose using simultaneous boost (n=34 treatments).After the end of HTT PSA1 was measured and compared to PSA0 to evaluate biochemical response;in 24/34 pts a PET/CT1 scan was repeated to assess metabolic response.In 25/34 treatments, a further PSA2 measurement was recorded; in 13/25 cases a PET/CT2 was performed.PSA2 and PET/CT2 were compared to the basal ones.

Results PET/CT0 showed 34 sites of nodal involvement (20 pelvic,8 abdominal,6 pelvic+abdominal) that were included in treatment planning.PSA1 (mean 4.55 ng/ml; range 0.00-46.39 ng/ml) showed biochemical response after HTT in 31/34 cases and progression in 3/34 while PSA2 (mean 0.98ng/ml; range 0.00-10.71 ng/ml) in 19/25 and 6/25 treatments respectively. Metabolic response at treated areas at PET/CT1 resulted:complete (CMR) in 11/24, partial (PMR) in 9/24, progression disease (PD) in 2/24 and stable disease (SD) in 2/24. In 4/24 cases distant metastases were detected. PET/CT2 showed CMR in 11/13, PMR in 1/13 and PD in 1/13 on treated areas. Distant metastases occurred in 4/13 cases.

Conclusions 11C-Choline PET/CT is a valuable tool for planning and monitoring HTT treatment on lymph nodal relapse. HTT and concomitant systemic therapy are effective as demonstrated by the good rate of local control