Important new results from EORTC to be presented at ESTRO 2023

Brussels, April 14, 2023 – Radiation oncology is among the main pillars of the EORTC scientific strategy and plays a vital part in its mission to improve clinical research through multidisciplinary partnerships. The annual ESTRO congress provides an opportunity for radiation oncologists to present results from EORTC studies that advance radiotherapy (RT) treatment and provide benefits for patients, and this year’s congress, to be held in Vienna from 12-16 May, is no exception.

Professor Filippo Alongi will present new results from the first patients included in the ESTRO/EORTC E2-RADIatE OligoCare cohort. Oligometastatic disease (OMD) is an intermediate state where a primary cancer has metastasised to a limited number of regions. It is not a homogenous cancer state, and this makes the determination of optimal treatment strategies difficult. The analysis to be presented is based on 1468 patients from the first 1600 enrolled. “Traditionally, treatment for metastases has been considered to be palliative rather than curative, but the concept of oligometastasis has increased interest in different forms of treatment,” says Prof Alongi.

The patients in the cohort were treated with the high precision therapy stereotactic body radiation (SBRT) at 32 centres in nine European countries for oligometastatic breast, colorectal, non-small cell lung, or prostate cancer. In most patients, fewer than four metastases were irradiated, with most patients receiving treatment for a single metastasis. Very little high grade toxicity was found, and the vast majority of patients were still alive six months after treatment. “Although we believe that RT is useful in cases of oligometastasis, there are still few data from randomised trials to confirm this. The Oligocare project is helping us to consolidate evidence and build up a large database to evaluate the impact of the use of SBRT in these patients,” Prof Alongi says.

For more information: Session

Note: Further patients have been included in the analysis to be presented, hence the difference from the abstract as submitted.

New results from the EORTC 22922/10925 breast cancer study will also be presented. The study, carried out between 1996 and 2004, randomised 4004 stage 1 – 3 breast cancer patients to receiving lymph node radiation after surgery, or not receiving it. Primary surgery included mastectomy or breast conservation surgery (BCS), and was followed by whole breast/chest wall/RT in almost every case. The results to be presented arise from the analysis of the effect on local (LR) and regional recurrence (RR) of internal mammary and medial supraclavicular lymph node (IM-MS) irradiation.

Breast cancer can spread to the regional lymph nodes located under the arm, near the collarbone, and under the breastbone, but there are uncertainties surrounding the use of lymph node radiation and more specifically about for which groups of patients it can be of most value. “Even though the trial was conducted almost 20 years ago,” says presenter Dr Orit Kaidar-Person, “the meticulous work done by EORTC researchers and the team at headquarters allowed us to perform an additional, unplanned analysis that can benefit breast cancer patients and help decision-making in RT.”

The researchers mapped the special location of locoregional recurrences following the different therapies. The most important findings, they say, are the low rate of locoregional recurrences, and that the extent of locoregional therapy impacts significantly on LR and RR rates and spatial location. “We will be carrying out further research to try to understand these results in the context of disease stages and RT techniques. In the meantime, these data are unique and may influence future decision-making for these patients,” says Dr Kaidar-Person.

For more information: Session

Professor Ursula Nestle will present results from the EORTC 22113-08113 Lungtech trial at the conference. The trial looked at the safety and efficacy of the use of the high precision treatment stereotactic body radiotherapy (SBRT) in patients with inoperable central lung tumours. Although SBRT has had promising results in patients with peripheral tumours, the position of central tumours close to other organs can lead to severe toxicities. Indeed, the trial closed early, in 2017, because repeated safety-related halts in treatment made it difficult to enrol sufficient patients to have a dependable result.

Eligible patients with non-small cell lung cancer from 13 sites in six European countries were recruited to the trial between 2015 and 2017. “We found a high rate of local tumour control, with a median overall survival (OS) rate of 46 months, and a three-year OS of 61%,” says Prof Nestle. However, these patients also had other illnesses (comorbidities), particularly affecting the heart and lungs.

“Although the small numbers included in the analysis make it difficult to be certain, we observed a relevant but not excessive risk of severe late toxicity after SBRT of central tumours”, Professor Nestle says. “But almost all of the patients treated were very comorbid. As SBRT is highly efficient in terms of tumour control, the risks must be put in context with the comorbidities and weighed against those of tumour progression with limited therapeutic options on a case by case basis. We are happy that our prospective data will help informed decision-making in the future.”

For more information: Session

The aim of radiotherapy is to achieve a high level of local tumour control with a low risk of normal tissue complication probability, or NTCP. It is therefore crucial to identify models that can predict which patients are least likely to suffer side effects from new, advanced RT techniques such as proton therapy. There are several NCTP models for each side effect, and new research to be presented at the conference will help identify their quality and applicability.

Dr Makbule Tambas and colleagues originally identified over 10 000 potentially relevant articles and 55 ongoing trials. Further screening reduced numbers to 755, and then to 114. “We were then able to summarise the current evidence on their predictive performance. This review will be helpful in understanding which models are useful for therapeutic decision-making, and to what extent they should be able, as well as which models should not be used and which are promising but still require further investigation,” she says. “Our results show that there is a need for external validation models in clinical practice, and an improvement in the quality of the conduct and reporting of prediction model studies in this subject.”

For more information: Session

Dr Daniel Portik will present new results from the ongoing EORTC 1420 ‘Best of’ trial, which aims to compare swallowing function after trans-oral surgery versus radiotherapy in head and neck cancer. Problems with swallowing (dysphagia) are common in head and neck cancer patients after curative treatment, and have a major impact on patients’ quality of life. The inclusion of quality assurance in radiotherapy trials is essential in order to ensure patient safety and to improve treatment outcomes.

Participating centres were required to complete a benchmark case procedure by delineating and planning a specific patient case according to the study protocol. The study then analysed differences in contouring (the outlining of the area to be irradiated) and treatment planning when compared to a gold standard case. Despite the drawing up of detailed contouring protocols, tumour delineation remained the main reason for the plans having to be resubmitted for approval, and this happened in 32 out of the 42 participating centres.

“This outcome was particularly important, since the trial asked participating centres to delineate new swallowing structures intended to decrease radiation-induced side effects,” says Dr Portik. “Our results underline the importance of rigorous RTQA measures in order to maintain high standards, and will help assure patients that they are receiving the best possible care.”

For more information: Session

Dr Denis Lacombe, EORTC CEO, said: “As cancer care moves further towards individually-tailored treatments, multidisciplinarity becomes more and more important. Radiotherapy plays a major part in providing high quality patient care and EORTC is committed to moving forward in RT research, which we see as an essential tool in our mission to provide the best treatment for every cancer patient.”