Georgios Chatzikonstantinou
Goethe University Frankfurt
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Featured researches published by Georgios Chatzikonstantinou.
Radiation Oncology | 2013
Nikolaos Tselis; Ulf W. Tunn; Georgios Chatzikonstantinou; Natasa Milickovic; Dimos Baltas; Markus Ratka; Nikolaos Zamboglou
BackgroundTo report the clinical outcome of high dose rate brachytherapy as sole treatment for clinically localised prostate cancer.MethodsBetween March 2004 and January 2008, a total of 351 consecutive patients with clinically localised prostate cancer were treated with transrectal ultrasound guided high dose rate brachytherapy. The prescribed dose was 38.0 Gy in four fractions (two implants of two fractions each of 9.5 Gy with an interval of 14 days between the implants) delivered to an intraoperative transrectal ultrasound real-time defined planning treatment volume. Biochemical failure was defined according to the Phoenix Consensus and toxicity evaluated using the Common Toxicity Criteria for Adverse Events version 3.ResultsThe median follow-up time was 59.3 months. The 36 and 60 month biochemical control and metastasis-free survival rates were respectively 98%, 94% and 99%, 98%. Toxicity was scored per event with 4.8% acute Grade 3 genitourinary and no acute Grade 3 gastrointestinal toxicity. Late Grade 3 genitourinary and gastrointestinal toxicity were respectively 3.4% and 1.4%. No instances of Grade 4 or greater acute or late adverse events were reported.ConclusionsOur results confirm high dose rate brachytherapy as safe and effective monotherapy for clinically organ-confined prostate cancer.
Brachytherapy | 2012
Nikolaos Tselis; Georgios Chatzikonstantinou; Christos Kolotas; Natasa Milickovic; Dimos Baltas; Tje Lin Chung; Nikolaos Zamboglou
PURPOSE To report our results of computed tomography (CT)-guided interstitial high-dose-rate (HDR) brachytherapy (BRT) in the local treatment of inoperable primary and secondary liver malignancies. METHODS AND MATERIALS Between 2000 and 2009, 31 patients underwent a total of 42 BRT procedures for 36 hepatic lesions exceeding 4 cm and located adjacent to the liver hilum and bile duct bifurcation. The median tumor volume was 99 cm(3) (range, 46-1348 cm(3)). The median age was 64 years (range, 27-85 years). The HDR-BRT delivered a median total physical dose of 13.0 Gy (range, 7.0-32.0 Gy) in twice daily fractions of median 7.0 Gy (range, 4.0-10.0 Gy) in 14 patients and in once daily fractions of median 8.0 Gy (range, 7.0-14.0 Gy) in 17 patients. RESULTS The median followup was 13.3 months with an overall survival rate of 66% at 1 year. The local control rate for patients with metastatic lesions was 79%, 59%, and 59%, and for the subgroup with primary hepatic tumors 88%, 50%, and 50% at 1, 2, and 3 years, respectively. Severe side effects occurred in 4.7% of BRT procedures with no treatment-related deaths. CONCLUSIONS Our results confirm CT-guided interstitial HDR-BRT to be a safe procedure for the local treatment of inoperable liver malignancies unsuitable for thermal ablation.
Radiotherapy and Oncology | 2017
Iosif Strouthos; Nikolaos Tselis; Georgios Chatzikonstantinou; Saeed Butt; Dimos Baltas; Dimitra Bon; Natasa Milickovic; Nikolaos Zamboglou
BACKGROUND AND PURPOSE To evaluate the oncological outcome of a three-implant high dose rate (HDR) brachytherapy (BRT) protocol as monotherapy for clinically localised prostate cancer. MATERIAL AND METHODS Between February 2008 and December 2012, 450 consecutive patients with clinically localised prostate cancer were treated with HDR monotherapy. The cohort comprised of 198 low-, 135 intermediate- and 117 high risk patients being treated with three single-fraction implants of 11.5Gy delivered to an intraoperative real-time, transrectal ultrasound defined planning treatment volume up to a total physical dose of 34.5Gy with an interfractional interval of 21days. Fifty-eight patients (12.8%) received ADT, 32 of whom were high- and 26 intermediate-risk. Biochemical failure was defined according to the Phoenix Consensus Criteria and genitourinary/gastrointestinal toxicity evaluated using the Common Toxicity Criteria for Adverse Events version 3.0. RESULTS The median follow-up time was 56.3months. The 60-month overall survival, biochemical control and metastasis-free-survival rates were 96.2%, 95.0% and 99.0%, respectively. Toxicity was scored per event with late Grade 2 and 3 genitourinary adverse events of 14.2% and 0.8%, respectively. Late Grade 2 gastrointestinal toxicity amounted 0.4% with no instances of Grade 3 or greater late adverse events to be reported. CONCLUSIONS Our results confirm HDR BRT to be a safe and effective monotherapeutic treatment modality for clinically localised prostate cancer.
Radiotherapy and Oncology | 2018
Iosif Strouthos; Georgios Chatzikonstantinou; Nikolaos Zamboglou; Natasa Milickovic; S. Papaioannou; Dimitra Bon; Constantinos Zamboglou; Claus Rödel; Dimos Baltas; Nikolaos Tselis
PURPOSE To report the clinical outcomes and treatment-related toxicities after combined high-dose-rate (HDR) brachytherapy (BRT) with external beam radiotherapy (EBRT) for patients with clinically localised high-risk prostate cancer. MATERIAL AND METHODS Between 2008 and 2012, three hundred and three consecutive patients with organ-confined high-risk prostate cancer were treated with definitive radiotherapy consisting of HDR-BRT followed by supplemental EBRT. The transrectal 3D-ultrasound-based HDR-BRT boost consisted of two single-fraction implants of 10.5 Gy, prescribed to the 90% of the gland (D90), for a total physical dose of 21.0 Gy delivered to the prostatic gland. EBRT was delivered with conventional fractionation, prescribing 45.0 Gy to the prostatic gland and seminal vesicles. Biochemical failure was defined according to the Phoenix Consensus Criteria, genitourinary (GU)/gastrointestinal (GI) toxicity was evaluated using the Common Toxicity Criteria for Adverse Events (version 3.0). RESULTS The median follow-up was 71.6 months. The 7-year overall survival, biochemical control and metastasis-free-survival rates for the entire cohort were 85.7%, 88.3% and 93.8%, respectively. Androgen deprivation therapy was initiated prior to treatment for 92.7% of patients with a median duration of 12 months. Toxicity was scored per event with late Grade 2, 3 and 4 GU adverse events and was found to be 15.3%, 2.2% and 0.3%, respectively. Late Grade 2 GI toxicity accounted for 0.3% with no instances of Grade 3 or higher late adverse events. CONCLUSION HDR-BRT with supplemental EBRT results in low biochemical relapse-free survival rates associated with a very low incidence of higher-grade late adverse events.
European Radiology | 2013
Nikolaos Tselis; Georgios Chatzikonstantinou; Christos Kolotas; Natasa Milickovic; Dimos Baltas; Nikolaos Zamboglou
Clinical Oncology | 2017
Nikolaos Tselis; Peter Hoskin; Dimos Baltas; V. Strnad; Nikolaos Zamboglou; Claus Rödel; Georgios Chatzikonstantinou
Strahlentherapie Und Onkologie | 2017
Iosif Strouthos; Georgios Chatzikonstantinou; Nikolaos Tselis; Dimitra Bon; Efstratios Karagiannis; Eleni Zoga; Konstantinos Ferentinos; Julia Maximenko; Vassiliki Nikolettou-Fischer; Nikolaos Zamboglou
Strahlentherapie Und Onkologie | 2018
Georgios Chatzikonstantinou; Nikolaos Zamboglou; Eleftherios Archavlis; Iosif Strouthos; Eleni Zoga; N. Milickovic; Basil Hilaris; Dimos Baltas; Claus Rödel; Nikolaos Tselis
Radiotherapy and Oncology | 2018
Iosif Strouthos; Georgios Chatzikonstantinou; Nikolaos Tselis; Natasa Milickovic; S. Papaioannou; Saeed Butt; A.L. Grosu; Dimos Baltas; Nikolaos Zamboglou
Archive | 2018
Nikolaos Tselis; Georgios Chatzikonstantinou