B. Reymen

PO-0929: Dual Energy CT imaging of tumour vasculature in NSCLC: an intra-patient comparison with DCE-CT

Purpose or Objective: Quantification of vasculature is frequently performed by dynamic contrast enhanced CT (DCE-CT) or MRI imaging. However, there are some limitations to this technique: DCE-CT requires a detailed kinetic fitting procedure, a prolonged acquisition time with increased dose to the patient, has a limited FOV and is not easy to implement in clinical routine. Dual Energy CT is an evolving field in CT image analysis that allows quantification of contrast material uptake using a single acquisition, making it easily implementable in a clinical workflow. Therefore we investigated the correlation between the DCE-CT derived vasculature parameters, blood flow and blood volume, with iodine related attenuation measured on a Dual Energy CT acquisition for non-small cell lung cancer patients.

OC-0129: Nitroglycerin decreases the hypoxic fraction of non-small cell lung cancer lesions

ESTRO 35 2016 _____________________________________________________________________________________________________ It is well known that MR data contains detailed information with high tissue contrast and that PET imaging gives molecular/biochemical information with high molecular sensitivity but what is the added value? A major goal with treatment planning is to delineate the tumor volume, which can be done with both MR and PET, but since the both modalities show different characteristics of the tumor the volume might differ between them. Challenges from the imaging point of view will be discussed. The availability to PET/CT is much higher and the challenges with this method are fewer. Some comparison of the two hybrid modalities will be done. The majority of PET studies are done with the tracer fluorodexyglucose, FDG, but beyond FDG a large number of tracer are available, all giving information about different biochemical properties of the tumor. A few of these tracers will be presented and discussed.

OC-0205: Prognostic value of pre-RT PET metrics of lymph nodes vs. primary tumor in NSCLC: which holds more information?

Purpose/Objective: Loco-regional recurrences remain frequent in locally advanced non-small cell lung cancer (NSCLC) patients and are predominantly located in the area of the primary tumor. Improved tumor control might be accomplished by dose-escalation and dose-redistribution. The PET-boost trial (NCT01024829) is an ongoing randomized phase II trial investigating individualized accelerated doseescalation to the entire primary tumor (arm A) or redistributed to regions of high FGD-uptake within the primary tumor (arm B). We present a planned interim analysis of the toxicity of 63 randomized patients. Materials and Methods: Patients with NSCLC stage IB-III, a primary tumor (PT) ≥4 cm and a SUVmax ≥5 are treated with chemo-radiation or radiotherapy alone. Treatment plans are designed using a pre-treatment FDG-PET-CT-scan with similar dose limits to OAR as in conventionally treated patients. If normal tissue constraints allow dose-escalation using an integrated boost ≥72 Gy in 24 fractions to the PT and with equal mean lung dose for both study arms, a patient is randomized to arm A or arm B. Involved lymph nodes are treated to a fractionation dose of 66 Gy in 24 fractions. Toxicity is scored according to the CTCAEv3.0 criteria. Endpoints are local progression-free survival at 1 year, toxicity, overall survival and quality of life. Results: From April 2010 to March 2014, 32 patients were randomized to arm A and 31 patients to arm B. Forty-eight patients received concurrent chemo-radiotherapy. Median follow-up was 25.5 months. The mean PT volume in arm A was 123.4cc and in arm B 181.5cc. Mean prescribed dose to the planning target volume of the primary tumor was 3.3 Gy (range 3.0-4.0 Gy) in arm A and 3.9 Gy (range 3.2-5.4 Gy) in arm B. Grade ≥3 dysphagia and dyspnea during treatment occurred in 7 and 2 patients (11 and 3%). Grade ≥3 esophagitis and pneumonitis after treatment was seen in 11 and 6 patients (17.5% and 9.5%). Hematologic toxicity grade ≥3 was observed in 5%. Four out of 63 patients (6.3%) died due to pulmonary hemorrhage. Conclusions: This interim toxicity analysis of the randomized phase II PET-boost trial shows that dose-escalation is feasible in 63 randomized patients. The toxicity observed during and after treatment shows no excess or unexpected toxicity.

PD-0097: Impact of new Dutch guideline on patient selection for WBRT in a large lung cancer cohort

local control (LC), regional control (RC) and metastasis-free survival (MFS). A strong correlation between total lymph node tumour volume and Nstage was found (Rs=0.93, P<0.01). MFS was worse with involvement of the lower neck levels (Rs=0.345, P<0.01). Patients with larger total lymph node tumour volumes had poorer RC and MFS rates, independent of treatment regimen. For total lymph node volumes up to 3.5 cm, MFS can be improved by ARCON (P<0.01). Conclusions: The strong prognostic value of T-stage and primary tumour volume, observed in retrospective analyses was not confirmed in patients treated in a prospective randomised trial with accelerated radiotherapy with or without carbogen breathing and nicotinamide. Results of this study indicate that (biological) factors other than primary tumour volume and T-stage are needed to select patients with laryngeal cancer for treatment intensification.