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29 results on '"Hoekstra, Carel"'

3. Advances in radiotherapy and its impact on second primary cancer risk:A multi-center cohort study in prostate cancer patients

Author

Jahreiß, Marie Christina, Hoogeman, Mischa, Aben, Katja KH, Dirkx, Maarten, Snieders, Renier, Pos, Floris J., Janssen, Tomas, Dekker, Andre, Vanneste, Ben, Minken, Andre, Hoekstra, Carel, Smeenk, Robert J., Incrocci, Luca, Heemsbergen, Wilma D., Jahreiß, Marie Christina, Hoogeman, Mischa, Aben, Katja KH, Dirkx, Maarten, Snieders, Renier, Pos, Floris J., Janssen, Tomas, Dekker, Andre, Vanneste, Ben, Minken, Andre, Hoekstra, Carel, Smeenk, Robert J., Incrocci, Luca, and Heemsbergen, Wilma D.

Abstract

Background: Modelling studies suggest that advanced intensity-modulated radiotherapy may increase second primary cancer (SPC) risks, due to increased radiation exposure of tissues located outside the treatment fields. In the current study we investigated the association between SPC risks and characteristics of applied external beam radiotherapy (EBRT) protocols for localized prostate cancer (PCa). Methods: We collected EBRT protocol characteristics (2000–2016) from five Dutch RT institutes for the 3D-CRT and advanced EBRT era (N = 7908). From the Netherlands Cancer Registry we obtained patient/tumour characteristics, SPC data, and survival information. Standardized incidence ratios (SIR) were calculated for pelvis and non-pelvis SPC. Nationwide SIRs were calculated as a reference, using calendar period as a proxy to label 3D-CRT/advanced EBRT. Results: From 2000-2006, 3D-CRT with 68–78 Gy in 2 Gy fractions, delivered with 10–23 MV and weekly portal imaging was the most dominant protocol. By the year 2010 all institutes routinely used advanced EBRT (IMRT, VMAT, tomotherapy), mainly delivering 78 Gy in 2 Gy fractions, using various kV/MV imaging protocols. Sixteen percent (N = 1268) developed ≥ 1 SPC. SIRs for pelvis and non-pelvis SPC (all institutes, advanced EBRT vs 3D-CRT) were 1.17 (1.00–1.36) vs 1.39 (1.21–1.59), and 1.01 (0.89–1.07) vs 1.03 (0.94–1.13), respectively. Nationwide non-pelvis SIR was 1.07 (1.01–1.13) vs 1.02 (0.98–1.07). Other RT protocol characteristics did not correlate with SPC endpoints. Conclusion: None of the studied RT characteristics of advanced EBRT was associated with increased out-of-field SPC risks. With constantly evolving EBRT protocols, evaluation of associated SPC risks remains important.

Published
2023

5. Multivariable model development and internal validation for prostate cancer specific survival and overall survival after whole-gland salvage Iodine-125 prostate brachytherapy

Author

Peters, Max, van der Voort van Zyp, Jochem R.N., Moerland, Marinus A., Hoekstra, Carel J., van de Pol, Sandrine, Westendorp, Hendrik, Maenhout, Metha, Kattevilder, Rob, Verkooijen, Helena M., van Rossum, Peter S.N., Ahmed, Hashim U., Shah, Taimur T., Emberton, Mark, and van Vulpen, Marco

Published
2016
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9. Impact of Advanced Radiotherapy on Second Primary Cancer Risk in Prostate Cancer Survivors: A Nationwide Cohort Study

Author

Jahreiß, Marie-Christina, primary, Heemsbergen, Wilma D., additional, van Santvoort, Bo, additional, Hoogeman, Mischa, additional, Dirkx, Maarten, additional, Pos, Floris J., additional, Janssen, Tomas, additional, Dekker, Andre, additional, Vanneste, Ben, additional, Minken, Andre, additional, Hoekstra, Carel, additional, Smeenk, Robert J., additional, van Oort, Inge M., additional, Bangma, Chris H., additional, Incrocci, Luca, additional, and Aben, Katja K. H., additional

Published
2021
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10. Impact of Advanced Radiotherapy on Second Primary Cancer Risk in Prostate Cancer Survivors:A Nationwide Cohort Study

Author

Jahreiß, Marie Christina, Heemsbergen, Wilma D., van Santvoort, Bo, Hoogeman, Mischa, Dirkx, Maarten, Pos, Floris J., Janssen, Tomas, Dekker, Andre, Vanneste, Ben, Minken, Andre, Hoekstra, Carel, Smeenk, Robert J., van Oort, Inge M., Bangma, Chris H., Incrocci, Luca, Aben, Katja K.H., Jahreiß, Marie Christina, Heemsbergen, Wilma D., van Santvoort, Bo, Hoogeman, Mischa, Dirkx, Maarten, Pos, Floris J., Janssen, Tomas, Dekker, Andre, Vanneste, Ben, Minken, Andre, Hoekstra, Carel, Smeenk, Robert J., van Oort, Inge M., Bangma, Chris H., Incrocci, Luca, and Aben, Katja K.H.

Abstract

Purpose: External Beam Radiotherapy (EBRT) techniques dramatically changed over the years. This may have affected the risk of radiation-induced second primary cancers (SPC), due to increased irradiated low dose volumes and scatter radiation. We investigated whether patterns of SPC after EBRT have changed over the years in prostate cancer (PCa) survivors. Materials and Methods: PCa survivors diagnosed between 1990-2014 were selected from the Netherlands Cancer Registry. Patients treated with EBRT were divided in three time periods, representing 2-dimensional Radiotherapy (RT), 3-dimensional conformal RT (3D-CRT), and the advanced RT (AdvRT) era. Standardized incidence ratios (SIR) and absolute excess risks (AER) were calculated to estimate relative and excess absolute SPC risks. Sub-hazard ratios (sHRs) were calculated to compare SPC rates between the EBRT and prostatectomy cohort. SPCs were categorized by subsite and anatomic region. Results: PCa survivors who received EBRT had an increased risk of developing a solid SPC (SIR=1.08; 1.05-1.11), especially in patients aged <70 years (SIR=1.13; 1.09-1.16). Pelvic SPC risks were increased (SIR=1.28; 1.23-1.34), with no obvious differences between the three EBRT eras. Non-pelvic SPC were only significantly increased in the AdvRT era (SIR=1.08; 1.02-1.14), in particular for the 1-5 year follow-up period. Comparing the EBRT cohort to the prostatectomy cohort, again an increased pelvic SPC risk was found for all EBRT periods (sHRs= 1.61, 1.47-1.76). Increased non-pelvic SPC risks were present for all RT eras and highest for the AdvRT period (sHRs=1.17, 1.06-1.29). Conclusion: SPC risk in patients with EBRT is increased and remained throughout the different EBRT eras. The risk of developing a SPC outside the pelvic area changed unfavorably in the AdvRT era. Prolonged follow-up is needed to confirm this observation. Whether this is associated with increased irradiated low-dose volumes and scatter, or other changes in cl

Published
2021

13. Regional radiotherapy versus an axillary lymph node dissection after lumpectomy: a safe alternative for an axillary lymph node dissection in a clinically uninvolved axilla in breast cancer. A case control study with 10 years follow up

Author

Elferink Marloes AG, Siesling Sabine, Spruit Patty H, Vonk Ernest JA, and Hoekstra Carel JM

Subjects
Medical physics. Medical radiology. Nuclear medicine, R895-920, Neoplasms. Tumors. Oncology. Including cancer and carcinogens, RC254-282
Abstract

Abstract Background The standard treatment of the axilla in breast cancer used to be an axillary lymph node dissection. An axillary lymph node dissection is known to give substantial risks of morbidity. In recent years the sentinel node biopsy has become common practice. Future randomized study results will determine whether the expected decrease in morbidity can be proven. Methods Before the introduction of the sentinel node biopsy, we conducted a study in which 180 women of 50 years and older with T1/T2 cN0 breast cancer were treated with breast conserving therapy. Instead of an axillary lymph node dissection regional radiotherapy was given in combination with tamoxifen (RT-group). The study group was compared with 341 patients, with the same patient and tumour characteristics, treated with an axillary lymph node dissection (S-group). Results The treatment groups were comparable, except for age. The RT-group was significantly older than the S-group. The median follow up was 7.2 years. The regional relapse rates were low and equal in both treatment groups, 1.1% in RT-group versus 1.5% in S-group at 5 years. The overall survival was similar; the disease free survival was significant better in the RT-group. Conclusion Regional recurrence rates after regional radiotherapy are very low and equal to an axillary lymphnode dissection.

Published
2007
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14. Cone-beam CT-based adaptive planning improves permanent prostate brachytherapy dosimetry : An analysis of 1266 patients

Author

Westendorp, Hendrik, Hoekstra, Carel J., Immerzeel, Jos J., Van De Pol, Sandrine M.G., Niël, Charles G.H.J., Kattevilder, Robert A.J., Nuver, Tonnis T., Minken, André W., Moerland, Marinus A., Westendorp, Hendrik, Hoekstra, Carel J., Immerzeel, Jos J., Van De Pol, Sandrine M.G., Niël, Charles G.H.J., Kattevilder, Robert A.J., Nuver, Tonnis T., Minken, André W., and Moerland, Marinus A.

Published
2017

15. Cone-beam CT-based adaptive planning improves permanent prostate brachytherapy dosimetry: An analysis of 1266 patients

Author

Klinische Fysica RT, Cancer, Westendorp, Hendrik, Hoekstra, Carel J., Immerzeel, Jos J., Van De Pol, Sandrine M.G., Niël, Charles G.H.J., Kattevilder, Robert A.J., Nuver, Tonnis T., Minken, André W., Moerland, Marinus A., Klinische Fysica RT, Cancer, Westendorp, Hendrik, Hoekstra, Carel J., Immerzeel, Jos J., Van De Pol, Sandrine M.G., Niël, Charles G.H.J., Kattevilder, Robert A.J., Nuver, Tonnis T., Minken, André W., and Moerland, Marinus A.

Published
2017

18. Rectal dose constraints for salvage iodine-125 prostate brachytherapy

Author

Onderzoek Radiotherapie, Cancer, MS Radiotherapie, Arts-assistenten Radiotherapie, Divisie Beeld & Oncologie, Radiotherapie, Peters, Max, Hoekstra, Carel J., van der Voort van Zyp, Jochem, Westendorp, Hendrik, van de Pol, Sandrine M. G., Moerland, Rien, Maenhout, Metha, Kattevilder, Rob, van Vulpen, Marco, Onderzoek Radiotherapie, Cancer, MS Radiotherapie, Arts-assistenten Radiotherapie, Divisie Beeld & Oncologie, Radiotherapie, Peters, Max, Hoekstra, Carel J., van der Voort van Zyp, Jochem, Westendorp, Hendrik, van de Pol, Sandrine M. G., Moerland, Rien, Maenhout, Metha, Kattevilder, Rob, and van Vulpen, Marco

Published
2016

19. Multivariable model development and internal validation for prostate cancer specific survival and overall survival after whole-gland salvage Iodine-125 prostate brachytherapy

Author

Onderzoek Radiotherapie, Cancer, MS Radiotherapie, Klinische Fysica RT, Arts-assistenten Radiotherapie, Trialbureau Beeld, Circulatory Health, Epi Kanker Team A, JC onderzoeksprogramma Kanker, Fysica Radiotherapie Research, Radiotherapie, Peters, Max, van der Voort van Zyp, Jochem R N, Moerland, Marinus A, Hoekstra, Carel J, van de Pol, Sandrine, Westendorp, Hendrik, Maenhout, Metha, Kattevilder, Rob, Verkooijen, Helena M, van Rossum, Peter S N, Ahmed, Hashim U, Shah, Taimur T, Emberton, Mark, van Vulpen, Marco, Onderzoek Radiotherapie, Cancer, MS Radiotherapie, Klinische Fysica RT, Arts-assistenten Radiotherapie, Trialbureau Beeld, Circulatory Health, Epi Kanker Team A, JC onderzoeksprogramma Kanker, Fysica Radiotherapie Research, Radiotherapie, Peters, Max, van der Voort van Zyp, Jochem R N, Moerland, Marinus A, Hoekstra, Carel J, van de Pol, Sandrine, Westendorp, Hendrik, Maenhout, Metha, Kattevilder, Rob, Verkooijen, Helena M, van Rossum, Peter S N, Ahmed, Hashim U, Shah, Taimur T, Emberton, Mark, and van Vulpen, Marco

Published
2016

21. Urethral and bladder dosimetry of total and focal salvage Iodine-125 prostate brachytherapy : Late toxicity and dose constraints

Author

Peters, Max, Van Der Voort Van Zyp, Jochem, Hoekstra, Carel, Westendorp, Hendrik, Van De Pol, Sandrine, Moerland, Marinus, Maenhout, Metha, Kattevilder, Rob, Van Vulpen, Marco, Peters, Max, Van Der Voort Van Zyp, Jochem, Hoekstra, Carel, Westendorp, Hendrik, Van De Pol, Sandrine, Moerland, Marinus, Maenhout, Metha, Kattevilder, Rob, and Van Vulpen, Marco

Published
2015

22. Urethral and bladder dosimetry of total and focal salvage Iodine-125 prostate brachytherapy: Late toxicity and dose constraints

Author

UMC Utrecht, Onderzoek Radiotherapie, Cancer, MS Radiotherapie, Arts-assistenten Radiotherapie, Divisie Beeld & Oncologie, Radiotherapie, Peters, Max, Van Der Voort Van Zyp, Jochem, Hoekstra, Carel, Westendorp, Hendrik, Van De Pol, Sandrine, Moerland, Marinus, Maenhout, Metha, Kattevilder, Rob, Van Vulpen, Marco, UMC Utrecht, Onderzoek Radiotherapie, Cancer, MS Radiotherapie, Arts-assistenten Radiotherapie, Divisie Beeld & Oncologie, Radiotherapie, Peters, Max, Van Der Voort Van Zyp, Jochem, Hoekstra, Carel, Westendorp, Hendrik, Van De Pol, Sandrine, Moerland, Marinus, Maenhout, Metha, Kattevilder, Rob, and Van Vulpen, Marco

Published
2015

28. Objective automated assessment of time trends in prostate edema after 125I implantation

Author

Westendorp, Hendrik, Kattevilder, Rob, van ’t Riet, Arie, Minken, André W., Nuver, Tonnis T., Immerzeel, Jos J., and Hoekstra, Carel J.

Subjects
*PROSTATE diseases, *EDEMA, *RADIOISOTOPE brachytherapy, *TOMOGRAPHY, *ARTIFICIAL implants, *MATHEMATICAL models
Abstract

Abstract: Purpose: To present an objective automated method to determine time trends in prostatic edema resulting from iodine-125 brachytherapy. Methods and Materials: We followed 20 patients, implanted with stranded seeds, with seven consecutive CT scans to establish a time trend in prostate edema. Seed positions were obtained automatically from the CT series. The change in seed positions was used as surrogate for edema. Two approaches were applied to model changes in volume. (1) A cylindrical model: seeds from the compared distribution were linked to the reference distribution of Day 28. After alignment, the compared distribution was scaled in cylindrical coordinates, leading to the changes in radial and craniocaudal directions. The volume changes were calculated using these scaling factors. (2) A spherical model: distances of seeds to the center of gravity of all seeds were used as a measure to model volume changes. Results: With Day 28 as reference, the observed volume changes were smaller than 18% ± 6% (1 standard deviation) for the cylindrical model and 12% ± 7% for the spherical model. One day after implantation, the implanted prostate was less than 10% larger than in the reference scan for both models. Apart from Day 0, both models showed similar volume changes. Conclusions: We present an objective automated method to determine changes in the implanted prostate volume, eliminating the influence of an observer in the assessment of the prostate size. The implanted volume change was less than 18% ± 7% for the studied group of 20 patients. Edema was 9% ± 5% from 1 day after implantation onward. [Copyright &y& Elsevier]

Published
2012
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