Évaluation des effets secondaires des radiations ionisantes

Potential screening assays for individual radiation sensitivity and susceptibility and their current validation state

Purpose: The workshop on 'Individual Radiosensitivity and Radiosusceptibility' organized by MELODI and CONCERT on Malta in 2018, evaluated the current state of assays to identify sensitive and susceptible subgroups. The authors provide an overview on potential screening assays detecting individuals showing moderate to severe early and late radiation reactions or are at increased risk to develop cancer upon radiation exposure.Conclusion: It is necessary to separate clearly between tissue reactions and stochastic effects such as cancer when comparing the existing literature to validate various test systems. Requirements for the assays are set up. The literature is reviewed for assays that are reliable and robust. Sensitivity and specificity of the assays are regarded and scrutinized for modifying factors. Accuracy of an assay system is required to be more than 90% to balance risks of adverse reactions against risk to fail to cure the cancer. No assay/biomarker is in routine use. Assays that have shown predictive potential for radiosensitivity include SNPs, the RILA assay, and the pATM assay. A tree of risk guideline for radiologists is provided to assist medical treatment decisions. Recommendations for effective research include the setup of common retrospective and prospective cohorts/biobanks to validate current and future tests.

The INTER-ROMA Project - a Survey among Italian Radiation Oncologists on Their Approach to the Treatment of Bone Metastases

Aims and background

Radiotherapy has an established palliative role for bone metastases but despite the large number of patients treated there is still controversy surrounding the optimal radiotherapy schedule to prescribe. The aim of this survey was to determine the decision patterns of Italian radiation oncologists in four different clinical cases of patients with bone metastases.

Methods and study design

During the latest national meeting of the Italian Association of Radiation Oncology (AIRO), four clinical cases were presented to attending radiation oncologists. The cases were different with respect to the histology of the primary tumor, performance status, pain before and after analgesics, tumor site, and radiological characteristics of the metastatic lesions. For each clinical case the respondents were asked to give an indication for treatment; prescribe doses, volumes and treatment field arrangements; decide whether to prescribe prophylactic supportive therapy or not; and provide information about factors that particularly influenced prescription. Finally, a descriptive statistical analysis was performed.

Results

Three hundred questionnaires were distributed to radiation oncologists attending the congress. One hundred twenty-five questionnaires were returned but only 122 (40.6%) were adequately completed and considered for the analysis. Considerable differences were observed among radiation oncologists in prescribing and delivering radiotherapy for bone metastases. There was also a notable divergence from international guidelines, which will be discussed in this report.

Conclusions

Despite the results of clinical trials, Italian radiation oncologists differ considerably in their decisions on treatment doses and volumes. National guidelines are needed in order that patients can be treated uniformly and better data will become available for evidence-based palliative radiotherapy.

[Single French centre retrospective analysis of local control after high dose radiotherapy with or without chemotherapy and local control for Pancoast tumours]

PURPOSE

Superior sulcus non-small cell lung cancer represents less than 5% of all lung cancers and is a challenge for the physicians because of clinical presentation, treatments related toxicities and poor prognosis. The aim of this preliminary retrospective report is to present outcomes of patients affected by a superior sulcus non-small cell lung cancer, treated by high dose radiotherapy (>60 Gy) with or with our chemotherapy.

PATIENTS AND METHODS

All adult inoperable or unresectable patients (≥18 years) with a clinical and radiological diagnosis of superior sulcus non-small cell lung cancer treated in our department by radiotherapy with or without chemotherapy were retrospectively analysed. Primary endpoint was the local control. Overall survival, metastasis free survival and toxicity rates were also analysed and reported.

RESULTS

From January 1999 to June 2009, 12 patients were treated by exclusive high-dose radiochemotherapy. Median age was 53 years (range: 33-64 years); mean follow-up time was 20 months (range: 2-75 months). Mean local control, overall survival and metastasis free survival were 20.2, 22 and 20 months, respectively. At the time of this analysis, seven patients died of cancer and three of them presented only a metastatic disease progression. One patient died of acute cardiac failure 36 months after the end of radiochemotherapy and was disease free. Treatment was well tolerated and any acute and/or late G3-4 toxicity was recorded (NCI-CTC v 3.0 score).

CONCLUSION

This analysis confirms the interest of exclusive high-dose radiochemotherapy in treating inoperable superior sulcus non-small cell lung cancer patients, in achieving good local control and overall survival rates.

[Dosimetry comparison of irradiation with conformal radiotherapy, intensity modulated radiotherapy, conformal radiotherapy in stereotactic conditions and robotic stereotactic radiotherapy for benign brain tumours]

PURPOSE

To compare several techniques in order to determine the best treatment for benign brain tumours.

METHODS AND PATIENTS

A retrospective study was performed for five patients who received 3D-conformal radiotherapy, intensity modulated radiotherapy or CyberKnife(®). These patients had a meningioma, a pituitary tumour, a craniopharyngioma or a neurinoma. In each case, these treatment plans were optimised and compared with the three other dosimetries. Radiobiological or positioning parameters were evaluated, as well as dosimetric parameters, in order to compare treatments with different characteristics.

RESULTS

The dosimetric parameters showed that the choice of treatment seemed to be determined mostly by tumour size, shape and proximity with organs at risk (not tumour localisation). Whereas the results showed no significant deviations with regards to the radiobiological parameters. Therefore, with these parameters, it was difficult to give priority to a treatment.

CONCLUSIONS

With regards to benign brain tumours of medium or large size, intensity modulated radiotherapy seemed the recommended treatment. It enabled to obtain a good ratio between efficacy and toxicity for tumours that are really close to organs at risk. Concerning small benign brain tumours, the CyberKnife(®) was probably the best treatment.

[Interest of blood markers in predicting radiation-induced toxicity]

The oncologic outcome and the total dose are highly correlated with the treatment by ionizing radiation. The dose increase (total or per fraction) may provoke late-side effects that are potentially irreversible. The radiation-induced CD8 lymphocyte apoptotic value and the molecular modifications within the lymphocyte are capable of predicting the level of risk of developing late-side effects after curative intent radiotherapy. In this review, we present the different blood assays in this setting and discuss the current possibilities of researches, namely those involving the proteomic process.