234 Background: A full bladder for prostate radiotherapy treatment limits overall dose to the bladder and displaces bowel from high dose regions. There is currently no clear consensus on optimum bladder volume for prostate radiotherapy. Inconsistent bladder volumes can cause dosimetric uncertainty, distress, treatment delay and negative toxicity outcomes for patients. To identify potential ways to improve bladder filling consistency we retrospectively analysed bladder volume variation over the course of patients’ treatment and its relationship to various patient and treatment factors. Methods: We included all patients treated with 60gy in 20 fractions to the prostate only over a 1-year period. Standard fractionation, palliative, post-operative, and whole pelvis treatment regimens were excluded from our study. Patient, tumour, and treatment characteristics were collected retrospectively. We recorded patient reported IPSS scores that were completed pre and post treatment. Daily bladder volumes were recorded from cone beam CT (CBCT) retrospectively for a subset of 34 patients and included in correlative analyses with various treatment and patient factors. Results: 69 men were included in this study with a mean planning CT bladder volume of 272ml (79-574). Patients were divided into large ( > 180ml) and small subgroups (N = 46 vs 23). Smaller bladders resulted in a greater post treatment IPSS score (10.2 vs 7.7 (p = 0.2)) and greater change in IPSS (+3.3 vs +1.4 (p = 0.23). The variation of daily bladder volumes as measured by the standard deviation was positively associated with planning CT volume (p < 0.05), variation in daily treatment time (p < 0.05) and urinary symptoms (p = 0.29). Greater discordances between planning CT time and mean radiotherapy time resulted in a greater average difference between CBCT bladder volume and planning CT volume (p = 0.16). There were no appreciable seasonal or diurnal associations for all recorded bladder volumes. Conclusions: Smaller bladder volumes at planning CT are associated with increased urinary symptoms whereas larger volumes undergo more daily variation. This data suggests an optimal planning bladder volume of 200-400ml to minimise on treatment variation. This is the first study to demonstrate a relationship between variation in daily treatment times and daily bladder variation. Synchronisation of planning CT time with patient treatment time preference will enable patients to better replicate planning CT bladder volumes. This, along with several other areas for improvement highlighted by this study have formed the basis for a prospective single centre pilot study.
The Inter district Audit of Vascular Surgery project entails the compilation of data on all new vascular patients who are referred, investigated and/or treated in three UK health authorities. The main aim is to create an accurate database containing process/ outcome criteria, which can be interpreted as quality measures and which facilitates review of current practices. Data collection, which began in June 1990 and is scheduled to continue until March 1992, is by a series of proformas. Currently 503 patients are registered on the database, and preliminary results have shown that 28% of initial assessment patients go on to have an arteriogram, 9% are admitted to the hospital immediately and 7% are discharged back to the care of their general practitioner. At follow-up consultation, the patients main presenting symptom had been cured in 38% of cases, but remained unchanged in 27% and had worsened in 5%. The paper concludes by examining the project against some success criteria and recounting some of the practical difficulties of data collection encountered so far.
73 Background: Plasma levels of citrulline, an amino acid, are derived mainly from small bowel enterocytes. Decreased levels occur in a range of bowel conditions and citrulline has been proposed as a biomarker of bowel toxicity in pelvic radiotherapy. In a prospective study, we identify no correlation between plasma citrulline and toxicity in men receiving prostate stereotactic radiotherapy randomized to receive either pelvic nodal irradiation or not. Furthermore, citrulline levels were not significantly different between these two groups. Methods: As part of an approved clinical trial, men with intermediate to high risk prostate cancer were randomised 1:1 to prostate only or prostate + pelvic nodal radiotherapy, delivered with a rectal spacer gel in situ. The prostate and proximal seminal vesicles received 40 Gy in 5 fractions. Those randomised to the pelvic nodal arm also received 25 Gy in 5 fractions to pelvic nodes. Citrulline was measured at 10 points during treatment – consent, before fraction 1, 1 and 24 hours following fraction 1, prior to each fraction 2 – 5 and at 6 weeks’ and 3 months’ follow up. Bowel toxicity was measured by EPIC patient reported scores. Results: 16 men with follow up of at least 3 months (median 9, maximum 18 months) were analysed. Reported toxicity was significantly higher in the prostate and pelvis arm: 5 of 9 men showed a decrease in EPIC bowel domain summary score of 10 points or more compared to 0 of 7 in the prostate-only arm (p = 0.0337, two tailed Fisher’s exact test). No significant correlation between toxicity and citrulline levels was seen, nor did citrulline vary significantly between arms or fall as treatment progressed. Data analysis for a further 8 men already recruited to the study is ongoing. Conclusions: Toxicity was more commonly reported by men randomised to receive pelvic radiotherapy, suggesting that the small bowel irradiated in pelvic fields plays a role in bowel toxicity experienced during stereotactic radiotherapy. Citrulline levels showed no significant correlation with toxicity or radiation dose to small bowel. We propose that citrulline is not a useful biomarker of small bowel toxicity in this setting. Clinical trial information: NCT03253978.
97 Background: Multiple randomized controlled trials (RCTs) have demonstrated the benefit of the addition of androgen deprivation therapy (ADT) to external beam radiotherapy (EBRT) in the treatment of men with localized prostate cancer (PC). Anti-androgens (AA) may have a better toxicity profile than luteinizing hormone-releasing hormone agonists (LHRHa). However, no RCT has directly compared these agents in combination with radical EBRT. We evaluated outcomes for men with localized PC treated with EBRT in conjunction with either LHRHa or AA therapy. Methods: Data from 409 consecutive patients treated in NI with radical EBRT (70-74 Gy/2Gy #) between 2005 and 2009 were reviewed. Baseline and treatment characteristics analysed comprised age at diagnosis, T stage, initial PSA (iPSA), Gleason score, age-adjusted Charlson comorbidity index (aCCI), ADT type and radiation dose. Outcomes included biochemical progression-free survival (bPFS; Phoenix), prostate cancer-specific survival (PCSS) and overall survival (OS). Cox Proportional Hazards model was used for multivariate analysis (MVA). Results: Men receiving LHRHa were significantly more likely to be older and have a higher iPSA. On MVA, factors independently associated with biochemical failure were T stage ≥ 3 and use of AA (p < 0.004 and p < 0.02 respectively). On MVA, the single independent factor for poorer OS was higher aCCI (p < 0.000015). There was a trend towards poorer OS in the LHRHa group (p = 0.087). Conclusions: An aCCI > 4 was the only independent factor for poorer OS. While there was a significantly increased rate of biochemical failure in the AA group, there was a trend towards poorer OS in the LHRHa group. This study suggests that AA may be a reasonable alternative to LHRHa therapy in men with localized PC treated with radical EBRT and ADT. [Table: see text]
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