| 1. |
- Alsadius, David, 1975, et al.
(författare)
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Mean Absorbed Dose to the Anal-Sphincter Region and Fecal Leakage among Irradiated Prostate Cancer Survivors.
- 2012
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Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : Elsevier BV. - 1879-355X .- 0360-3016. ; 84:2
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To supplement previous findings that the absorbed dose of ionizing radiation to the anal sphincter or lower rectum affects the occurrence of fecal leakage among irradiated prostate-cancer survivors. We also wanted to determine whether anatomically defining the anal-sphincter region as the organ at risk could increase the degree of evidence underlying clinical guidelines for restriction doses to eliminate this excess risk. METHODS AND MATERIALS: We identified 985 men irradiated for prostate cancer between 1993 and 2006. In 2008, we assessed long-term gastrointestinal symptoms among these men using a study-specific questionnaire. We restrict the analysis to the 414 men who had been treated with external beam radiation therapy only (no brachytherapy) to a total dose of 70 Gy in 2-Gy daily fractions to the prostate or postoperative prostatic region. On reconstructed original radiation therapy dose plans, we delineated the anal-sphincter region as an organ at risk. RESULTS: We found that the prevalence of long-term fecal leakage at least once per month was strongly correlated with the mean dose to the anal-sphincter region. Examining different dose intervals, we found a large increase at 40 Gy; ≥40 Gy compared with <40 Gy gave a prevalence ratio of 3.8 (95% confidence interval 1.6-8.6). CONCLUSIONS: This long-term study shows that mean absorbed dose to the anal-sphincter region is associated with the occurrence of long-term fecal leakage among irradiated prostate-cancer survivors; delineating the anal-sphincter region separately from the rectum and applying a restriction of a mean dose <40 Gy will, according to our data, reduce the risk considerably.
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| 2. |
- Alsadius, David, 1975, et al.
(författare)
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Patient-reported gastrointestinal symptoms among long-term survivors after radiation therapy for prostate cancer.
- 2014
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Ingår i: Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. - : Elsevier BV. - 1879-0887. ; 112:2, s. 237-243
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Tidskriftsartikel (refereegranskat)abstract
- With modern radiotherapy technology we have the means to substantially reduce late gastrointestinal toxicities after radiation therapy for prostate cancer. However, there is still a lack of knowledge regarding the spectrum of patient-reported gastrointestinal symptoms after such treatment.
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| 3. |
- Alsadius, David, 1975, et al.
(författare)
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Perception of body odor-an overlooked consequence of long-term gastrointestinal and urinary symptoms after radiation therapy for prostate cancer.
- 2013
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Ingår i: Journal of cancer survivorship : research and practice. - : Springer Science and Business Media LLC. - 1932-2267. ; 7:4, s. 652-658
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Tidskriftsartikel (refereegranskat)abstract
- Purpose This study was conducted to investigate the association of long-term gastrointestinal and urinary symptoms with perceived fecal or urine body odor after radiation therapy for prostate cancer and its effect on survivors’ quality of life. Methods We used a study-specific questionnaire to measure the occurrence of long-term gastrointestinal and urinary symptoms, the perception of fecal or urine body odor, and quality of life (QoL) 2 to 14 years after radiation therapy for prostate cancer. The questionnaire was sent to 895 eligible survivors who assessed symptom occurrence and QoL in the previous 6 months. Results We received a filled-in questionnaire from 874 (89 %) men. For the long-term gastrointestinal symptoms, 11/13 were associated with the perception of fecal body odor. For the long-term urinary symptoms, 11/11 were associated with the perception of urine body odor. Men who perceived fecal or urine body odor had a lower quality of life, a lower physical health, and more frequent feelings of depression compared with those who did perceive such body odor. Conclusion Long-term gastrointestinal and urinary symptoms after prostate irradiation are associated with the perception of fecal or urine body odor leading to a reduced quality of life. Implications for cancer survivors Disabling body odor after pelvic irradiation needs to be acknowledged in the clinic. Interventions to prevent long-term symptoms may serve the benefit of avoiding fecal or urine body odor after radiation therapy for prostate cancer.
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| 4. |
- Alsadius, David, 1975, et al.
(författare)
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Tobacco smoking and long-lasting symptoms from the bowel and the anal-sphincter region after radiotherapy for prostate cancer.
- 2011
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Ingår i: Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology. - : Elsevier BV. - 1879-0887.
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND PURPOSE: Tobacco smoking can cause vascular injury, tissue hypoxia and fibrosis as can ionizing radiation. However, we do not know if tobacco smoking increases the risk of long-term side effects after radiotherapy for prostate cancer. METHODS: We identified 985 men treated with radiotherapy for prostate cancer between 1993 and 2006. In 2008, long-lasting symptoms appearing after radiotherapy for prostate cancer were assessed through a study-specific questionnaire as were smoking habits and demographic factors of all these men. In the questionnaire the prostate-cancer survivors were asked to report symptom occurrence the previous six months. RESULTS: We obtained information on tobacco smoking from 836 of the 985 prostate-cancer survivors with a median time to follow-up of six years (range 2-14years). The prevalence ratio of defecation urgency among current smokers compared to never smokers was 1.6 (95% CI 1.2-2.2). Corresponding prevalence ratio for diarrhea was 2.8 (95% CI 1.2-6.5), the sensation of bowel not completely emptied after defecation 2.1 (95% CI 1.3-3.3) and for sudden emptying of all stools into clothing without forewarning 4.7 (95% CI 2.3-9.7). CONCLUSION: Tobacco smoking among prostate-cancer survivors treated with radiotherapy increases the risk of certain long-lasting symptoms from the bowel and anal-sphincter region.
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| 5. |
- Braide, Karin, et al.
(författare)
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Salvage radiation therapy in prostate cancer: relationship between rectal dose and long-term, self-reported rectal bleeding
- 2021
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Ingår i: Clinical & Translational Oncology. - : Springer Science and Business Media LLC. - 1699-048X .- 1699-3055. ; 23:2, s. 397-404
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Tidskriftsartikel (refereegranskat)abstract
- Purpose To quantify the relationship between the rectal dose distribution and the prevalence of self-reported rectal bleeding among men treated with salvage radiotherapy (ST) delivered by three-dimensional conformal radiotherapy (3DCRT) for prostate cancer. To use this relationship to estimate the risk of rectal bleeding for a contemporary cohort of patients treated with volumetric modulated arc therapy (VMAT) ST. Methods and patients Rectal bleeding of any grade was reported by 56 (22%) of 255 men in a PROM-survey at a median follow-up of 6.7 years after 3DCRT ST. Treatment plan data were extracted and dose-response relationships for the rectal volumes receiving at least 35 Gy (V-35Gy) or 63 Gy (V-63Gy) were calculated with logistic regression. These relationships were used to estimate the risk of rectal bleeding for a cohort of 253 patients treated with VMAT ST. Results In the dose-response analysis of patients in the 3DCRT ST cohort, both rectal V(35Gy)and V(63Gy)were statistically significant parameters in univariable analysis (p = 0.005 and 0.003, respectively). For the dose-response models using either rectal V(35Gy)or V-63Gy, the average calculated risk of rectal bleeding was 14% among men treated with VMAT ST compared to a reported prevalence of 22% for men treated with 3DCRT ST. Conclusions We identified dose-response relationships between the rectal dose distribution and the risk of self-reported rectal bleeding of any grade in a long-term perspective for men treated with 3DCRT ST. Furthermore, VMAT ST may have the potential to decrease the prevalence of late rectal bleeding.
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| 6. |
- Cervino, L. I., et al.
(författare)
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An in vitro study for the dosimetric and radiobiological validation of respiratory gating in conventional and hypofractionated radiotherapy of the lung: effect of dose, dose rate, and breathing pattern
- 2019
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 64:13
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Tidskriftsartikel (refereegranskat)abstract
- Stereotactic body radiotherapy (SBRT) of the lung has become a standard of care for early-stage inoperable non-small cell lung cancer (NSCLC). A common strategy to manage respiratory motion is gating, which inevitably results in an increase in treatment time, especially in irregularly-breathing patients. Flattening-filter free (FFF) beams allow for delivery of the treatment at a higher dose rate, therefore counteracting the lengthened treatment time due to frequent interruption of the beam during gated radiotherapy. In this study, we perform our in vitro evaluation of the dosimetric and radiobiological effect of gated lung SBRT with simultaneous integrated boost (SIB) using both flattened and FFF beams. A moving thorax-shaped phantom with inserts and applicators was used for simulation, planning, gated treatment delivery measurements and in vitro tests. The effects of gating window, dose rate, and breathing pattern were evaluated. Planned doses represented a typical conventional fractionation, 200 cGy per fraction with SIB to 240 cGy, flattened beam only, and SBRT, 800 cGy with SIB to 900 cGy, flattened and FFF beams. Ideal, as well as regular and irregular patient-specific breathing patterns with and without gating were used. A survival assay for lung adenocarcinoma A549 cell line was performed. Delivered dose was within 6% for locations planned to receive 200 and 800 cGy and within 4% for SIB locations. Time between first beam-on and last beam-off varied from approximately 1.5 min for conventional fractionation, 200/240 cGy, to 10.5 min for gated SBRT, 800/900 cGy doses, flattened beam and irregular breathing motion pattern. With FFF beams dose delivery time was shorter by a factor of 2-3, depending on the gating window and breathing pattern. We have found that, for the most part, survival depended on dose and not on dose rate, gating window, or breathing regularity.
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| 7. |
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| 8. |
- Moiseenko, Vitali, et al.
(författare)
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A Primer on Dose-Response Data Modeling in Radiation Therapy.
- 2021
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Ingår i: International journal of radiation oncology, biology, physics. - : Elsevier BV. - 1879-355X .- 0360-3016. ; 110:1, s. 11-20
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Tidskriftsartikel (refereegranskat)abstract
- An overview of common approaches used to assess a dose response for radiation therapy-associated endpoints is presented, using lung toxicity data sets analyzed as a part of the High Dose per Fraction, Hypofractionated Treatment Effects in the Clinic effort as an example. Each component presented (eg, data-driven analysis, dose-response analysis, and calculating uncertainties on model prediction) is addressed using established approaches. Specifically, the maximum likelihood method was used to calculate best parameter values of the commonly used logistic model, the profile-likelihood to calculate confidence intervals on model parameters, and the likelihood ratio to determine whether the observed data fit is statistically significant. The bootstrap method was used to calculate confidence intervals for model predictions. Correlated behavior of model parameters and implication for interpreting dose response are discussed.
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| 9. |
- Mövik, Louise, 1993, et al.
(författare)
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Impact of delineation errors on the estimated organ at risk dose and of dose errors on the normal tissue complication probability model
- 2023
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Ingår i: Medical Physics. - : Wiley. - 0094-2405 .- 2473-4209. ; 50:3, s. 1879-1892
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Tidskriftsartikel (refereegranskat)abstract
- Background: Normal tissue complication probability (NTCP) models are often based on doses retrieved from delineated volumes. For retrospective dose-response studies focusing on organs that have not been delineated historically, automatic segmentation might be considered. However, automatic segmentation risks generating considerable delineation errors and knowledge regarding how these errors impact the estimated organ dose is important. Furthermore, organ-at-risk (OAR) dose uncertainties cannot be eliminated and might affect the resulting NTCP model. Therefore, it is also of interest to study how OAR dose errors impact the NTCP modeling results. Purpose: To investigate how random delineation errors of the proximal bronchial tree, heart, and esophagus impact the estimated OAR dose, and to investigate how random errors in the doses used for dose-response modeling affect the estimated NTCPs. Methods: We investigated the impact of random delineation errors on the estimated OAR dose using the treatment plans of 39 patients treated with conventionally fractionated radiation therapy of non-small-cell lung cancer. Study-specific reference structures were defined by manually contouring the proximal bronchial tree, heart and esophagus. For each patient and organ, 120 reshaped structures were created by introducing random shifts and margins to the entire reference structure. The mean and near-maximum dose to the reference and reshaped structures were compared. In a separate investigation, the impact of random dose errors on the NTCP model was studied performing dose-response modeling with study sets containing treatment outcomes and OAR doses with and without introduced errors. Universal patient populations with defined population risks, dose-response relationships and distributions of OAR doses were used as ground truth. From such a universal population, we randomly sampled data sets consisting of OAR dose and treatment outcome into reference populations. Study sets of different sizes were created by repeatedly introducing errors to the OAR doses of each reference population. The NTCP models generated with dose errors were compared to the reference NTCP model of the corresponding reference population. Results: A total of 14 040 reshaped structures with random delineation errors were created. The delineation errors resulted in systematic mean dose errors of less than 1% of the prescribed dose (PD). Mean dose differences above 15% of PD and near-maximum doses differences above 25% of PD were observed for 211 and 457 reshaped structures, respectively. Introducing random errors to OAR doses used for dose-response modeling resulted in systematic underestimations of the median NTCP. For all investigated scenarios, the median differences in NTCP were within 0.1 percentage points (p.p.) when comparing different study sizes. Conclusions: Introducing random delineation errors to the proximal bronchial tree, heart and esophagus resulted in mean dose and near-maximum dose differences above 15% and 25% of PD, respectively. We did not observe an association between the dose level and the magnitude of the dose errors. For the scenarios investigated in this study, introducing random errors to OAR doses used for dose-response modeling resulted in systematic underestimations of the median NTCP for reference risks higher than the universal population risk. The median NTCP underestimation was similar for different study sizes, all within 0.1 p.p.
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| 10. |
- Olsson, C. E., et al.
(författare)
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Feasibility of Mastication-Structure-Sparing Radiotherapy for Head and Neck Cancer
- 2021
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Ingår i: International journal of radiation oncology, biology, physics. - : Elsevier BV. - 1879-355X .- 0360-3016. ; 111:3
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE/OBJECTIVE(S): Although radiation-induced side-effects affecting mastication functionality have been studied in head and neck cancer (HNC) radiotherapy (RT), dose constraints for the associated structures are rarely included during treatment plan optimization. Previous research has identified several radiation dose relationships with mean dose thresholds around 30-40 Gy for masseter muscles, 40-50 Gy for pterygoid muscles, and 15-60 Gy for temporomandibular joint (TMJ) relating to a 10% trismus risk post RT. The purpose of this work was to use a multi-criteria optimization (MCO) approach to investigate to what extent doses to these structures can be lowered without violating existing clinical treatment goals in inverse planning of HNC RT. MATERIALS/METHODS: This exploratory treatment planning study used data from 22 HNC patients treated to 68 Gy without mastication-structure-sparing intent in 2017-2019 at one institute in Sweden. Original volumetric-modulated arc therapy (VMAT) plans were re-activated in the treatment planning system and masseter muscles, pterygoid muscles (medial and lateral), and TMJ were consistently delineated according to a previously reported delineation manual4. Re-planning was done using the MCO function of the treatment planning system with the resulting dose distribution normalized to match the clinical target volume (CTV T) mean dose of the clinical treatment plan. Dose differences between MCO and clinical plans were not allowed to exceed 2 Gy for any original clinical treatment goal unless tolerance doses had been substantially exceeded in the clinical treatment plan. To what extent dose to mastication structures could be lowered without violating existing clinical treatment goals were quantified by group and by patient. RESULTS: Altogether, there were 334 clinical treatment goals in the clinical treatment plans (median=15, range: 7-24 per patient, depending on tumor location), which easily could be met in the corresponding MCO plans. Mean doses to the mastication structures were in most cases below proposed tolerance doses in the clinical plan but could on average be further reduced between 3-5 Gy in the MCO plans (Table). Of the 25/88 patient reductions below 5 Gy (28%), 18/25 (72%) were for the masseter (n=8) and medial pterygoid (n=10) muscles. CONCLUSION: With modern RT, it seems possible to reduce the dose to mastication structures below proposed trismus dose tolerance thresholds for most HNC patients without violating clinical treatment goals. Focusing on masseter and medial pterygoid muscle doses may prove to give the largest benefit in individual cases. Copyright © 2021. Published by Elsevier Inc.
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