Intensity Of Radiotherapy Research Articles

The Evolving Role of Radiotherapy for Pediatric Cancers With Advancements in Molecular Tumor Characterization and Targeted Therapies.

Ongoing rapid advances in molecular diagnostics, precision imaging, and development of targeted therapies have resulted in a constantly evolving landscape for treatment of pediatric cancers. Radiotherapy remains a critical element of the therapeutic toolbox, and its role in the era of precision medicine continues to adapt and undergo re-evaluation. Here, we review emerging strategies for combining radiotherapy with novel targeted systemic therapies (for example, for pediatric gliomas or soft tissue sarcomas), modifying use or intensity of radiotherapy when appropriate via molecular diagnostics that allow better characterization and individualization of each patient’s treatments (for example, de-intensification of radiotherapy in WNT subgroup medulloblastoma), as well as exploring more effective targeted systemic therapies that may allow omission or delay of radiotherapy. Many of these strategies are still under investigation but highlight the importance of continued pre-clinical and clinical studies evaluating the role of radiotherapy in this era of precision oncology.

Radiobiological models in prediction of radiation cardiotoxicity.

Coronary disease induced by previous radiotherapy is the most common cause of death among patients treated with radiotherapy for cancer. Risk factors that may affect the frequency and intensity of radiotherapy's cardiac toxicity are primarily the radiation dose and the volume of the heart exposed to radiation. The prolonged survival time of patients after radiotherapy, but also the intensive development of modern radiotherapy techniques results in the necessity of precise estimation of both tumor control probability, and the risk of normal tissue damage, thus the models describing the probability of complications in normal tissues have also been developed. The response from the cardiovascular system to high-dose radiation is known and associated with a pro-inflammatory response. However, the effect of low doses may be completely different because it induces an anti-inflammatory response. Also, there is no unambiguous answer to the question of whether RICD is a deterministic effect. Moreover, there is a lack of literature data on the use of known radiobiological models to assess the risk of cardiovascular complications. The models described are general and concerns any healthy tissue. Therefore, when planning treatment for patients, particular attention should be paid to the dose and area of ​​the heart to be irradiated.

Time Factor in Radiotherapy and Chemotherapy for Limited Disease Small-Cell Lung Cancer

The prognostic significance of planned and unplanned gaps in radiotherapy and chemotherapy for limited-disease small-cell lung cancer (LD-SCLC) has been retrospectively evaluated in a series of 245 patients. All of them had cisplatine-based chemotherapy and fractionated radiotherapy. There was substantial heterogeneity in overall radiation treatment time and dose-intensity of chemotherapy attributable mostly to planned and unplanned gaps in therapy. Several variables that potentially may influence survival of the patients after treatment, including duration of treatment gaps, and dose-intensity of chemotherapy and radiotherapy were analyzed using univariate and multivariate Cox regression model. The following variables had significant and independent negative influence on survival in a multivariate model: performance status ZUBROD > 0 (p < 0.0001), metastases to supraclavicular nodes (p = 0.001), dyspnoea according to Borg scale > 2 (p = 0.004) and the average dose intensity of radiotherapy < 80 percent (p = 0.02). An independent association between total dose and survival also has been found. The dose-intensity of chemotherapy did not appear to significantly influence survival. While due to the retrospective character of the present research, this conclusion must be regarded as hypothesis-generating only, we assume that within the range of doses and dose-intensitites used in the present group the preventable gaps in radiotherapy and undue reduction of total radiation dose should be promptly avoided, while gaps in chemotherapy can be deemed acceptable if crucially demanded by the tolerance of treatment.

Recombinant human erythropoietin in the treatment of head and neck tumour anaemia

Abstract.At the time of first diagnosis, patients with squamous cell carcinoma in the head and neck are often in the advanced stage of their disease, therefore surgery is not a viable option for treatment. These patients also present frequently a high grade of anaemia as a result of either the malignant process itself or of the following therapy. The incidence of anaemia and the need for transfusion depends on several factors, such as the type and intensity of radiotherapy and radio-chemotherapy. Multimode therapeutic concepts such as radio-chemotherapy are being applied with increasing frequency, resulting in an ever increasing need for transfusion with great effects on the patient's quality of life. Even more important to tumour patients is the role of the haemaglobin (Hb) value as a prognostic factor for survival and/or local tumour control. A large number of studies show that recombinant human erythropoietin (r-HuEPO) is effective in the treatment of tumour-induced anaemia and prevention and correction of chemotherapy and radiotherapy-induced anaemia. The simultaneous application of r-HuEPO with chemotherapy can prevent patients with head and neck tumours from developing anaemia or can reduce the extent of the anaemia and the need for transfusion. Comparable effects were observed both in patients undergoing platinum-based and non-platinum-based chemotherapy. The direct correlation between anaemia, tumour hypoxia and poor response to radio and/or chemotherapy has been clinically proven. Recombinant human erythropoietin administration improves the therapeutic outcome and the patients' prognosis.

How important is adequate radiotherapy for the long-term results of breast-conserving treatment?

The influence of radiotherapy dose parameters on longterm local control was studied in 134 clinical stage I-II breast cancer patients treated by tumorectomy and telecesium therapy during the 1960s. Recurrence in the breast was more frequent in patients receiving 75 Gy or less to the tumor bed (31 % versus 15 % for higher doses, p < 0.05), and weekly dose rates of less than 8 Gy/week were associated with increased local-regional failure (30% versus 15% for higher weekly doses, p < 0.01). The majority of local-regional failures were observed in the 53 patients having “inadequate” total or weekly radiotherapy doses ( 18 53 , 34% versus 9 81 , 11 %, p < 0.001). The importance of adequate radiotherapy applied to both older patients, as well as those younger than 40, who appear inherently to have a higher risk of local relapse. The mean interval to recurrence was markedly longer for inadequate radiotherapy (111 months, versus 75 months for adequate treatment), so that significant differences in local control became apparent only after 5 years. These results underscore the importance of radiotherapy technique in breast-conserving treatment, and suggest that an excessive reduction in the intensity of radiotherapy may result in an inordinate number of late local failures.

Current management and controversies. The patient's view.

The increasing curability of Hodgkin’s disease in children, now certainly >80% [1, 2], is continuously producing cured children, teenagers, and young adults to be returned to the ‘mainstream’ after an absence ranging from several months to almost a year. This high cure rate is achieved through a series of diagnostic tests including biopsy, multiple laboratory and imaging studies, and surgical staging followed by complicated chemotherapy and treatment with sophisticated radiation equipment. The high cure rate is blemished somewhat by the consequences of surgical staging (primarily the splenectomy), growth retardation in irradiated tissues, and the occurrence of second malignant tumors following intensive therapy with both treatment modalities. Adverse medical consequences of surgical staging have been reported in detail [3, 4], as have late effects of radiotherapy [5, 6] and the occurrence of second malignant tumors following combined modality therapy [7, 8]. These adverse effects are of great concern to both chemotherapists and radiotherapists, and have resulted in more selective use of the staging laparotomy, reductions in the intensity of radiotherapy, and use of less toxic chemotherapy regimens.