Symptom documentation and tumor repopulation factors as a basis for treatment modifications in non-small cell lung cancer radiotherapy

• Κύριος συγγραφέας: Χαλίμου, Ιωάννα
• Άλλοι συγγραφείς: Σακελλαρόπουλος, Γεώργιος
• Μορφή: Thesis
• Γλώσσα: English
• Έκδοση: 2010
• Θέματα: Radiotherapy; Non-small cell lung cancer; Advanced; Ακτινοθεραπεία; Καρκίνος πνεύμονα; 616.994 240 6

Recent studies have suggested significant variation in radiotherapy schedules used to treat advanced NSCLC, both between different centres as well as between countries. In this study, treatment methodologies have been explored using management plans proposed by radiation oncologists when given general questions and theoretical case histories for patients with advanced NSCLC. Methods and Materials The survey was conducted by sending a questionnaire to twenty four radiotherapy centres in Europe. The questionnaire was composed of two sections. The first section concerned reasons for starting radiotherapy, parameters that influence the choice of total dose and fractionation for radiotherapy and the kind of equipment that is used. The second section examines five case histories and asked the responders about the management of these five theoretical patients also regarding the radiotherapy techniques proposed and the aim of treatment (radical or palliative). Furthermore, trials comparing different regimens of palliative radiotherapy in patients with NSCLC were compared. Nineteen trials were reviewed. There were important differences in the doses of radiotherapy investigated, the patient characteristics and the outcome measures. Results In the first part responders (70% of the centres) suggested as the most important factors that influence the choice of total dose and fractionation for radiotherapy, distant metastases, performance status of the patient, lung function and size of the primary tumour. The most common reasons for starting the treatment is not only symptom relief, but also cure and prolongation of life. In the second part, more than 95% of the responders replied that they would give radiotherapy in each of these cases. The median total doses proposed where 20Gy/5fractions/1week or 30Gy/10fractions/2weeks for cases A and D (equivalent dose for fractionation 2Gy per fraction=23 and 33Gy) and 60-68Gy/30fractions/6weeks or 68Gy/34fractions/7weeks for cases B, C and E. For case E, 20% of the responders suggested Stereotactic Body Radiotherapy with 63Gy in 3 Fractions. The total dose and number of fractions of radiotherapy could be related to the perceived aims and expectations of treatment e.g. those aiming to extent life would give significantly higher total doses in a larger number of fractions, whereas those aiming to relieve symptoms would give significantly lower total doses. For the review to the literature there is no strong evidence that any regimen gives greater palliation. Higher dose regimens give more acute toxicity, especially oesophagitis. There is evidence for a modest increase in survival (5% at 1 year and 3% at 2 years) in patients with better performance status (PS) given higher dose radiotherapy. Some regimens are associated with an increased risk of radiation myelitis. Conclusions This survey demonstrates a range of treatment strategies for advanced and inoperable NSCLC within Europe. There are a number of factors that influence the perceived aims of treatment and treatment planning. These factors should be taken into account when evaluating the effectiveness of different irradiation techniques, especially in the determination of radiobiological parameters and dose-response relations. The majority of patients should be treated with short courses of palliative radiotherapy, of 1 or 2 fractions. Care should be taken with the dose to the spinal cord. The use of high dose palliative regimens should be considered for and discussed with selected patients with good performance status. More research is needed into reducing the acute toxicity of large fraction regimens and into the role of radical compared to high dose palliative radiotherapy. In the future, large trials comparing different RT regimens may be difficult to set up because of the increasing use of systemic chemotherapy. Trials looking at how best to integrate these two modalities, particularly in good PS patients need to be carried out.