[en] Background and purpose: In muscle-invasive bladder cancer there is an urgent need to identify relatively non-toxic radiosensitising agents for use in elderly patients. Histone deacetylase inhibitors radiosensitise tumour cells but not normal cells in vitro and variously downregulate DNA damage signalling, homologous recombination (HR) and non-homologous end-joining (NHEJ) repair proteins. We investigated panobinostat (PAN) as a potential radiosensitiser in bladder cancer cells. Materials and methods: Clonogenic assays were performed in RT112 bladder cancer cells, and RT112 cells stably knocked down for RAD51 or Ku80 by shRNAi. Resolution of γH2AX foci was determined by immunofluorescence confocal microscopy, cell cycle progression by FACS analysis and protein expression by western blotting. Results: PAN had a greater radiosensitising effect in Ku80KD than RT112 or RAD51KD cells; enhancement ratios 1.35 for Ku80KD at 10 nM (IC₂₀ for Ku80KD) and 1.31 for RT112 and RAD51KD at 25 nM (IC₄₀ for both). PAN downregulated MRE11, NBS1 and RAD51, but not Ku70 and Ku80, increased γH2AX foci formation in a dose-dependent manner and delayed γH2AX foci repair after ionising radiation. Conclusions: PAN acts as a radiosensitiser in bladder cancer cell lines, and appears to target HR rather than NHEJ. As muscle-invasive bladder tumours have reduced Ku-DNA binding, PAN could be particularly useful as a radiosensitiser in bladder cancer

[en] Purpose: To study the relationship between the severity of late reactions to radiotherapy in breast cancer patients, and the extent of residual radiation-induced DNA damage, using a rapid assay of keratinocytes obtained directly from skin biopsies. Methods and Materials: A review was made of 32 patients with breast cancer, treated uniformly by radiotherapy between 1983 and 1988, following breast-conserving surgery. Their late radiotherapy reactions were scored (9-14 years post-radiotherapy) using a modified LENT SOMA scale, and a 5-mm buttock skin punch biopsy was obtained. Intact skin was irradiated at room temperature, and after allowing 24 h for repair, the tissue was disaggregated and the cells processed for pulsed field gel electrophoresis (PFGE). Residual DNA damage was expressed as the fraction of DNA released (FDR) following 150 Gy. Results: Studies using flow cytometry on disaggregated breast skin showed that over 90% of the cells were keratinocytes. The PFGE assay was robust with low background FDRs in unirradiated skin samples (mean 3.2%) and a wide range of FDRs following irradiation from 11.5% to 26.6%. No correlation was found between the FDR at 150 Gy (FDR 150) and any of the late reaction scores or retrospective acute reaction scores. There was, however, a borderline significant correlation for family history and FDR 150 (p = 0.059). Conclusion: Rapid measurement of residual DNA damage in irradiated differentiated keratinocytes, the predominant cell population in skin biopsies, showed no correlation with the severity of symptomatic early or documented late reactions in a retrospectively studied group of 32 breast cancer patients

[en] Purpose: To study the relationship between residual DNA damage and clonogenic measurements of radiosensitivity in fibroblasts from pretreatment cervix cancer patients. Methods and Materials: Early passage vaginal fibroblasts from nine preradiotherapy cervix cancer patients and two radiosensitive skin fibroblast cell strains were studied. Cell survival was measured by clonogenic assay following both high and low dose rate irradiation. Residual DNA damage was measured using pulsed-field gel electrophoresis (PFGE) after irradiating radiolabeled, plateau-phase cells at 37 deg. C and allowing 24 h for repair. DNA damage was expressed both in terms of the residual damage slope (fitted to data from 60 to 150 Gy) and the fraction of activity released (FAR) following 150 Gy. Results: The surviving fraction at 2 Gy (SF₂) values after high dose rate irradiation for the vaginal fibroblasts ranged from 0.15 to 0.32 (a 2.2-fold difference). When the two radiosensitive cell strains were included, residual damage, expressed as the residual damage slope, correlated with α (r = 0.82, p = 0.002), D bar (r = -0.91, p < 0.001) and SF₂ (p = -0.79, p = 0.004), and when the vaginal fibroblasts alone were studied, the residual damage slope again correlated with clonogenic survival, although less strongly [α (r 0.66, p = 0.053), D bar (r = -0.83, p = 0.006), and SF₂ (r = -0.63, p 0.07)]. Within the group of vaginal fibroblasts there was a 4.0-fold difference in residual DNA damage slope. When residual damage was expressed as FAR at 150Gy, then for all cell strains the correlations were α: r 0.78, p 0.004, D bar: r = -0.86, p = 0.001, and SF₂: r = -0.78, p = 0.004, and for the vaginal fibroblast strains alone the correlations were α: r = 0.60, p = 0.088, D bar: r = -0.75, p = 0.02, and SF₂: r = 0.62, p = 0.077. Conclusion: This study confirms previous findings that residual DNA damage correlates with clonogenic survival in fibroblasts. In addition, it demonstrates a correlation for fibroblasts from pretreatment cervix cancer patients demonstrating a relatively small range of SF₂ values

[en] Purpose: To conduct a retrospective analysis within a large university teaching hospital, comparing outcomes between patients receiving either radical surgery or radiotherapy as curative treatment for bladder cancer. Patients and Methods: Between March 1996 and December 2000, 169 patients were treated radically for muscle-invasive bladder cancer. Data were collected from patient notes. Statistical analyses were performed using Kaplan-Meier methods and Cox proportional hazards regression analysis to compare radiotherapy and surgical outcome data. Results: There was no difference in overall, cause-specific, and distant recurrence-free survival at 5 years between the two groups, despite the radiotherapy group being older (median age, 75.3 years vs. 68.2 years). There were 31 local bladder recurrences in the radiotherapy group (24 solitary), but there was no significant difference in distant recurrence-free survival. In a more recent (2002-2006) cohort, the median age of radiotherapy patients but not the cystectomy patients was higher than in the 1996-2000 cohort (78.4 years vs. 75.3 years for radiotherapy and 67.9 years vs. 68.2 years for surgery). Conclusions: Although the patients undergoing radical cystectomy were significantly younger than the radiotherapy patients, treatment modality did not influence survival. Bladder cancer patients are an increasingly elderly group. Radical radiotherapy is a viable treatment option for these patients, with the advantage of organ preservation