Low incidence of new biochemical and clinical XXXX following hypofractionated stereotactic body radiation therapy (SBRT) monotherapy for low- to intermediate-risk @entity263 .

@entity1 @entity251 @entity137 @entity263 @entity6126
BACKGROUND: The CyberKnife is an appealing delivery system for hypofractionated stereotactic body radiation therapy (SBRT) because of its ability to deliver highly conformal radiation therapy to moving targets. This conformity is achieved via 100s of non-coplanar radiation beams, which could potentially increase transitory testicular irradiation and result in post-therapy @entity6126 . We report on our early experience with CyberKnife SBRT for low- to intermediate-risk @entity263 @entity1 and assess the rate of inducing biochemical and clinical @entity6126 . METHODS: Twenty-six @entity1 were treated with hypofractionated SBRT to a dose of 36.25 Gy in 5 fractions. All @entity1 had histologically confirmed low- to intermediate-risk @entity263 (clinical stage  <= T2b, Gleason score  <= 7, PSA  <= 20 ng/ml). PSA and total @entity251 levels were obtained pre-treatment, 1 month post-treatment and every 3 months thereafter, for 1 year. Biochemical @entity6126 was defined as a total serum @entity251 level below 8 nmol/L. Urinary and gastrointestinal @entity137 was assessed using Common @entity137 Criteria v3; quality of life was assessed using the American Urological Association Symptom Score, Sexual Health Inventory for @entity1 and Expanded @entity263 Index Composite questionnaires. RESULTS: All 26 @entity1 completed the treatment with a median 15 months (range, 13-19 months) follow-up. Median pre-treatment PSA was 5.75 ng/ml (range, 2.3-10.3 ng/ml), and a decrease to a median of 0.7 ng/ml (range, 0.2-1.8 ng/ml) was observed by one year post-treatment. The median pre-treatment total serum @entity251 level was 13.81 nmol/L (range, 5.55 - 39.87 nmol/L). Post-treatment @entity251 levels slowly decreased with the median value at one year follow-up of 10.53 nmol/L, significantly lower than the pre-treatment value (p < 0.013). The median absolute fall was 3.28 nmol/L and the median percent fall was 23.75%. There was no increase in biochemical @entity6126 at one year post-treatment. Average EPIC sexual and hormonal scores were not significantly changed by one year post-treatment. CONCLUSIONS: Hypofractionated SBRT offers the radiobiological benefit of a large fraction size and is well-tolerated by @entity1 with low- to intermediate-risk @entity263 . Early results are encouraging with an excellent biochemical response. The rate of new biochemical and clinical @entity6126 was low one year after treatment.
