Initial report on feasibility of PET/CT-based image-guided moderate hypofractionated thoracic irradiation in node-positive non-small cell lung Cancer patients with poor prognostic factors and strongly diminished lung function: a retrospective analysis (original) (raw)
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The relationship between local dose and loss of function for irradiated lung
International Journal of Radiation Oncology*Biology*Physics, 2003
Purpose: To determine the relationship between the local radiation dose and the decrease in lung function associated with thoracic irradiation. Patients and Methods: Twenty-six patients treated with thoracic irradiation for lung cancer, for whom three-dimensional CT-based dosimetry was used in treatment planning, were evaluated with before and after treatment pulmonary function tests. Six patients were treated with radiotherapy alone (2.15 Gy daily fractions), and 20 patients with concurrent chemotherapy (cisplatin, etoposide) with hyperfractionated (HF) radiation therapy (1.2 Gy in twice-daily fractions). Eleven patients treated with concurrent HF chemoradiation also received the radioprotector amifostine. The normalized decrease in the diffusing capacity for carbon monoxide (DL CO ) was used as an objective measure of the change in lung function. The dose-volume histogram (DVH) data were used to estimate the local dose-response relationship for loss of DL CO . In each subvolume of lung, the loss in normalized DL CO was assumed to be a sigmoid function of dose, ranging from no loss at low doses to total loss at high doses. The whole-lung decrease in DL CO was modeled as the sum of the local declines in DL CO over all subvolumes. Nonlinear regression analysis was used to estimate the parameters of the local dose-response function. Results: The data are most consistent with a pronounced decrease in DL CO when the local dose (for radiotherapy alone or HF concurrent chemoradiation) exceeds 13 Gy (95% CI, 11-15 Gy). In patients who received amifostine in addition to HF radiotherapy with concurrent chemotherapy, this stepwise loss of DL CO occurred above 36 Gy (95% CI, 25-48 Gy). Grade 2 or higher pulmonary symptoms were associated with a DL CO loss of >30% (p ؍ 0.003). Conclusions: The decrease in pulmonary diffusion capacity correlates with the local dose to irradiated lung. Amifostine significantly reduces the loss in DL CO . A local dose-loss relationship for normalized DL CO can be extracted from DVH data. This relationship allows an estimate of the loss of function associated with a radiation treatment plan. Different plans can thus be compared without resort to an empiric DVH reduction algorithm. The very low (13 Gy) threshold for deterioration of DL CO suggests that it is better to treat a little normal lung to a high dose than to treat a lot to a low dose.
PO-0871: Radiation-induced lung damage: beyond dose-volume histogram analysis
Radiotherapy and Oncology, 2016
ESTRO 35 2016 ______________________________________________________________________________________________________ data suggested a better comfort for the patient for linacbased therapy, due to the shorter treatment time and the non-invasive immobilization system. Dosimetric data for the patients treated according to this protocol suggest a substantial balance between Gamma Knife and Linac EDGE treatments
Journal of Radiation Research, 2013
We evaluated the relationship between dosimetric parameters (DPs) and the incidence of radiation pneumonitis (RP) and investigated the feasibility of a proposed treatment planning technique with the potential of reducing RP in esophageal cancer patients treated with definitive chemoradiotherapy using extended fields. Patients and Methods: A total of 149 patients with locally advanced esophageal cancer were prospectively enrolled for extended-field radiotherapy (EFRT) to three-field regional lymphatics between September 2004 and June 2009. We retrospectively reviewed 86 consecutive patients who were treated with a total dose of 50.4 Gy (plus an optional 9 Gy boost) and were available for dose-volume analysis. Lung DPs of patients in the Grade 0-1 RP (RP G≤1) group and the Grade 2-5 RP (RP G≥2) group were compared. We compared the proposed plan with the conventional plan to 50.4 Gy on DPs for each case. Results: Of these 86 patients, 10 (12%) developed RP G≥2 (Grade 2, n = 2 patients; Grade 3, n = 3; Grade 4, n = 3; Grade 5, n = 2). The patients in the RP G≤1 group showed significantly lower (P < 0.05) V5 and V10 values for the whole lung compared with those in the RP G≥2 group. There were two advantages gained from the proposed plan for V5 (<55%) and V10 (< 37%) values and the conformity of the PTV. Conclusion: The increase in the volume of the lung exposed to low doses of EFRT was found to be associated with the incidence of RP. Our proposed plan is likely to reduce the incidence of RP.
American Journal of Clinical Oncology, 2008
Objective: To assess the incidence of clinical and imaging radiation pneumonitis (RP) in a cohort of patients treated with Ͼ30 Gy cumulative lung dose (CLD) using Y90 microspheres. Materials and Methods: Four hundred three patients were treated with Y90 microspheres during a 4-year period. Of these, 58 patients received Ͼ30 Gy CLD. Patients were followed for toxicities suggestive of imaging or clinical RP. Toxicities were graded using the Radiation Therapy Oncology Group/European Organisation for Research and Treatment of Cancer Late Radiation Morbidity Scoring Schema. Patients were also followed for survival from time of first treatment. Results: There were 44 men and 14 women. Forty-three patients had hepatocellular carcinoma (HCC), whereas 15 had liver metastases. Mean and median follow-up were 7.3 and 6.0 months, respectively. Mean lung shunt fraction was slightly greater in the patients with HCC versus metastases (20% vs. 16.7%, P ϭ 0.2308). The lifetime CLD for metastases and HCC groups were not statistically different (54.04 Gy vs. 48.44 Gy, P ϭ 0.4303). Forty-three of 53 patients demonstrated no lung imaging findings suggestive of pneumonitis. Imaging findings in 10 patients included pleural effusions, atelectasis, and ground glass attenuation. There were no cases of clinical or imaging RP. Survival varied depending on stage as well as single and CLD. None of the patient deaths were attributed to respiratory compromise. Conclusion: RP was not predicted using the currently used Y90 dosimetry models that assume uniform distribution in the lungs. Further investigation and dose escalation studies are required to more precisely define the radiation tolerance of lung parenchyma using this mode of therapy.
Journal of Thoracic Oncology, 2012
Introduction: To evaluate the influence of pretreatment pulmonary function (PF) on survival, early and late pulmonary toxicity after stereotactic body radiotherapy (SBRT) for early-stage non-small cell lung cancer. Methods: Four hundred eighty-three patients with 505 tumors of early-stage non-small cell lung cancer cT1-3 cN0 were treated with image-guided SBRT at five international institutions (1998-2010). Sixty-four percent of the tumors were biopsy-proven and 18Ffluorodeoxyglucose-positron emission tomography was performed for staging in 84%. Image-guided SBRT was performed with a median of three fractions to a median total dose of 54 Gy. Pretreatment PF was available for 423 patients, and 617 posttreatment PF tests from 270 patients were available. Results: A large variability of pretreatment PF was observed: the 90% range of forced expiratory volume in 1 second and diffusing capacity for carbon monoxide was 29 to 109% and 5.5 to 19.1 ml/min/mmHg, respectively. PF was significantly correlated with overall survival but not cause-specific survival: diffusing capacity for carbon monoxide of 11.2 ml/min/mmHg differentiated between 3-year overall survival of 66% and 42%. Radiation-induced pneumonitis grade ՆII occurred in 7% of patients and was not increased in patients with lower PF. A significant and progressive change of PF was observed after SBRT: PF decreased by 3.6% and 6.8% on average within 6 and 6 to 24 months after SBRT, respectively. Changes of PF after SBRT were significantly correlated with pre-treatment PF: PF improved for worst pretreatment PF and the largest loss was observed for best pretreatment PF. Conclusions: Image-guided SBRT is safe in terms of acute and chronic pulmonary toxicity even for patients with severe pulmonary comorbidities. SBRT should be considered as a curative treatment option for inoperable patients with pretreatment PF as reported in this study.
Radiotherapy and Oncology, 2009
Early stage non-small cell lung cancer Isodose-based planning Radiobiological analysis Normal tissue dose constraints a b s t r a c t Background and purpose: Help identify and define potential normal tissue dose constraints to minimize the mortality and morbidity of hypofractionated lung radiotherapy. Materials and methods: A method to generate isodose-based constraints and visually evaluate treatment plans, based on the published peer reviewed literature and the linear quadratic model, is presented. The radiobiological analysis assumes that the linear quadratic model is valid up to 28 Gy per fraction, the a/b ratio is 2 for the spinal cord and brachial plexus, 4 for pneumonitis, 4 or 10 for acute skin reactions depending on treatment length, and 3 for late complications in other normal tissues. A review of the literature was necessary to identify possible endpoints and normal tissue constraints for thoracic hypofractionated lung radiotherapy. Results: Preliminary normal tissue constraints to reduce mortality and morbidity were defined for organs at risk based upon hypofractionated lung radiotherapy publications. A modified dose nomenclature was introduced to facilitate the comparison of hypofractionated doses. Potential side effects from hypofractionated lung radiotherapy such as aortic dissection, neuropathy, and fatal organ perforation rarely seen in conventional treatments were identified. The isodose-based method for treatment plan analysis and normal tissue dose constraint simplification was illustrated. Conclusions: The radiobiological analysis based on the LQ method, biologically equivalent dose nomenclature, and isodose-based method proposed in this study simplifies normal tissue dose constraints and treatment plan evaluation. This may also be applied to extrathoracic hypofractionated radiotherapy. Prospective validation of these preliminary thoracic normal tissue dose constraints for hypofractionated lung radiotherapy is necessary.
International Journal of Radiation Oncology*Biology*Physics, 2001
To relate lung dose-volume histogram-based factors to symptomatic radiation pneumonitis (RP) in patients with lung cancer undergoing 3-dimensional (3D) radiotherapy planning. Between 1991 and 1999, 318 patients with lung cancer received external beam radiotherapy (RT) with 3D planning tools at Duke University Medical Center. One hundred seventeen patients were not evaluated for RP because of &amp;lt;6 months of follow-up, development of progressive intrathoracic disease making scoring of pulmonary symptoms difficult, or unretrievable 3D dosimetry data. Thus, 201 patients were analyzed for RP. Univariate and multivariate analyses were performed to test the association between RP and dosimetric factors (i.e., mean lung dose, volume of lung receiving &amp;gt;or=30 Gy, and normal tissue complication probability derived from the Lyman and Kutcher models) and clinical factors, including tobacco use, age, sex, chemotherapy exposure, tumor site, pre-RT forced expiratory volume in 1 s, weight loss, and performance status. Thirty-nine patients (19%) developed RP. In the univariate analysis, all dosimetric factors (i.e., mean lung dose, volume of lung receiving &amp;gt;or=30 Gy, and normal tissue complication probability) were associated with RP (p range 0.006-0.003). Of the clinical factors, ongoing tobacco use at the time of referral for RT was associated with fewer cases of RP (p = 0.05). These factors were also independently associated with RP according to the multivariate analysis (p = 0.001). Models predictive for RP based on dosimetric factors only, or on a combination with the influence of tobacco use, had a concordance of 64% and 68%, respectively. Dosimetric factors were the best predictors of symptomatic RP after external beam RT for lung cancer. Multivariate models that also include clinical variables were slightly more predictive.