Therapeutic optimization in head and neck radiotherapy planning: Advocacy for 18FDG PET-CT in treatment condition.

INTRODUCTION: The necessity to perform 18FDG PET-CT both for initial tumour staging and for target volume delineation in head and neck cancers seems well established. The aim of the present study is to advocate the place and role of 18FDG PET-CT acquired in planning treatment position (18FDG PET-CT/RT). METHODS: Between March 2018 and July 2019, 22 patients with a squamous cell head and neck carcinoma treated by EBRT were included in the analysis. All these consecutive patients had a 18FDG PET-CT/RT. Three GTV volumes were defined. First, "GTV 40%" corresponded to 40% of SUVmax. "Visual GTV" was defined as the tumor volume obtained from the PET the nuclear medicine physician interpreted. The radiation oncologist used the medical record, clinical anatomy, CT simulation and 18FDG PET-CT/RT data ("GTV40%" and "visual GTV") to draw the GTV. RESULTS: Mean GTVs and mean "GTVs40%" were significantly different (P<0.001) with an intraclass index of 0.734. Mean "GTV40%" and mean "visual GTVs" were also significantly different (P<0.001) with an intraclass index of 0.72. Conversely, the difference between mean GTVs and mean "visual GTVs" were not significant (P=0.11) with an intraclass index of 0.91. Mean DICE between "GTVs40%" and GTV was 0.7 (ranging from 0.2 to 0.9). The mean intersection between GTVs and "visual GTVs" volumes was 0.8 (ranging from 0.4 to 1). The difference between DICES was significant (P=0.015), "visual GTV"/GTV DICE was the smallest. CONCLUSION: 18FDG PET-CT/RT definitely remains the imaging modality that individualized/customized head and neck cancer treatment needs.

Focus on the expected quality of reporting in SBRT/radiosurgery prospective studies: how far have we come in 30 years?

OBJECTIVES: We aimed at describing and assessing the quality of reporting in all published prospective trials about radiosurgery (SRS) and stereotactic body radiotherapy (SBRT). METHODS: The Medline database was searched for. The reporting of study design, patients' and radiotherapy characteristics, previous and concurrent cancer treatments, acute and late toxicities and assessment of quality of life were collected. RESULTS: 114 articles - published between 1989 and 2019 - were analysed. 21 trials were randomised (18.4%). Randomisation information was unavailable in 59.6% of the publications. Data about randomisation, ITT analysis and whether the study was multicentre or not, had been significantly less reported during the 2010-2019 publication period than before (respectively 29.4% vs 57.4% (p < 0.001), 20.6% vs 57.4% (p < 0.001), 48.5% vs 68.1% (p < 0.001). 89.5% of the articles reported the number of included patients. Information about radiation total dose was available in 86% of cases and dose per fraction in 78.1%. Regarding the method of dose prescription, the prescription isodose was the most reported information (58.8%). The reporting of radiotherapy characteristics did not improve during the 2010 s-2019s. Acute and late high-grade toxicity was reported in 37.7 and 30.7%, respectively. Their reporting decreased in recent period, especially for all-grade late toxicities (p = 0.044). CONCLUSION: It seems necessary to meet stricter specifications to improve the quality of reporting. ADVANCES IN KNOWLEDGE: Our work results in one of the rare analyses of radiosurgery and SBRT publications. Literature must include necessary information to first, ensure treatments can be compared and reproduced and secondly, to permit to decide on new standards of care.

Positron emission tomography for radiotherapy planning in head and neck cancer: What impact?

PET-computed tomography (CT) plays a growing role to guide target volume delineation for head and neck cancer in radiation oncology. Pretherapeutic [18F]FDG PET-CT adds information to morphological imaging. First, as a whole-body imaging modality, it reveals regional or distant metastases that induce major therapeutic changes in more than 10% of the cases. Moreover, it allows better pathological lymph node selection which improves overall regional control and overall survival. Second, locally, it allows us to define the metabolic tumoral volume, which is a reliable prognostic feature for survival outcome. [18F]FDG PET-CT-based gross tumor volume (GTV) is on average significantly smaller than GTV based on CT. Nevertheless, the overlap is incomplete and more evaluation of composite GTV based on PET and GTV based on CT are needed. However, in clinical practice, the study showed that using GTV PET alone for treatment planning was similar to using GTVCT for local control and dose distribution was better as a dose to organs at risk significantly decreased. In addition to FDG, pretherapeutic PET could give access to different biological tumoral volumes - thanks to different tracers - guiding heterogeneous dose delivery (dose painting concept) to resistant subvolumes. During radiotherapy treatment, follow-up [18F]FDG PET-CT revealed an earlier and more important diminution of GTV than other imaging modality. It may be a valuable support for adaptative radiotherapy as a new treatment plan with a significant impact on dose distribution became possible. Finally, additional studies are required to prospectively validate long-term outcomes and lower toxicity resulting from the use of PET-CT in treatment planning.

Chemoradiation phase II trials: re-exploring a world of missed opportunities.

Background: Phase II trials are designed to assess the efficacy/toxicity ratio of experimental treatments and select those worth being tested in phase III trials. Although crucial limitations were identified when concurrent chemoradiation (cCRT) phase III trials characteristics were assessed, features of cCRT phase II trials have never been reported. The objective was to describe features of all cCRT phase II trials. Methods and material: Requests were performed in the Medline database (via PubMed). The latest update was performed in April 2016, using the following MESH terms: 'clinical trials: phase II as topic', 'chemoradiotherapy'. Results: Four hundred and fifty-eight cCRT phase II trials were identified. They were mainly multicenter (51.5%), single arm studies (77.7%) published after 2011 (55.0%). The median number of included patients was 52. Primary endpoints were mainly response rate (20.5%), pathological complete response (14.4%) and overall survival (12.6%). The primary endpoint was not defined in 22% of studies. Tumors were mostly lung (23.1%), head and neck (20.3%), colorectal (16.6%) and esophagogastric cancer (14.6%) treated at a locally advanced setting (81.7%). 55.2% of trials used 3D-conformal radiotherapy and 9.1% intensity-modulated radiotherapy, mainly with normo-fractionation (82.0% of the 573 arms with radiotherapy). Radiation technique was not reported in 19.9% of studies. Associated anticancer drugs (563 arms) were mainly conventional chemotherapies (559 arms): cisplatin (46.2%) and 5-fluorouracil (28.3%). Non cytotoxic agents (targeted therapies, immunotherapies) were tested in 97 arms (17%). With a median follow-up of 31 months, acute grades 3-5 were reported in 98.5% of studies and late toxicities in 44.5%. Follow-up was not reported in 17% of studies. Conclusions: cCRT phase II trials featured severe limitations, with outdated radiation techniques, insufficient reporting of crucial data and a small number of included patients. This certainly limited the impact of conclusions and hindered the development of successful phase III trials.