TFF3 is a promising marker for Barrett's oesophagus screening since it is expressed at the luminal surface of Barrett's oesophagus but not in adjacent tissue types and may be applied to a non-endoscopic screening device.

a b s t r a c tBackground and purpose: Stereotactic ablative body radiotherapy for lung plans requires 4DCT. Most radiotherapy centres use this to determine an internal target volume (ITV), despite studies suggesting that planning on a mid-ventilation (Mid-V) phase can reduce target volumes. The purpose of this study is two-fold: to determine whether the Mid-V approach provides adequate coverage and to discuss methods to enable the Mid-V approach to be applied more widely. Method: 4D scans of 79 patients were outlined on every phase. The mid-V phase was identified. Margins were determined from the range of motion, and plans generated with a 55 Gy prescription. A grid-based method was used to get the probability of tumour coverage in the presence of systematic and random uncertainties, with and without blurring for breathing motion. Results: For the Mid-V plans with the margins calculated from the van-Herk formula, after blurring doses for breathing, the coverage (dose covering 95% of the CTV 95% of the time) was greater than for plans with isotropic 5 mm margins uncorrected for breathing (58.2 Gy v 57.3 Gy). Similar results were obtained for a linear margin chosen as 0.15 of the breathing range. Deformable contour propagation in a commercial outlining system (ProSoma) identified the same mid-V phase in the majority of cases. Conclusion: Our results confirm that a mid-V approach can be used to reduce the PTV size, with no loss of tumour coverage. We propose the use of a simplified margin formula equal to the margin ignoring breathing plus 0.15 of the range of motion.

e17610 Background: External Beam radiotherapy is a standard treatment for patients with intermediate risk localised prostate cancer. Commonly the radiotherapy plan is delivered in two phases with adequate margins, the first phase to the prostate and seminal vesicles and the second phase to the prostate alone. The two phases can be delivered by intensity modulated radiotherapy as a sequential or concomitant treatment. We compared the toxicities and clinical outcomes of patients who received radiotherapy either as sequential or as concomitant treatment. Methods: Two hundred and twenty five consecutive patients with intermediate risk prostate cancer were included in the study. The patients who had sequential treatment received 60 Gy in 30 fractions to the prostate and seminal vesicles,, while patients who had concomitant treatment received 60 Gy in 37 fractions. All patients received 74 Gy in 37 fractions to the prostate. The Genitourinary (GU) and Gastrointestinal (GI) toxicity data and outcomes in terms of biochemical progression free survival were compared. Results: One hundred eighty patients received sequential radiotherapy, while forty five patients received concomitant radiotherapy. Acute GI toxicity was significantly less in the patients who received concomitant radiotherapy, during weeks four(p = 0.03), six(p = 0.03) and eight(p = 0.06) of treatment, compared to patients who receive sequential radiotherapy. Acute GU toxicities were similar in both groups of patients during treatment. Late GU and GI toxicity at 1 year and 2 years were similar. 3 year biochemical Progression free survival was 90 % for patients who received either sequential compared to 75 % for patients who received concomitant radiotherapy, though not statistically significant (log rank p value = 0.173). Conclusions: Concomitant radiotherapy to prostate and seminal vesicles resulted in lower acute gastrointestinal toxicity compared to sequential radiotherapy to the prostate and seminal vesicles as two phases. The genitourinary and late toxicities were similar. Biochemical progression free survival for patients who received concomitant radiotherapy treatment, could however be inferior to sequential treatment, probably due to the lower dose per fraction to the seminal vesicles and margins.

No abstract