The aim of this study was to evaluate the effectiveness of CyberKnife-based stereotactic ablative radiotherapy on prostate cancer lymph node metastases. Our material consisted of 18 patients with 31 metastatic lymph nodes irradiated between 2011 and 2014 using CyberKnife-based stereotactic ablative radiotherapy. Patients were irradiated using fraction dose varied from 6 to 15 Gy (median 10), to the total dose of 24 to 45 Gy (median 30). Irradiated lymph node size varied from 0.4 to 4.0 cm. In all, 9 patients had single lymph node metastasis and 9 patients had metastases of 2 to 4 lymph nodes. Prostate-specific antigen concentration before radiotherapy varied from 0.01 to 15.58 (mean 6.97; median 4.66). All patients at the time of radiotherapy and follow-up received androgen deprivation therapy. Mann-Whitney U, Kaplan-Meier method, and log-rank tests were used in statistical analysis. We obtained the following results: after CyberKnife stereotactic ablative radiotherapy, prostate-specific antigen concentration dropped in majority of cases and during the last control varied from 0.00 to 258.00 (median 2.5), and was lower in patients without dissemination to other organs (P = .01). Complete regression was found in 12 lesions, stable disease in 13, and progression in 4. In 7 patients, the dissemination to other organs occurred. Our results allow us to conclude that CyberKnife stereotactic ablative radiotherapy of prostate cancer lymph node oligometastases gives good local control and relatively good prostate-specific antigen response.

The aim of the study was to evaluate the effectiveness and toxicity of CyberKnife (CK) stereotactic radiosurgery (SRS) and stereotactic ablative radiation therapy (SABR) of patients with prostate cancer bone metastases. Analysis of prognostic and predictive factors was also performed.Material consisted of 51 patients with 71 bone oligometastases treated using CK SRS/SABR. In half of the patients single lesion was treated, in half 2-5 lesions. Median PSA concentration at the time of metastasis detection was 5.75 ng/ml. Total dose of 6-45Gy (median 20) was delivered with 1-5 fractions of 6-15 Gy (median 9). Biologic equivalent dose (BED) (α/ β=1.6) over 100 Gy was delivered to 45 lesions (63%) in 38 patients (75%).In statistical analysis Kaplan-Meier method, log-rank test and the Cox proportional hazard model were used. One-, two-and three-year overall survival (OS) was 90%, 76% and 70%, respectively. All patients having PSA concentration lower that 1 ng/ml at last control lived at least three years. One-, two-and three-year local control (LC) was 97%, 70% and 30%. Patients with PSA below 20 ng/ml at the time of metastasis detection had better local control of lesions and lower PSA at the last control. Median of PSA concentration after CK based SRS/SABR remains stable during first 12 months of follow-up, dropped during the next months and at last control was comparable to initial level. Median PSA at last control in patients without disease progression was 1.67ng/ml and 20 patients had PSA below 1.0ng/ml. At the last control 59% of patients had no other metastases. Rapid pain decrease was observed in analysed group and during each control about 90% of patients had pain relief. No major toxicity was observed, 3 patients suffered from fracture of irradiated bone. SRS/SABR of prostate cancer bone oligometastases provides good LC of lesions, excellent pain control without additional toxicity. Patients with PSA concentration below 20ng/ml at the time of metastasis detection have better LC and PSA concentration response.

The highest total dose absorbed in normal tissue was observed with the use of a robotic radiosurgery system and TomoTherapy. These results demonstrate that the exposure of healthy tissue is a dosimetric factor which differentiates the dose delivery methods.

The aim of this study was to evaluate CyberKnife-based radioablation as a salvage treatment for prostate cancer postirradiation relapses based on a group of patients disqualified from available conventional methods of salvage treatment. Thirty-eight patients were treated with a fraction dose varying from 5.5 to 10 Gy (median 7.35) to a total dose of 18 to 36.25 Gy (median 36.25). In all, 55.3% of patients had androgen deprivation therapy during this time. Nine patients had oligometastases in the salvage time. The follow-up varied from 1.6 to 46.4 months (mean 19.7, median 14.4). In all, 92.6% to 97.4% of patients had no gastrointestinal acute adverse effects; no effects higher than G1 were noted. There were particular (up to 4.8%) G2 late gastrointestinal effects. The percentage without genitourinary acute effects varied from 59.1% to 78.9%; 3.7% had G3 toxicity. G3 late genitourinary toxicity appeared 3 times, the maximal percentage being 12.5% (24 months after salvage treatment). The nadir of prostate-specific antigen median was 0.24 ng/mL (9 months after treatment). Twelve (31.6%) patients failed in the timeline of 6 to 42 months after salvage treatment (mean 18.7, median 16.5)—5 due to dissemination. In 2 cases, progression in existing metastases was identified. Five (13.2%) patients had biochemical failure without additional metastases (local relapses); hence, local control was 86.8%. The failure risk is strongly influenced by initial disease stage and presalvage prostate-specific antigen concentration. The obtained results permit us to conclude that such a treatment could be an effective and safe option for prostate cancer postirradiation relapse salvage treatment.

The images of a patient with acromegaly, who previously underwent operation for pituitary adenoma, were obtained. The MRI scan showed a mass in the right cavernous sinus, with biochemical test results positive for the presence of a hormonally active adenoma. The patient was scheduled for CyberKnife radiotherapy. Radiotherapy planning was carried out using MRI and PET/CT scan with somatostatin analog ⁶⁸Ga DOTATATE. The latter showed radiopharmaceutical uptake on the adenomatous residual mass. Contours were drawn on MRI and PET images and were summed up to devise the radiotherapy plan. The patient was treated with a total dose of 24 Gy.