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| 183. |
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| 184. |
- Nenoff, Lena, et al.
(författare)
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Daily Adaptive Proton Therapy : Is it Appropriate to Use Analytical Dose Calculations for Plan Adaption?
- 2020
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Ingår i: International Journal of Radiation Oncology Biology Physics. - : Elsevier BV. - 0360-3016. ; 107:4, s. 747-755
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The accuracy of analytical dose calculations (ADC) and dose uncertainties resulting from anatomical changes are both limiting factors in proton therapy. For the latter, rapid plan adaption is necessary; for the former, Monte Carlo (MC) approaches are increasingly recommended. These, however, are inherently slower than analytical approaches, potentially limiting the ability to rapidly adapt plans. Here, we compare the clinical relevance of uncertainties resulting from both. Methods and Materials: Five patients with non-small cell lung cancer with up to 9 computed tomography (CT) scans acquired during treatment and five paranasal (head and neck) patients with 10 simulated anatomical changes (sinus filling) were analyzed. On the initial planning CT scans, treatment plans were optimized and calculated using an ADC and then recalculated with MC. Additionally, all plans were recalculated (non-adapted) and reoptimized (adapted) on each repeated CT using the same ADC as for the initial plan, and the resulting dose distributions were compared. Results: When comparing analytical and MC calculations in the initial treatment plan and averaged over all patients, 94.2% (non-small cell lung cancer) and 98.5% (head and neck) of voxels had differences <±5%, and only minor differences in clinical target volume (CTV) V95 (average <2%) were observed. In contrast, when recalculating nominal plans on the repeat (anatomically changed) CT scans, CTV V95 degraded by up to 34%. Plan adaption, however, restored CTV V95 differences between adapted and nominal plans to <0.5%. Adapted organ-at-risk doses remained the same or improved. Conclusions: Dose degradations caused by anatomic changes are substantially larger than uncertainties introduced by the use of analytical instead of MC dose calculations. Thus, if the use of analytical calculations can enable more rapid and efficient plan adaption than MC approaches, they can and should be used for plan adaption for these patient groups.
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| 185. |
- Nielsen, Steffen, et al.
(författare)
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Comparison of Coding Transcriptomes in Fibroblasts Irradiated With Low and High LET Proton Beams and Cobalt-60 Photons
- 2019
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Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : Elsevier BV. - 0360-3016 .- 1879-355X. ; 103:5, s. 1203-1211
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To identify differential cellular responses after proton and photon irradiation by comparing transcriptomes of primary fibroblasts irradiated with either radiation type. Methods and Materials: A panel of primary dermal fibroblast cultures was irradiated with low and higher linear energy transfer (LET) proton beams. Cobalt-60 photon irradiation was used as reference. Dose was delivered in 3 fractions of 3.5 Gy (relative biological effectiveness) using a relative biological effectiveness of 1.1 for proton doses. Cells were harvested 2 hours after the final fraction was delivered, and RNA was purified. RNA sequencing was performed using Illumina NextSeq 500 with high-output kit. The edgeR package in R was used for differential gene expression analysis. Results: Pairwise comparisons of the transcriptomes in the 3 treatment groups showed that there were 84 and 56 differentially expressed genes in the low LET group compared with the Cobalt-60 group and the higher LET group, respectively. The higher LET proton group and the Cobalt-60 group had the most distinct transcriptome profiles, with 725 differentially regulated genes. Differentially regulated canonical pathways and various regulatory factors involved in regulation of biological mechanisms such as inflammation, carcinogenesis, and cell cycle control were identified. Conclusions: Inflammatory regulators associated with the development of normal tissue complications and malignant transformation factors seem to be differentially regulated by higher LET proton and Cobalt-60 photon irradiation. The reported transcriptome differences could therefore influence the progression of adverse effects and the risk of developing secondary cancers.
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| 186. |
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| 187. |
- Nilsson, Per J, et al.
(författare)
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Epidermoid anal cancer : a review of a population-based series of 308 consecutive patients treated according to prospective protocols
- 2005
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Ingår i: International Journal of Radiation Oncology, Biology, Physics. - New York, USA : Elsevier. - 0360-3016 .- 1879-355X. ; 61, s. 92-102
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Forskningsöversikt (refereegranskat)abstract
- Purpose: The primary therapy in epidermoid anal cancer is radiotherapy, generally with chemotherapy. The use of neoadjuvant chemotherapy has been infrequently reported in the literature. This study presents results from a large population-based series and provides comparisons between different treatments.Methods and materials: Between 1985 and 2000, 308 patients with invasive epidermoid anal cancer were diagnosed in the Stockholm Health Care Region. Treatment was given according to defined protocols. External beam radiotherapy alone or with concomitant bleomycin and neoadjuvant chemotherapy followed by radiotherapy alone were the primary treatments. Radical surgery was reserved for poor responders or recurrences. Data were reviewed with regard to treatment, outcome, and prognostic factors.Results: Among the 276 patients (90%) treated with curative intent, 264 (96%) received treatment in accordance with the protocols. The overall 5-year survival rate was 68%. Among the 142 patients with locally advanced tumors (T > or =4 cm or N+), patients treated with neoadjuvant platinum-based chemotherapy (n = 91) had significantly better complete response rates compared with patients treated with radiotherapy with or without bleomycin (n = 51) (92% vs. 76%, p < 0.01). A significantly increased overall 5-year survival rate was also found among patients receiving neoadjuvant therapy (63% vs. 44%, p < 0.05).Conclusion: Structured treatment protocols result in favorable outcome on a population level. The results further suggest a significant therapeutic gain from including neoadjuvant chemotherapy in the treatment of locally advanced anal cancer.
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| 188. |
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| 189. |
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| 190. |
- Olsson, Caroline, 1970, et al.
(författare)
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A Systematic Post-QUANTEC Review of Tolerance Doses for Late Toxicity After Prostate Cancer Radiation Therapy
- 2018
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Ingår i: International Journal of Radiation Oncology Biology Physics. - : Elsevier BV. - 0360-3016. ; 102:5, s. 1514-1532
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The aims of this study were to systematically review tolerance doses for late distinct gastrointestinal (GI), genitourinary (GU), and sexual dysfunction (SD) symptoms after external beam radiation therapy (EBRT) alone and treatments involving brachytherapy (BT) for prostate cancer after Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) and ultimately to perform quantitative syntheses of identified dose/volume tolerances represented by dose-volume histogram (DVH) thresholds, that is, statistically significant (P ≤.05) cutoff points between symptomatic and asymptomatic patients in a certain study. Methods and Materials: PubMed was scrutinized for full-text articles in English after QUANTEC (January 1, 2010). The inclusion criteria were randomized controlled trials, case-control studies, or cohort studies with tolerance doses for late distinct symptoms ≥3 months after primary radiation therapy for prostate cancer (N > 30). All DVH thresholds were converted into equivalent doses in 2-Gy fractions (EQD2α/β) and were fitted with a linear or linear-quadratic function (goodness of fit, R2). The review was registered on PROSPERO (CRD42016042464). Results: From 33 identified studies, which included 36 to 746 patients per symptom domain, the majority of dose/volume tolerances were derived for GI toxicity after EBRT alone (GI, 97 thresholds; GU, 8 thresholds; SD, 1 threshold). For 5 symptoms (defecation urgency, diarrhea, fecal incontinence, proctitis, and rectal bleeding), relationships between dose/volume tolerances across studies (R2 = 0.93 [0.82-1.00]), and across symptoms, leading to a curve for overall GI toxicity (R2 = 0.98), could be determined. For these symptoms, mainly rectal thresholds were found throughout low and high doses (10 Gy ≤ equivalent dose in 2-Gy fractions using α/β = 3Gy (EQD23) ≤ 50 Gy and 55 Gy ≤ EQD23 ≤ 78 Gy, respectively). For BT with or without EBRT, dose/volume tolerances were also mainly identified for GI toxicity (GI, 14 thresholds; GU, 4 thresholds; SD, 2 thresholds) with the largest number of DVH thresholds concerning rectal bleeding (5 thresholds). Conclusions: Updated dose/volume tolerances after QUANTEC were found for 17 GI, GU, or SD symptoms. A DVH curve described the relationship between dose/volume tolerances across 5 GI symptoms after EBRT alone. Restricting treatments for EBRT alone using the lower boundaries of this curve is likely to limit overall GI toxicity, but this should be explored prospectively. Dose/volume tolerances for GU and SD toxicity after EBRT alone and after BT with or without EBRT were scarce and support further research including data-sharing initiatives to untangle the dose/volume relationships for these symptoms. © 2018 Elsevier Inc.
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