11C-Choline PET/CT image-guided tomotherapy treatment of lymph nodal relapse in prostate cancer patients

Objectives To evaluate a) the role of 11C-Choline (Chol) PET/CT as image-guide tool for Tomotherapy treatment (HTT) of lymph nodal relapse in prostate cancer patients and b) the efficacy and acute/late toxicity of HTT in these patients.

Methods 27 prostate cancer pts with a biochemical recurrence after primary treatment (PSA0 >0.2ng/ml) were treated by hypofractionated HTT on lymph nodal relapse (n=24 at para-aortic and/or pelvic level and n=3 at mediastinal level), as detected by a re-staging Chol PET/CT (PET/CT0). HTT doses ranged from 42Gy/6 fractions and 71Gy/28 fractions. Treatment efficacy was evaluated by PSA value (PSA1) in all pts and by an additional Chol PET/CT (PET/CT1) in 15 pts and compared to basal evaluations.

Results With respect to PSA0, PSA1 showed a significant decrease after HTT in 24/27 pts. Of the 15 pts with PET/CT1 evaluation, 13 presented a Complete and 2 a Partial Metabolic Response. During follow-up (median 18 months, range 3-41), none of the 27 pts had progression in irradiated area, 3 pts showed disease in other sites and one patients died for tumour progression. HTT treatment was well tolerated. Acute toxicity observed was: 10 G1 cases (4 at genitor-urinary -GU and 6 at upper-gastro intestinal level -uGe), 1 G2 uGe and 1 G2 GU. No G3-G4 acute side effects, neither late toxicity were reported.

Conclusions Chol PET/CT-guided HTT is safe and effective on lymph nodal relapses in prostate cancer after primary treatment, as demonstrated by the good rate of local control. If our data will be confirmed by larger population and longer follow-up, HTT guided by Chol PET/CT could be a valid treatment option in these patients