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Follistatin is a potent regulator of the inflammatory response and binds to and inhibits activin A action. Activin A is a member of the TGFβ protein superfamily which has regulatory roles in the inflammatory response and in the fibrotic process. Fibrosis can occur following cell injury and cell death induced by agents such as ionizing radiation (IR). IR is used to treat cancer and marked fibrotic response is a normal tissue (non-tumour) consequence in a fraction of patients under the current dose regimes. The discovery and development of a therapeutic to abate fibrosis in these radiosensitive patients would be a major advance for cancer radiotherapy. Likewise, prediction of which patients are susceptible to fibrosis would enable individualization of treatment and provide an opportunity for pre-emptive fibrosis control and better tumour treatment outcomes. The levels of activin A and follistatin were measured in fibroblasts derived from patients who developed severe radiation-induced fibrosis following radiotherapy and compared to fibroblasts from patients who did not. Both follistatin and activin A gene expression levels were increased following IR and the follistatin gene expression level was lower in the fibroblasts from fibrosis patients compared to controls at both basal levels and after IR. The major follistatin transcript variants were found to have a similar response to IR and both were reduced in fibrosis patients. Levels of follistatin and activin A secreted in the fibroblast culture medium also increased in response to IR and the relative follistatin protein levels were significantly lower in the samples derived from fibrosis patients. The decrease in the follistatin levels can lead to an increased bioactivity of activin A and hence may provide a useful measurement to identify patients at risk of a severe fibrotic response to IR. Additionally, follistatin, by its ability to neutralise the actions of activin A may be of value as an anti-fibrotic for radiation induced fibrosis.

3629 Background: Current chemotherapy regimens used during chemoradiation (CRT) are adequate for radiosensitization but suboptimal for systemic control. The aim of this study was to assess tolerability, and local/systemic benefits of new regimen delivering intensive chemotherapy and radical radiotherapy in an interdigitating manner. Methods: Phase II prospective study for patients (pts) with untreated simultaneous symptomatic primary and metastatic rectal cancer. The treatment regimen: 12 weeks long. FOLFOX chemotherapy (oxaliplatin 100mg/m2, leucovorin 200mg/m2, 5-FU 400mg/m2 bolus, all day 1, and 5FU continuous infusion [CI] 2.4 g/m2/46 hours) was given in weeks 1, 6, and 11. Pelvic CRT: 25.2 Gy in 3 weeks, 1.8 Gy/fr, with concurrent oxaliplatin 85mg/m2 day 1 and 5-FU CI 200mg/m2/day given in weeks 3-5, and 8-10. Pts received, in 12 weeks, 3 courses of FOLFOX and pelvic radiation 50.4 Gy with concurrent oxaliplatin/5-FU. All pt were staged with CT, MRI and FDG-PET before and post-treatment. Results: 26 pts treated. The mean age was 61 years, 69% male. Rectal primary MRI stage was T2 4%, T3 81% and T4 15%. Liver and lung metastases were present in 81%, and 35% of pts, respectively: 38% of patients had more than one site of metastatic disease. 24 pts (92%) completed the 12-week treatment regimen. All pts received the planned radiation dose. 65% of pts received the planned number of oxaliplatin courses with 88% of pts receiving at least 75% of the protocol oxaliplatin dose. In this 12-week period, grade 3 toxicities were neutropenia 23%, diarrhoea 15%, and radiation perineal skin reaction 12%. Only grade 4 toxicity was neutropenia: 15%. PET metabolic response (CR+PR) rate for rectal primary was 96%. Overall PET metabolic response rate for metastatic disease was 60% (CR rate 16%). Conclusions: It is thus feasible to deliver intensive chemotherapy and radical radiotherapy in an interdigitating manner to treat both primary and metastatic rectal cancer simultaneously. High completion and response rates are encouraging. This regimen is the subject of a current phase II neoadjuvant trial for resectable rectal cancer (TROG 09.01).

4105 Background: 18-fluorodeoxyglucose positron emission tomography (FDG-PET) improves the accuracy of staging and radiotherapy planning in anal cancer, and in other malignancies has prognostic val...

4559 Background: Accurate inguinal and pelvic nodal staging in anal cancer is important for prognosis and planning of (chemo)radiation fields. There is strong evidence for the impact of FDG-PET in staging and management of cancer, with early reports of an increasing role in outcome prognostication for a number of tumours. We aimed to determine the impact of FDG-PET on the nodal staging, radiotherapy planning and prognostication of patients with primary anal cancer. Methods: Sixty-two consecutive patients with anal cancer referred to a single tertiary oncology centre between August 1997 and November 2005 were staged with conventional imaging (CIm), computed tomography, magnetic resonance imaging and chest x-ray and by FDG-PET. The stage determined by CIm and the proposed management plan was prospectively recorded and changes in stage and management as a result of FDG-PET assessed. Patients were treated using uniform radiotherapy technique and dose. The accuracy of changes and prognostication of FDG-PET was validated by subsequent clinical follow-up. Kaplan-Meier survival analysis was used to assess survival for the cohort and by FDG-PET and CIm stage. Results: The TNM stage group was changed in 23% (14/62) as a result of FDG-PET (15% up-staged, 8% down-staged). Fourteen percent of T1 patients (3/22), 42% of T2 patients (10/24) and 38% of T3–4 patients (6/16), assessed using CIm, had a change in their N or M stage following FDG-PET. Sensitivity for nodal disease by FDG-PET and CIm was 92% and 72% respectively. The staging FDG-PET scan altered management intent in 3% (2/62), and altered radiotherapy fields in 13% (8/62). Estimated 5 year overall survival and progression free survival (PFS) for the cohort was 77.3% (95% CI 55.3%-90.4%) and 72.2% (95% CI 51.5%-86.4%) respectively. Estimated 5 year PFS for FDG-PET and CIm staged N2–3 disease was 70% (95% CI 42.8%-87.9%) and 55.3% (95% CI 23.3%-83.4%) respectively. Conclusions: FDG-PET shows increased sensitivity over CIm for staging nodal disease in anal cancer and changes treatment intent or radiotherapy fields in a significant proportion of patients. Improved 5 year PFS for FDG-PET staged N2–3 disease could be consistent with more accurate nodal staging and radiotherapy targeting. No significant financial relationships to disclose.

TPS4141 Background: Optimal management of patients with resectable gastric cancer remains unknown. Since the INT0116 and MAGIC trials, there are 2 standards of care for adjuvant therapy: postoperative chemoradiotherapy (CRT) and perioperative ECF chemotherapy. The important question arising from these studies is whether CRT is superior to chemotherapy alone as adjuvant therapy. This randomized phase II/III trial will compare CRT to chemotherapy alone in the preoperative setting. Methods: Patients with resectable adenocarcinoma of the stomach or gastroesophageal junction will be randomized to receive either preoperative chemotherapy alone (ECFx3 as per MAGIC regimen) or preoperative CRT (ECFx2 followed by 45Gy of radiation with concurrent 5-FU). Following surgery, both groups will receive 3 further cycles of ECF. The trial is being conducted in two Parts; Part I (phase II component) will recruit 120 patients with the aim of demonstrating sufficient efficacy and safety of preoperative CRT, as well as trial feasibility. Part II (phase III component) will recruit a further 632 patients to provide a total of 752. The primary endpoint for Part I is pathological complete response rate, and for Part 2 it is overall survival. The trial includes formal quality of life and biological sub-studies. In addition, the trial incorporates a rigorous quality assurance program that includes real time central review of radiotherapy plans and central review of surgical technique. Current status: This study is an international, intergroup trial led by the Australasian Gastro-Intestinal Trials Group (AGITG), in collaboration with the Trans-Tasman Radiation Oncology Group (TROG), European Organisation for Research and Treatment of Cancer (EORTC) and the NCIC Clinical Trials Group. To date, 36 patients have been recruited from 20 sites in Australia and New Zealand; European and Canadian sites will commence recruitment in 2012.

Background The optimal management of patients with resectable gastric cancer continues to evolve in Western countries. Following publication of the US Intergroup 0116 and UK Medical Research Council MAGIC trials, there are now two standards of care for adjuvant therapy in resectable gastric cancer, at least in the Western world: postoperative chemoradiotherapy and perioperative epirubicin/cisplatin/fluorouracil (ECF) chemotherapy. We hypothesize that adding chemoradiation to standard perioperative ECF chemotherapy will achieve further survival gains. We also believe there are advantages to administering chemoradiation in the preoperative rather than postoperative setting. In this article, we describe the TOPGEAR trial, which is a randomised phase III trial comparing control arm therapy of perioperative ECF chemotherapy with experimental arm therapy of preoperative chemoradiation plus perioperative ECF chemotherapy. Methods/Design Eligible patients with resectable adenocarcinoma of the stomach or gastroesophageal junction will be randomized to receive either perioperative chemotherapy alone (3 preoperative and 3 postoperative cycles of ECF) or perioperative chemotherapy plus preoperative chemoradiation. In the chemoradiation arm, patients receive 2 cycles of ECF plus chemoradiation prior to surgery, and then following surgery 3 further cycles of ECF are given. The trial is being conducted in two Parts; Part 1 (phase II component) has recruited 120 patients with the aim of assessing feasibility, safety and preliminary efficacy of preoperative chemoradiation. Part 2 (phase III component) will recruit a further 632 patients to provide a total sample size of 752 patients. The primary endpoint of the phase III trial is overall survival. The trial includes quality of life and biological substudies, as well as a health economic evaluation. In addition, the trial incorporates a rigorous quality assurance program that includes real time central review of radiotherapy plans and central review of surgical technique. Discussion TOPGEAR is an international, intergroup collaboration led by the Australasian Gastro-Intestinal Trials Group (AGITG), in collaboration with the Trans-Tasman Radiation Oncology Group (TROG), European Organisation for Research and Treatment of Cancer (EORTC) and the NCIC Clinical Trials Group. It addresses a globally significant question that will help inform future international standards for clinical practice in resectable gastric cancer. Trial registration Australian New Zealand Clinical Trials Registry: ACTRN12609000035224. Registered 30 May 2009