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- Al-Ubaidi, Firas L. T., et al.
(författare)
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CASTRATION THERAPY OF PROSTATE CANCER RESULTS IN DOWNREGULATION OF HIF-1 alpha LEVELS
- 2012
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Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : Elsevier BV. - 0360-3016 .- 1879-355X. ; 82:3, s. 1243-1248
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Tidskriftsartikel (refereegranskat)abstract
- Background and Purpose: Neoadjuvant androgen deprivation in combination with radiotherapy of prostate cancer is used to improve radioresponsiveness and local tumor control. Currently, the underlying mechanism is not well understood. Because hypoxia causes resistance to radiotherapy, we wanted to test whether castration affects the degree of hypoxia in prostate cancer. Methods and Materials: In 14 patients with locally advanced prostate cancer, six to 12 prostatic needle core biopsy specimens were taken prior to castration therapy. Bilateral orchidectomy was performed in 7 patients, and 7 were treated with a GnRH-agonist (leuprorelin). After castrationm two to four prostatic core biopsy specimens were taken, and the level of hypoxia-inducible factor-1 alpha (HIF-1 alpha) in cancer was determined by immunofluorescence. Results: Among biopsy specimens taken before castration, strong HIF-1 alpha expression (mean intensity above 30) was shown in 5 patients, weak expression (mean intensity 10-30) in 3 patients, and background levels of HIF-1 alpha (mean intensity 0-10) in 6 patients. Downregulation of HIF-1 alpha expression after castration was observed in all 5 patients with strong HIF-1 alpha precastration expression. HIF-1 alpha expression was also reduced in 2 of 3 patients with weak HIF-1 alpha precastration expression. Conclusions: Our data suggest that neoadjuvant castration decreases tumor cell hypoxia in prostate cancer, which may explain increased radiosensitivity after castration.
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- 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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- Brændengen, Morten, et al.
(författare)
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Delineation of gross tumor volume (GTV) for radiation treatment planning of locally advanced rectal cancer using information from MRI or FDG-PET/CT : a prospective study
- 2011
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Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : Elsevier BV. - 0360-3016 .- 1879-355X. ; 81:4, s. e439-e445
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE:Accurate delineation of target volumes is important to maximize radiation dose to the tumor and minimize it to nontumor tissue. Computed tomography (CT) and magnetic resonance imaging (MRI) are standard imaging modalities in rectal cancer. The aim was to explore whether functional imaging with F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET), combined with CT (FDG-PET/CT) gives additional information to standard pretreatment evaluation and changes the shape and size of the gross tumor volume (GTV).METHODS AND MATERIALS:From 2007 to 2009, 77 consecutive patients with locally advanced rectal cancer were prospectively screened for inclusion in the study at two university hospitals in Sweden, and 68 patients were eligible. Standard GTV was delineated using information from clinical examination, CT, and MRI (GTV-MRI). Thereafter, a GTV-PET was defined in the fused PET-CT, and the target volume delineations were compared for total volume, overlap, and mismatch. Pathologic uptake suspect of metastases was also registered.RESULTS:The median volume of GTV-MRI was larger than that of GTV-PET: 111 cm3 vs. 87 cm3 (p < 0.001). In many cases, the GTV-MRI contained the GTV defined on the PET/CT images as subvolumes, but when a GTV total was calculated after the addition of GTV-PET to GTV-MRI, the volume increased, with median 11% (range, 0.5–72%). New lesions were seen in 15% of the patients for whom PET/CT was used.CONCLUSIONS:FDG-PET/CT facilitates and adds important information to the standard delineation procedure of locally advanced rectal cancer, mostly resulting in a smaller GTV, but a larger total GTV using the union of GTV-MRI and GTV-PET. New lesions were sometimes seen, potentially changing the treatment strategy.
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- Braendengen, Morten, et al.
(författare)
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Late patient-reported toxicity after preoperative radiotherapy or chemoradiotherapy in nonresectable rectal cancer : Results from a randomized phase III study
- 2011
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Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : Elsevier BV. - 0360-3016 .- 1879-355X. ; 81:4, s. 1017-1024
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Preoperative chemoradiotherapy (CRT) is superior to radiotherapy (RT) in locally advanced rectal cancer, but the survival gain is limited. Late toxicity is, therefore, important. The aim was to compare late bowel, urinary, and sexual functions after CRT or RT. Methods and Materials: Patients (N = 207) with nonresectable rectal cancer were randomized to preoperative CRT or RT (2 Gy x 25 +/- 5-fluorouracil/leucovorin). Extended surgery was often required. Self-reported late toxicity was scored according to the LENT SOMA criteria in a structured telephone interview and with questionnaires European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ-C30), International Index of Erectile Function (IIEF), and sexual function -vaginal changes questionnaire (SVQ). Results: Of the 105 patients alive in Norway and Sweden after 4 to 12 years of follow-up, 78 (74%) responded. More patients in the CRT group had received a stoma (73% vs. 52%, p = 0.09). Most patients without a stoma (7 of 12 in CRT group and 9 of 16 in RT group) had incontinence for liquid stools or gas. No stoma and good anal function were seen in 5 patients (11%) in the CRT group and in 11 (30%) in the RT group (p = 0.046). Of 44 patients in the CRT group, 12 (28%) had had bowel obstruction compared with 5 of 33 (15%) in the RT group (p = 0.27). One-quarter of the patients reported urinary incontinence. The majority of men had severe erectile dysfunction. Few women reported sexual activity during the previous month. However, the majority did not have concerns about their sex life. Conclusions: Fecal incontinence and erectile dysfunction are frequent after combined treatment for locally advanced rectal cancer. There was a clear tendency for the problems to be more common after CRT than after RT.
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- Daşu, Alexandru, et al.
(författare)
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Secondary malignancies from prostate cancer radiation treatment : a risk analysis of the influence of target margins and fractionation patterns
- 2011
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Ingår i: International Journal of Radiation Oncology, Biology, Physics. - : Elsevier BV. - 0360-3016 .- 1879-355X. ; 79:3, s. 738-746
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: This study explores the implications for cancer induction of treatment details such as fractionation, planning target volume (PTV) definition, and interpatient variations, which are relevant for the radiation treatment of prostate carcinomas.METHODS AND MATERIALS: Treatment planning data from 100 patients have been analyzed with a risk model based on the United Nations Scientific Committee on the Effects of Atomic Radiation competition model. The risk model can account for dose heterogeneity and fractionation effects characteristic for modern radiotherapy. Biologically relevant parameters from clinical and experimental data have been used with the model.RESULTS: The results suggested that changes in prescribed dose could lead to a modification of the risks for individual organs surrounding the clinical target volume (CTV) but that the total risk appears to be less affected by changes in the target dose. Larger differences are observed for modifications of the margins between the CTV and the PTV because these have direct impact onto the dose level and dose heterogeneity in the healthy tissues surrounding the CTV. Interpatient anatomic variations also have to be taken into consideration for studies of the risk for cancer induction from radiotherapy.CONCLUSIONS: The results have shown the complex interplay between the risk for secondary malignancies, the details of the treatment delivery, and the patient heterogeneity that may influence comparisons between the long-term effects of various treatment techniques. Nevertheless, absolute risk levels seem very small and comparable to mortality risks from surgical interventions, thus supporting the robustness of radiation therapy as a successful treatment modality for prostate carcinomas.
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