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Papers by Olga Hamming-vrieze

Research paper thumbnail of Impact of daily anatomical changes on EPID-based in vivo dosimetry of VMAT treatments of head-and-neck cancer

Radiotherapy and Oncology, 2015

Target dose verification for VMAT treatments of head-and-neck (H&N) cance... more Target dose verification for VMAT treatments of head-and-neck (H&N) cancer using 3D in vivo EPID dosimetry is expected to be affected by daily anatomical changes. By including these anatomical changes through cone-beam CT (CBCT) information, the magnitude of this effect is investigated. For 20 VMAT-treated H&N cancer patients, all plan-CTs (pCTs), 633 CBCTs and 1266 EPID movies were used to compare four dose distributions per fraction: treatment planning system (TPS) calculated dose and EPID reconstructed in vivo dose, both determined using the pCT and using the CBCT. D2, D50 and D98 of the planning target volume (PTV) were determined per dose distribution. When including daily anatomical information, D2, D50 and D98 of the PTV change on average by 0.0±0.4% according to TPS calculations; the standard deviation of the difference between EPID and TPS target dose changes from 2.5% (pCT) to 2.1% (CBCT). Small time trends are seen for both TPS and EPID dose distributions when using the pCT, which disappear when including CBCT information. Daily anatomical changes hardly influence the target dose distribution for H&N VMAT treatments according to TPS recalculations. Including CBCT information in EPID dose reconstructions slightly improves the agreement with TPS calculations.

Research paper thumbnail of Prospective clinical study on long-term swallowing function and voice quality in advanced head and neck cancer patients treated with concurrent chemoradiotherapy and preventive swallowing exercises

European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery, Jan 8, 2014

Concurrent chemoradiotherapy (CCRT) for advanced head and neck cancer (HNC) is associated with su... more Concurrent chemoradiotherapy (CCRT) for advanced head and neck cancer (HNC) is associated with substantial early and late side effects, most notably regarding swallowing function, but also regarding voice quality and quality of life (QoL). Despite increased awareness/knowledge on acute dysphagia in HNC survivors, long-term (i.e., beyond 5 years) prospectively collected data on objective and subjective treatment-induced functional outcomes (and their impact on QoL) still are scarce. The objective of this study was the assessment of long-term CCRT-induced results on swallowing function and voice quality in advanced HNC patients. The study was conducted as a randomized controlled trial on preventive swallowing rehabilitation (2006-2008) in a tertiary comprehensive HNC center with twenty-two disease-free and evaluable HNC patients as participants. Multidimensional assessment of functional sequels was performed with videofluoroscopy, mouth opening measurements, Functional Oral Intake Sca...

Research paper thumbnail of T3-T4 laryngeal cancer in The Netherlands Cancer Institute; 10-year results of the consistent application of an organ-preserving/-sacrificing protocol

Head & neck, Jan 31, 2014

Both organ-preserving concurrent (chemo)radiotherapy ((C)RT) and organ-sacrificing surgery (total... more Both organ-preserving concurrent (chemo)radiotherapy ((C)RT) and organ-sacrificing surgery (total laryngectomy) are used for treatment of advanced laryngeal cancer. The purpose of this study was to present the assessment of our treatment protocol for T3 (C)RT and T4 disease (total laryngectomy + postoperative RT). We conducted a retrospective cohort study in 182 consecutive patients (1999-2008). The primary outcome was overall survival (OS) in relation to stage and treatment. One hundred two patients received RT (82.4% T3), 20 patients CRT (60.0% T3), and 60 patients total laryngectomy + RT (91.7% T4). Five-year OS: T3 52%, T4 48%, for RT 50%, for CRT 43%, and for total laryngectomy + RT 52%. Five-year laryngectomy-free interval was 72% after RT, and 83% after CRT. There were no differences in survival according to T classification or treatment modality. Because the majority of T3 laryngeal cancers were treated with (C)RT and the majority of T4 with total laryngectomy + RT, this giv...

Research paper thumbnail of Births, Marriages, and Deaths

Research paper thumbnail of Deformable image registration for adaptive radiation therapy of head and neck cancer: accuracy and precision in the presence of tumor changes

International journal of radiation oncology, biology, physics, 2014

To compare deformable image registration (DIR) accuracy and precision for normal and tumor tissue... more To compare deformable image registration (DIR) accuracy and precision for normal and tumor tissues in head and neck cancer patients during the course of radiation therapy (RT). Thirteen patients with oropharyngeal tumors, who underwent submucosal implantation of small gold markers (average 6, range 4-10) around the tumor and were treated with RT were retrospectively selected. Two observers identified 15 anatomical features (landmarks) representative of normal tissues in the planning computed tomography (pCT) scan and in weekly cone beam CTs (CBCTs). Gold markers were digitally removed after semiautomatic identification in pCTs and CBCTs. Subsequently, landmarks and gold markers on pCT were propagated to CBCTs, using a b-spline-based DIR and, for comparison, rigid registration (RR). To account for observer variability, the pair-wise difference analysis of variance method was applied. DIR accuracy (systematic error) and precision (random error) for landmarks and gold markers were quan...

Research paper thumbnail of The association of treatment delay and prognosis in head and neck squamous cell carcinoma (HNSCC) patients in a Dutch comprehensive cancer center

Research paper thumbnail of QUESTIONS FOR THE COLLEGE COUNCIL

Research paper thumbnail of Total Laryngectomy for a Dysfunctional Larynx After (Chemo)Radiotherapy

Archives of Otolaryngology–Head & Neck Surgery, 2012

Objective: To evaluate the functional outcomes after total laryngectomy (TLE) for a dysfunctional... more Objective: To evaluate the functional outcomes after total laryngectomy (TLE) for a dysfunctional larynx in patients with head and neck cancer that is in complete remission after (chemo)radiotherapy.

Research paper thumbnail of Tumor volume as a prognostic factor for local control and overall survival in advanced larynx cancer

The Laryngoscope, Jan 29, 2015

Tumor volume has been postulated to be an important prognostic factor for oncological outcome aft... more Tumor volume has been postulated to be an important prognostic factor for oncological outcome after radiotherapy or chemoradiotherapy. This postulate was retrospectively investigated in a consecutively treated cohort of T3-T4 larynx cancer patients. Retrospective cohort study. For 166 patients with T3-T4 larynx cancer (1999-2008), pretreatment computed tomography and magnetic resonance imaging scans were available for tumor volume delineation. Patients were treated with radiotherapy, chemoradiotherapy, or total laryngectomy with postoperative radiotherapy. Both a dedicated head and neck radiologist and the first author determined all tumor volumes. Statistical analysis was by Kaplan-Meier plots and Cox proportional hazard models. Patients with T3 larynx cancer had significantly smaller tumor volumes than patients with T4 larynx cancer (median = 8.1 cm(3) and 15.8 cm(3) , respectively; P < .0001). In the group treated with total laryngectomy and postoperative radiotherapy, no asso...

Research paper thumbnail of Impact of daily anatomical changes on EPID-based in vivo dosimetry of VMAT treatments of head-and-neck cancer

Radiotherapy and Oncology, 2015

Target dose verification for VMAT treatments of head-and-neck (H&amp;amp;amp;amp;amp;N) cance... more Target dose verification for VMAT treatments of head-and-neck (H&amp;amp;amp;amp;amp;N) cancer using 3D in vivo EPID dosimetry is expected to be affected by daily anatomical changes. By including these anatomical changes through cone-beam CT (CBCT) information, the magnitude of this effect is investigated. For 20 VMAT-treated H&amp;amp;amp;amp;amp;N cancer patients, all plan-CTs (pCTs), 633 CBCTs and 1266 EPID movies were used to compare four dose distributions per fraction: treatment planning system (TPS) calculated dose and EPID reconstructed in vivo dose, both determined using the pCT and using the CBCT. D2, D50 and D98 of the planning target volume (PTV) were determined per dose distribution. When including daily anatomical information, D2, D50 and D98 of the PTV change on average by 0.0±0.4% according to TPS calculations; the standard deviation of the difference between EPID and TPS target dose changes from 2.5% (pCT) to 2.1% (CBCT). Small time trends are seen for both TPS and EPID dose distributions when using the pCT, which disappear when including CBCT information. Daily anatomical changes hardly influence the target dose distribution for H&amp;amp;amp;amp;amp;N VMAT treatments according to TPS recalculations. Including CBCT information in EPID dose reconstructions slightly improves the agreement with TPS calculations.

Research paper thumbnail of Prospective clinical study on long-term swallowing function and voice quality in advanced head and neck cancer patients treated with concurrent chemoradiotherapy and preventive swallowing exercises

European archives of oto-rhino-laryngology : official journal of the European Federation of Oto-Rhino-Laryngological Societies (EUFOS) : affiliated with the German Society for Oto-Rhino-Laryngology - Head and Neck Surgery, Jan 8, 2014

Concurrent chemoradiotherapy (CCRT) for advanced head and neck cancer (HNC) is associated with su... more Concurrent chemoradiotherapy (CCRT) for advanced head and neck cancer (HNC) is associated with substantial early and late side effects, most notably regarding swallowing function, but also regarding voice quality and quality of life (QoL). Despite increased awareness/knowledge on acute dysphagia in HNC survivors, long-term (i.e., beyond 5 years) prospectively collected data on objective and subjective treatment-induced functional outcomes (and their impact on QoL) still are scarce. The objective of this study was the assessment of long-term CCRT-induced results on swallowing function and voice quality in advanced HNC patients. The study was conducted as a randomized controlled trial on preventive swallowing rehabilitation (2006-2008) in a tertiary comprehensive HNC center with twenty-two disease-free and evaluable HNC patients as participants. Multidimensional assessment of functional sequels was performed with videofluoroscopy, mouth opening measurements, Functional Oral Intake Sca...

Research paper thumbnail of T3-T4 laryngeal cancer in The Netherlands Cancer Institute; 10-year results of the consistent application of an organ-preserving/-sacrificing protocol

Head & neck, Jan 31, 2014

Both organ-preserving concurrent (chemo)radiotherapy ((C)RT) and organ-sacrificing surgery (total... more Both organ-preserving concurrent (chemo)radiotherapy ((C)RT) and organ-sacrificing surgery (total laryngectomy) are used for treatment of advanced laryngeal cancer. The purpose of this study was to present the assessment of our treatment protocol for T3 (C)RT and T4 disease (total laryngectomy + postoperative RT). We conducted a retrospective cohort study in 182 consecutive patients (1999-2008). The primary outcome was overall survival (OS) in relation to stage and treatment. One hundred two patients received RT (82.4% T3), 20 patients CRT (60.0% T3), and 60 patients total laryngectomy + RT (91.7% T4). Five-year OS: T3 52%, T4 48%, for RT 50%, for CRT 43%, and for total laryngectomy + RT 52%. Five-year laryngectomy-free interval was 72% after RT, and 83% after CRT. There were no differences in survival according to T classification or treatment modality. Because the majority of T3 laryngeal cancers were treated with (C)RT and the majority of T4 with total laryngectomy + RT, this giv...

Research paper thumbnail of Births, Marriages, and Deaths

Research paper thumbnail of Deformable image registration for adaptive radiation therapy of head and neck cancer: accuracy and precision in the presence of tumor changes

International journal of radiation oncology, biology, physics, 2014

To compare deformable image registration (DIR) accuracy and precision for normal and tumor tissue... more To compare deformable image registration (DIR) accuracy and precision for normal and tumor tissues in head and neck cancer patients during the course of radiation therapy (RT). Thirteen patients with oropharyngeal tumors, who underwent submucosal implantation of small gold markers (average 6, range 4-10) around the tumor and were treated with RT were retrospectively selected. Two observers identified 15 anatomical features (landmarks) representative of normal tissues in the planning computed tomography (pCT) scan and in weekly cone beam CTs (CBCTs). Gold markers were digitally removed after semiautomatic identification in pCTs and CBCTs. Subsequently, landmarks and gold markers on pCT were propagated to CBCTs, using a b-spline-based DIR and, for comparison, rigid registration (RR). To account for observer variability, the pair-wise difference analysis of variance method was applied. DIR accuracy (systematic error) and precision (random error) for landmarks and gold markers were quan...

Research paper thumbnail of The association of treatment delay and prognosis in head and neck squamous cell carcinoma (HNSCC) patients in a Dutch comprehensive cancer center

Research paper thumbnail of QUESTIONS FOR THE COLLEGE COUNCIL

Research paper thumbnail of Total Laryngectomy for a Dysfunctional Larynx After (Chemo)Radiotherapy

Archives of Otolaryngology–Head & Neck Surgery, 2012

Objective: To evaluate the functional outcomes after total laryngectomy (TLE) for a dysfunctional... more Objective: To evaluate the functional outcomes after total laryngectomy (TLE) for a dysfunctional larynx in patients with head and neck cancer that is in complete remission after (chemo)radiotherapy.

Research paper thumbnail of Tumor volume as a prognostic factor for local control and overall survival in advanced larynx cancer

The Laryngoscope, Jan 29, 2015

Tumor volume has been postulated to be an important prognostic factor for oncological outcome aft... more Tumor volume has been postulated to be an important prognostic factor for oncological outcome after radiotherapy or chemoradiotherapy. This postulate was retrospectively investigated in a consecutively treated cohort of T3-T4 larynx cancer patients. Retrospective cohort study. For 166 patients with T3-T4 larynx cancer (1999-2008), pretreatment computed tomography and magnetic resonance imaging scans were available for tumor volume delineation. Patients were treated with radiotherapy, chemoradiotherapy, or total laryngectomy with postoperative radiotherapy. Both a dedicated head and neck radiologist and the first author determined all tumor volumes. Statistical analysis was by Kaplan-Meier plots and Cox proportional hazard models. Patients with T3 larynx cancer had significantly smaller tumor volumes than patients with T4 larynx cancer (median = 8.1 cm(3) and 15.8 cm(3) , respectively; P < .0001). In the group treated with total laryngectomy and postoperative radiotherapy, no asso...