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Background: There is no clear consensus on the use of re-irradiation (reRT) in the management of locally recurrent rectal cancer (LRRC). The aim of the present study was to investigate all reRT adm...

Biologic image guided radiotherapy (RT) with escalated doses to tumour sub volumes challenges today's RT dose planning and delivery systems. In this phantom study, we verify the capability of a clinical dose planning and delivery system to deliver an 18F-FDG-PET based dose painted treatment plan to a lung tumour. Furthermore, we estimate the uncertainties of the dose painted treatment compared to conventional RT plans. An anthropomorphic thorax phantom of polystyrene and polyurethane was constructed based on CT images of a lung cancer patient. 101 EPR/alanine dosimeters were placed in separate cavities within the phantom. IMRT and VMAT plans were generated in Eclipse (version 10.0, Analytical Anisotropic Algorithm version 10.2.28, Varian Medical Systems, Inc.) for 6 and 15 MV photons, based on 18F-FDG-PET/CT images of the patient. A boost dose of 3.8 Gy/fraction was given to the 18F-FDG-avid region (biological planning volume; BTV), whereas 3.1 Gy/fraction was planned to the planning target volume (PTV, excluding the BTV). For the homogenous plans, 3.2 Gy/fraction was given to the PTV. Irradiation of the phantom was carried out at a Varian Trilogy linear accelerator (Varian Medical Systems, Inc.). Uncertainties involved in treatment planning and delivery were estimated from portal dosimetry gamma evaluation. Measured and calculated doses were compared by Bland-Altmann analysis. For all treatment plans, all dose-volume objectives could be achieved in the treatment planning system. The mean absolute differences between calculated and measured doses were small (

Background: Early confirmation of the effect of brachytherapy for choroidal melanoma showing that tumour coverage is valuable. The irradiated retinal pigment epithelium (RPE) commonly develops atrophy. This study compares the fundus autofluorescence (AF) changes to the development of RPE atrophy following brachytherapy. Methods: Retrospective study of 19 patients treated with 106Ru and 2 with 125I plaques with either a 3- or 6-month follow-up period. Ultra-widefield (UW) composite colour and AF images were obtained with Optomap 200Tx and interpreted as complete, partial, or no RPE changes and complete or partial hyperautofluorescence, hypoautofluorescence, or isoautofluorescence. Results: At the 3-month follow-up, 9 of 13 patients (69%) (95% confidence interval [CI], 0.389–0.896) treated with 106Ru plaques developed complete homogenous hyperautofluorescence surrounding the tumour, but only 1 of 13 (8%) (95% CI, 0.004–0.379) developed complete RPE atrophy at the same time point. Six patients in the 106Ru plaque group had their first follow-up with UW imaging at 6 months. Four of them developed homogenous hyperautofluorescence and none developed complete RPE atrophy around the tumour. The 2 patients treated with 125I did not demonstrate any clear RPE or AF changes. Conclusion: The effect of 106Ru plaque treatment on fundus UW imaging is detected as homogenous and well-demarcated hyperautofluorescence before visible RPE atrophy.

BACKGROUND: Many patients with rectal cancer receive radiotherapy as a component of primary multimodality treatment. Although local recurrence is infrequent, reirradiation may be needed to improve resectability and outcomes. This systematic review investigated the effects of reirradiation in terms of feasibility, toxicity, and long-term outcomes.METHODS: A Medline, Embase and Cochrane search resulted in 353 titles/abstracts. Ten publications describing seven prospective or retrospective studies were included, presenting results of 375 patients reirradiated for rectal cancer.RESULTS: Median initial radiation dose was 50.4Gy, median 8-30months before reirradiation. Reirradiation was mostly administered using hyperfractionated (1.2-1.5Gy twice-daily) or 1.8Gy once-daily chemoradiotherapy. Median total dose was 30-40Gy to the gross tumour volume with 2-4cm margins. Median survival was 39-60months in resected patients and 12-16months in palliative patients. Good symptomatic relief was reported in 82-100%. Acute toxicity with diarrhoea was reported in 9-20%, late toxicity was insufficiently reported.CONCLUSIONS: Reirradiation of rectal cancer to limited volumes is feasible. When curative resection is possible, the goal is radical resection and long-term survival, and hyperfractionated chemoradiotherapy should be preferred to limit late toxicity. Reirradiation yielded good symptomatic relief in palliative treatment.

OBJECTIVE: To assess the role of [(18)F]fluorodeoxyglucose (FDG) positron emission tomography (PET), obtained before and during chemoradiotherapy, in predicting locoregional failure relative to clinicopathological factors for patients with anal cancer. METHODS: 93 patients with anal squamous cell carcinoma treated with chemoradiotherapy were included in a prospective observational study (NCT01937780). FDG-PET/CT was performed for all patients before treatment, and for a subgroup (n = 39) also 2 weeks into treatment. FDG-PET was evaluated with standardized uptake values (SUV(max/peak/mean)), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and a proposed Z-normalized combination of MTV and SUV(peak) (ZMP). The objective was to predict locoregional failure using FDG-PET, tumor and lymph node stage, gross tumor volume (GTV) and human papilloma virus (HPV) status in univariate and bivariate Cox regression analysis. RESULTS: N3 lymph node stage, HPV negative tumor, GTV, MTV, TLG and ZMP were in univariate analysis significant predictors of locoregional failure (p < 0.01), while SUV(max/peak/mean) were not (p > 0.2). In bivariate analysis HPV status was the most independent predictor in combinations with N3 stage, ZMP, TLG, and MTV (p < 0.02). The FDG-PET parameters at 2 weeks into radiotherapy decreased by 30–40 % of the initial values, but neither absolute nor relative decrease improved the prediction models. CONCLUSION: Pre-treatment PET parameters are predictive of chemoradiotherapy outcome in anal cancer, although HPV negativity and N3 stage are the strongest single predictors. Predictions can be improved by combining HPV with PET parameters such as MTV, TLG or ZMP. PET 2 weeks into treatment does not provide added predictive value. ADVANCES IN KNOWLEDGE: Pre-treatment PET parameters of anal cancer showed a predictive role independent of clinicopathological factors. Although the PET parameters show substantial reduction from pre- to mid-treatment, the changes were not predictive of chemoradiotherapy outcome.

Dose painting by numbers (DPBN) is a method to deliver an inhomogeneous tumor dose voxel-by-voxel with a prescription based on biological medical images. However, planning of DPBN is not supported by commercial treatment planning systems (TPS) today. Here, a straightforward method for DPBN with a standard TPS is presented.DPBN tumor dose prescription maps were generated from (18)F-FDG-PET images applying a linear relationship between image voxel value and dose. An inverted DPBN prescription map was created and imported into a standard TPS where it was defined as a mock pre-treated dose. Using inverse optimization for the summed dose, a planned DPBN dose distribution was created. The procedure was tested in standard TPS for three different tumor cases; cervix, lung and head and neck. The treatment plans were compared to the prescribed DPBN dose distribution by three-dimensional (3D) gamma analysis and quality factors (QFs). Delivery of the DPBN plans was assessed with portal dosimetry (PD).Maximum tumor doses of 149%, 140% and 151% relative to the minimum tumor dose were prescribed for the cervix, lung and head and neck case, respectively. DPBN distributions were well achieved within the tumor whilst normal tissue doses were within constraints. Generally, high gamma pass rates (89% at 2%/2 mm) and low QFs (2.6%) were found. PD showed that all DPBN plans could be successfully delivered.The presented methodology enables the use of currently available TPSs for DPBN planning and delivery and may therefore pave the way for clinical implementation.