Radiation pneumonitis and pulmonary fibrosis in non-small-cell lung cancer: pulmonary function, prediction, and prevention

Interleukin-17A antagonist attenuates radiation-induced lung injuries in mice

OBJECTIVE

To investigate the effect of interleukin-17A (IL-17A) antibodies on radiation-induced lung injuries in mice.

METHODS

The thorax of 135 mice were divided into Sham (n = 30), radiation control (RC, n = 35), treatment (n = 35, IL-17A-neutralizing antibody, 4 μg/mouse, IV, 4 days per month for 4 months) and placebo group (n = 35) before a single dose irradiation (15 Gy) to the thorax. Inflammation and collagen contents in the lung tissues were examined, and the concentration of IL-17A, TGF-β1, and IL-6 in bronchoalveolar lavage fluid (BALF) were measured. In another 50 animals, 180-day survival rate following the irradiation and treatment was calculated by Kaplan-Meier method.

RESULTS

Sixteen weeks after the irradiation and treatment, there was significant inflammatory cell infiltration and interstitial collagen depositions in the radiation control and placebo groups, whereas these changes were relatively mild in the treatment group. The percentage of grade II and III alveolitis in the treatment group (16%, P < .05) was lower than in the RC (72%) or placebo group (64%). The mean Aschcroft fibrosis scores were 2.8 (treatment group), 5.2 (RC), and 4.8 (placebo group), respectively. The scores of treatment group was lower than that of RC (P < .001) or placebo group (P < .001). The IL-17A, TGF-β, and IL-6 concentrations in the treatment group were lower than in the RC and placebo group (P < .01) following the irradiation. The 180-day mortality rate in the treatment group was lower than in the RC group 16.7% versus 75.0%, P < .05).

CONCLUSION

IL-17A antibody treatment alleviates radiation-induced pneumonitis and subsequent fibrosis, and improvise postirradiation survival.

Mapping metabolic changes associated with early Radiation Induced Lung Injury post conformal radiotherapy using hyperpolarized ¹³C-pyruvate Magnetic Resonance Spectroscopic Imaging

PURPOSE

Radiation Pneumonitis (RP) limits radiotherapy. Detection of early metabolic changes in the lungs associated with RP may provide an opportunity to adjust treatment before substantial toxicities occur. In this work, regional lactate-to-pyruvate signal ratio (lac/pyr) was quantified in rat lungs and heart following administration of hyperpolarized (13)C-pyruvate magnetic resonance imaging (MRI) at day 5, 10, 15 and 25-post conformal radiotherapy. These results were also compared to histology and blood analyses.

METHODS

The lower right lungs of 12 Sprague Dawley rats were irradiated in 2 fractions with a total dose of 18.5 Gy using a modified micro-CT system. Regional lactate and pyruvate data were acquired from three irradiated and three age-matched healthy rats at each time point on days 5, 10, 15 and 25-post radiotherapy. Arterial blood was collected from each animal prior to the (13)C-pyruvate injection and was analyzed for blood lactate concentration and arterial oxygen concentration (paO₂). Macrophage count was computed from the histology of all rat lungs.

RESULTS

A significant increase in lac/pyr was observed in both right and left lungs of the irradiated cohort compared to the healthy cohort for all time points. No increase in lac/pyr was observed in the hearts of the irradiated cohort compared to the hearts of the healthy cohorts. Blood lactate concentration and paO2 did not show a significant change between the irradiated and the healthy cohorts. Macrophage count in both right and left lungs was elevated for the irradiated cohort compared to the healthy cohort.

CONCLUSIONS

Metabolic changes associated with RP may be mapped as early as five days post conformal radiotherapy. Over the small sample size in each cohort, elevated macrophage count, consistent with early phase of inflammation was highly correlated to increases in lac/pyr in both the irradiated and unirradiated lungs. Further experiments with larger sample size may improve the confidence of this finding.

Management of normal tissue toxicity associated with chemoradiation (primary skin, esophagus, and lung)

Nearly one quarter of patients with lung cancer present with locally advanced disease where concurrent chemoradiotherapy is the current standard of care for patients with good performance status. Cisplatin-based concurrent chemoradiotherapy consistently showed an improvement in survival compared with sequential chemoradiotherapy, at the expense of an increase in the toxicity profile. Over the past decades, several encouraging biomarkers such as transforming growth factor-beta and radioprotective agents such as amifostine were studied but without reaching approval for patient care. We reviewed the prevalence and risk factors for different adverse effects associated with the combined chemoradiotherapy modality, especially dermatitis, mucositis, esophagitis, and pneumonitis. These adverse effects can further be divided into acute, subacute, and chronic. Dermatitis is usually rare and responds well to topical steroids and usual skin care. Acute esophagitis occurs in 30% of patients and is treated with proton pump inhibitors, promotility agents, local anesthetic, and dietary changes. Radiation pneumonitis is a subacute complication seen in 15% of patients and is usually managed with steroids. Chronic adverse effects such as radiation fibrosis and esophageal stricture occur approximately 6 months after completion of radiation therapy and are usually permanent. In this review, complications of chemoradiotherapy for patients with locally advanced lung cancer are delineated, and approaches to their management are described. Given that treatment interruption is associated with a worse outcome, patients are aggressively treated with a curative intent. Therefore, planning for treatment adverse effects improves patient tolerance, compliance, and outcome.

Do angiotensin-converting enzyme inhibitors reduce the risk of symptomatic radiation pneumonitis in patients with non-small cell lung cancer after definitive radiation therapy? Analysis of a single-institution database

PURPOSE

Preclinical studies have suggested that angiotensin-converting enzyme inhibitors (ACEIs) can mitigate radiation-induced lung injury. We sought here to investigate possible associations between ACEI use and the risk of symptomatic radiation pneumonitis (RP) among patients undergoing radiation therapy (RT) for non-small cell lung cancer (NSCLC).

METHODS AND MATERIALS

We retrospectively identified patients who received definitive radiation therapy for stages I to III NSCLC between 2004 and 2010 at a single tertiary cancer center. Patients must have received a radiation dose of at least 60 Gy for a single primary lung tumor and have had imaging and dosimetric data available for analysis. RP was quantified according to Common Terminology Criteria for Adverse Events, version 3.0. A Cox proportional hazard model was used to assess potential associations between ACEI use and risk of symptomatic RP.

RESULTS

Of 413 patients analyzed, 65 were using ACEIs during RT. In univariate analysis, the rate of RP grade ≥2 seemed lower in ACEI users than in nonusers (34% vs 46%), but this apparent difference was not statistically significant (P=.06). In multivariate analysis of all patients, ACEI use was not associated with the risk of symptomatic RP (hazard ratio [HR] = 0.66; P=.07) after adjustment for sex, smoking status, mean lung dose (MLD), and concurrent carboplatin and paclitaxel chemotherapy. Subgroup analysis showed that ACEI use did have a protective effect from RP grade ≥2 among patients who received a low (≤20-Gy) MLD (P<.01) or were male (P=.04).

CONCLUSIONS

A trend toward reduction in symptomatic RP among patients taking ACEIs during RT for NSCLC was not statistically significant on univariate or multivariate analyses, although certain subgroups may benefit from use (ie, male patients and those receiving low MLD). The evidence at this point is insufficient to establish whether the use of ACEIs does or does not reduce the risk of RP.

Molecular mechanisms and treatment of radiation-induced lung fibrosis

Radiation-induced lung fibrosis (RILF) is a severe side effect of radiotherapy in lung cancer patients that presents as a progressive pulmonary injury combined with chronic inflammation and exaggerated organ repair. RILF is a major barrier to improving the cure rate and well-being of lung cancer patients because it limits the radiation dose that is required to effectively kill tumor cells and diminishes normal lung function. Although the exact mechanism is unclear, accumulating evidence suggests that various cells, cytokines and regulatory molecules are involved in the tissue reorganization and immune response modulation that occur in RILF. In this review, we will summarize the general symptoms, diagnostics, and current understanding of the cells and molecular factors that are linked to the signaling networks implicated in RILF. Potential approaches for the treatment of RILF will also be discussed. Elucidating the key molecular mediators that initiate and control the extent of RILF in response to therapeutic radiation may reveal additional targets for RILF treatment to significantly improve the efficacy of radiotherapy for lung cancer patients.

Complications of thoracic radiotherapy

The issue of toxicity is a primary concern for chest irradiation, because it is a dose-limiting toxicity and because in some circumstances it can alleviate the survival benefit of radiation therapy. Potential acute and delayed side effects can compromise the patients' prognosis and generate significant morbidity. Here we review on chest complications of radiation therapy, with focus on cardiac and pulmonary radio-induced side effects. Most radiographic changes associated with thoracic irradiation are asymptomatic. However, chest irradiation generated by treatment of breast cancer, bronchopulmonary malignancies, or mediastinal lymphoma has been associated with a risk of acute radiation pneumonitis and late lung fibrosis. An increasing number of clinical studies suggest that some dosimetric factors (e.g. V20, V30, mean lung dose) should be considered for limiting the risk of lung toxicity. Improvements in radiation techniques as well as changes in indications, volumes and prescribed doses of radiation therapy should help to better spare lungs from irradiation and thus decreasing the risk of subsequent toxicity. Numerous other contributing factors should also be considered, such as chemotherapeutic agents, smoking, tumor topography, or intrinsic sensitivity. Cardiac toxicity is another clinically relevant issue in patients receiving radiation therapy for breast cancer or for lymphoma. This life threatening toxicity should be analyzed in the light of dosimetric factors (including low doses) but also associated systemic agents which almost carry a potential for additive toxicity toward myocardium or coronaries. A long-term follow-up of patients as well as an increasing knowledge of the underlying biological pathways involved in cardiac toxicity should help designing effective preventing strategies.

Influence of medical comorbidities on the presentation and outcomes of stage I-III non-small-cell lung cancer

BACKGROUND

Non-small-cell lung cancer presentation, treatment, and outcomes vary widely according to socioeconomic factors and other patient characteristics. To determine whether medical comorbidities account for these observations, we incorporated a validated medical comorbidity index into an analysis of patients diagnosed with stage I to III NSCLC.

PATIENTS AND METHODS

We performed a retrospective analysis of consecutive patients diagnosed with stage I to III NSCLC. Demographic, tumor, and comorbidity data were obtained from hospital tumor registries and individual patient records. The association between variables was assessed using multivariate logistic regression and survival analysis.

RESULTS

A total of 454 patients met criteria for analysis. The median age was 65 years, and 51% were men. Individuals with a higher Charlson Comorbidity Index (CCI) were significantly more likely to present with early stage (stage I-II) NSCLC than were patients with lower CCI (odds ratio, 1.72; 95% confidence interval, 1.14-2.63; P = .01), although this association lost statistical significance (P = .21) in a multivariate model. In multivariate logistic regression, overall survival remained associated with all variables: age, sex, race, insurance type, stage, histology, and CCI (P = .0007). The CCI was associated with survival for patients with early stage (P = .02) and locally advanced (P = .02) disease.

CONCLUSION

In this cohort of patients with stage I to III NSCLC, increasing comorbidity burden had a nonsignificant association with diagnosis at earlier disease stage. Although comorbidity burden was significantly associated with outcome for early stage and locally advanced disease, it did not account for survival differences based on multiple other patient and disease characteristics.

Development of radiation pneumopathy and generalised radiological changes after radiotherapy are independent negative prognostic factors for survival in non-small cell lung cancer patients

BACKGROUND AND PURPOSE

To investigate the risk factors for radiation pneumopathy (RP) and survival rate of non-small cell lung cancer patients with RP and generalised interstitial lung changes (gen-ILC).

MATERIAL AND METHODS

A total of 147 consecutive patients receiving curative radiotherapy were analysed. RP was graded according to Common Terminology Criteria for Adverse Events v. 3. Computed tomography images were assessed for the presence of gen-ILC after radiotherapy. Univariate and multivariate analyses were performed to identify significant factors.

RESULTS

Median follow-up was 16.2 months (range 1.4-58.6). Radiological changes after radiotherapy were confined to high dose irradiation volume in 111 patients, while 31 patients developed gen-ILC. Dosimetric parameters and level of C-reactive protein before radiotherapy were significantly associated with severe RP. Development of gen-ILC (p=0.008), as well as severe RP (p=0.03) had significant negative impact on patients' survival. These two factors remained significant in the multivariate analysis.

CONCLUSIONS

Severe radiation pneumopathy and generalised radiographic changes were significant independent prognostic factors for survival. More studies on pathophysiology of radiation induced damage are necessary to fully understand the mechanisms behind it.

Mitigation of radiation induced pulmonary vascular injury by delayed treatment with captopril

BACKGROUND AND OBJECTIVE

A single dose of 10 Gy radiation to the thorax of rats results in decreased total lung angiotensin-converting enzyme (ACE) activity, pulmonary artery distensibility and distal vascular density while increasing pulmonary vascular resistance (PVR) at 2 months post-exposure. In this study, we evaluate the potential of a renin-angiotensin system (RAS) modulator, the ACE inhibitor captopril, to mitigate this pulmonary vascular damage.

METHODS

Rats exposed to 10 Gy thorax only irradiation and age-matched controls were studied 2 months after exposure, during the development of radiation pneumonitis. Rats were treated, either immediately or 2 weeks after radiation exposure, with two doses of the ACE inhibitor, captopril, dissolved in their drinking water. To determine pulmonary vascular responses, we measured pulmonary haemodynamics, lung ACE activity, pulmonary arterial distensibility and peripheral vessel density.

RESULTS

Captopril, given at a vasoactive, but not a lower dose, mitigated radiation-induced pulmonary vascular injury. More importantly, these beneficial effects were observed even if drug therapy was delayed for up to 2 weeks after exposure.

CONCLUSIONS

Captopril resulted in a reduction in pulmonary vascular injury that supports its use as a radiomitigator after an unexpected radiological event such as a nuclear accident.

Predictors of radiation pneumonitis and pulmonary function changes after concurrent chemoradiotherapy of non-small cell lung cancer

Purpose

To evaluate the predictive factors of radiation pneumonitis (RP) and associated changes in pulmonary function after definitive concurrent chemoradiotherapy (CCRT) in patients with non-small cell lung cancer (NSCLC).

Materials and Methods

Medical records of 60 patients with NSCLC who received definitive CCRT were retrospectively reviewed. Dose volumetric (DV) parameters, clinical factors, and pulmonary function test (PFT) data were analyzed. RP was graded according to the CTCAE ver. 4.0. Percentage of lung volume that received a dose of threshold (Vdose) and mean lung dose (MLD) were analyzed for potential DV predictors. PFT changes were calculated as the difference between pre-RT and post-RT values at 3, 6, and 12 months after RT.

Results

Twenty-two patients (37%) developed grade ≥2 RP. Among clinical factors, tumor location in lower lobe was associated with RP. Among the DV parameters, only MLD >15 Gy was associated with grade ≥2 RP. There were statistically significant decreases in PFT at all points compared with pre-RT values in grade ≥2 RP group. MLD was associated with forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) changes at 6 and 12 months. V10 was associated with FVC changes at 12 months. V20 and V30 were associated with FEV1 changes at 6 months and FVC changes at 12 months.

Conclusion

After definitive CCRT in patients with NSCLC, MLD >15 Gy and lower lobe tumor location were predictors of grade ≥2 RP. Pulmonary functions were decreased after CCRT and the magnitude of changes was associated with DV parameters.

Foxm1 transcription factor is required for lung fibrosis and epithelial-to-mesenchymal transition

Alveolar epithelial cells (AECs) participate in the pathogenesis of pulmonary fibrosis, producing pro-inflammatory mediators and undergoing epithelial-to-mesenchymal transition (EMT). Herein, we demonstrated the critical role of Forkhead Box M1 (Foxm1) transcription factor in radiation-induced pulmonary fibrosis. Foxm1 was induced in AECs following lung irradiation. Transgenic expression of an activated Foxm1 transcript in AECs enhanced radiation-induced pneumonitis and pulmonary fibrosis, and increased the expression of IL-1β, Ccl2, Cxcl5, Snail1, Zeb1, Zeb2 and Foxf1. Conditional deletion of Foxm1 from respiratory epithelial cells decreased radiation-induced pulmonary fibrosis and prevented the increase in EMT-associated gene expression. siRNA-mediated inhibition of Foxm1 prevented TGF-β-induced EMT in vitro. Foxm1 bound to and increased promoter activity of the Snail1 gene, a critical transcriptional regulator of EMT. Expression of Snail1 restored TGF-β-induced loss of E-cadherin in Foxm1-deficient cells in vitro. Lineage-tracing studies demonstrated that Foxm1 increased EMT during radiation-induced pulmonary fibrosis in vivo. Foxm1 is required for radiation-induced pulmonary fibrosis by enhancing the expression of genes critical for lung inflammation and EMT.

Melatonin reduces X-ray radiation-induced lung injury in mice by modulating oxidative stress and cytokine expression

PURPOSE

The modification of radiation-induced lung injuries by melatonin was studied by measuring changes in oxidative stress, cytokine expression and histopathology in the lung tissue of mice following irradiation.

MATERIALS AND METHODS

The thoraces of C57BL/6 mice were exposed to a single X-ray radiation dose of 12 Gy with or without 200 mg/kg of melatonin pretreatment. The level and localization of transforming growth factor (TGF)-β1 protein were measured using an enzyme-linked immunosorbent assay (ELISA) method and immunohistochemical staining, respectively. Real-time quantitative polymerase chain reaction (PCR) was established to evaluate the relative mRNA expression levels of TGF-β1, tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6.

RESULTS

Malondialdehyde (MDA) levels increased after irradiation and then significantly reduced (1.9-fold) under melatonin treatment. Changes in superoxide dismutase (SOD) and catalase activities, as well as glutathione (GSH) levels, after irradiation were significantly reduced by melatonin, including a notable 5.4-fold difference in catalase activity. We observed increased expression of TGF-β1 and TNF-α after irradiation and a significant reduction in the elevation of their expression by melatonin treatment. Furthermore, irradiation-induced histopathologic alterations were obviously abated in the melatonin-pretreated mice.

CONCLUSIONS

The present results suggest that melatonin reduces radiation-induced lung injury via a significant reduction of oxidative stress and of the production of cytokines, such as TGF-β1 and TNF-α, the production of which increased following lung irradiation.

Radiation pneumonitis in breast cancer patients who received radiotherapy using the partially wide tangent technique after breast conserving surgery

Purpose

We assessed the risk of radiation pneumonitis (RP) in terms of dosimetric parameters in breast cancer patients, who received radiotherapy using the partially wide tangent technique (PWT), following breast conservation surgery (BCS).

Methods

We analyzed the data from 100 breast cancer patients who underwent radiotherapy using PWT. The entire breast, supraclavicular lymph node, and internal mammary lymph node (IMN) were irradiated with 50.4 Gy in 28 fractions. RP was scored on a scale of 0 to 5, based on Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer toxicity criteria. The dosimetric parameters, used in analysis for the ipsilateral lung, were the mean lung dose (MLD), V₅ (percentage of lung volume that received a dose of 5 Gy or more)-V₅₀, and normal tissue complication probability (NTCP).

Results

Of the 100 patients, three suffered from symptomatic RP (symptom grade ≥2), but were relieved by supportive care. The risk of RP was not correlated with the treatment regimen. RP associated mostly with asymptomatic minimal pulmonary radiologic change or mild dry cough developed more frequently in the group with MLD ≥20.5 Gy or NTCP ≥23% than in the group with MLD <20.5 Gy and NTCP <23% (48.6% vs. 25.4%, p=0.018).

Conclusion

Dosimetric parameters of MLD and NTCP were correlated with the incidence of RP, but the clinical impact was minimal. We suggest that PWT is a safe technique for the treatment of IMN for BCS patients with low risk of symptomatic RP.

Multimodal treatment of esophageal cancer

BACKGROUND

The treatment of localized esophageal cancer has been debated controversially over the past decades. Neoadjuvant treatment was used empirically, but evidence was limited due to the lack of high-quality confirmatory studies. Meanwhile, data have become much clearer due to recently published well-conducted randomized controlled trials and meta-analyses.

METHODS

Neoadjuvant and perioperative platinum fluoropyrimidine-based combination chemotherapy has now an established role in the treatment of stage II and stage III esophageal adenocarcinoma and cancer of the esophago-gastric junction. Neoadjuvant chemoradiation is now the standard of care for treating stage II and stage III esophageal squamous cell cancer and can also be considered for treating esophageal adenocarcinoma.

RESULTS

Patients with esophageal squamous cell cancer treated with definitive chemoradiation achieve comparable long-term survival compared with surgery. Short-term mortality is less with chemoradiation alone, but local tumor control is significantly better with surgery.

CONCLUSION

This expert review article outlines current data and literature and delineates recommendable treatment guidelines for localized esophageal cancer.

Image-guided robotic stereotactic radiation therapy with fiducial-free tumor tracking for lung cancer

Purpose

Stereotactic body radiation therapy (SBRT) for early-stage lung cancer can be achieved with several methods: respiratory gating, body frame, or real-time target and motion tracking. Two target tracking methods are currently available with the CyberKnife® System: the first one, fiducial tracking, requires the use of radio-opaque markers implanted near or inside the tumor, while the other, Xsight® Lung Tracking System, (XLTS) is fiducial-free. With XLTS, targeting is synchronized directly with target motion, which occurs due to respiration. While the former method (fiducial tracking) is well documented, the clinical relevance of the latter (tracking without fiducials) has never been well described to this date.

Patients and Methods

A study was performed at our department for each patient treated for lung cancer with CyberKnife using XLTS. Selection criteria were: primary or recurring T1 or T2 stage non-small-cell lung cancer (NSCLC) with 15–60 mm tumor size. Initial staging included CT-Scan and FDG-PET.

Results

Fifty-one patients not amenable to surgery were treated with XLTS. Median follow-up was 15 months (range, 5–30 months). Median tumor size was 24 mm (range, 15–60 mm). Median total dose was 60 Gy (36–60 Gy) in three fractions. Actuarial overall survival was 85.5% (95% CI = 74.5–96%) at 1 year and 79.4% (95% CI = 64–94.8%) at 2 years. Actuarial local control rate was 92% (95% CI = 84–99%) at one1 year and 86% (95% CI = 75–97%) at 2 years.

Conclusion

Local control and overall survival rates were similar to previous reports that used fiducials for tumor tracking. Toxicity was lower than most studies since tumor tracking did not require fiducial implantion. This fiducial-free method for respiratory motion tracking is a valid option for the most fragile patients.

Protection against acute radiation-induced lung injury: a novel role for the anti-angiogenic agent Endostar

Radiotherapy is commonly used to treat thoracic malignancies, but often causes severe lung injury. Currently there are no effective protective strategies against radiation-induced lung injury (RILI). This study aimed to evaluate the ability of an angiogenesis antagonist, Endostar, against RILI, and the underlying mechanism in a mouse model. A total of 108 C57BL/6 female mice were randomized into 4 groups (n=27): i) control group; ii) Endostar group, animals were administered 7.75 ml/kg Endostar through intraperitoneal injection; iii) irradiation group, RILI was induced by exposing the animals to a single external irradiation on the thoraces (6 MV X-ray, 12 Gy); and iv) irradiation plus Endostar group, animals were subjected to Endostar treatment and irradiation as in groups 2 and 3. A total of 3 animals from each of the 4 groups were sacrificed at 1, 6, 12, 24 and 72 h and at 2, 4, 8 and 24 weeks following treatment. Clinical signs and pathology of RILI were examined. The expression of transforming growth factor-β 1 (TGF-β1) in lungs was analyzed by real-time quantitative polymerase chain reaction (RT-QPCR) and immunohistochemistry. Compared with the control group, irradiation induced evident interstitial edema and a significant increase in inflammatory cells in the lungs (P<0.05). Correlated with these changes, a notable increase in TGF-β1 mRNA level and a robust increase in TGF-β1 immunoreactivity were observed in lung tissues in a time-dependent manner following irradiation (P<0.05). Endostar administration effectively attenuated the magnitude of the increase in inflammatory cells as well as the elevation of TGF-β1 expression in lung tissues after RILI (P<0.05). In conclusion, radiation induced an increased expression of the inflammatory mediator TGF-β1 and the associated pathogenesis in the lung, while Endostar was able to at least partially attenuate RILI through downregulating the expression of TGF-β1 in mice. Our findings suggest that Endostar may be a novel protective agent against RILI.

Changes in pulmonary function after three-dimensional conformal radiotherapy, intensity-modulated radiotherapy, or proton beam therapy for non-small-cell lung cancer

PURPOSE

To investigate the extent of change in pulmonary function over time after definitive radiotherapy for non-small-cell lung cancer (NSCLC) with modern techniques and to identify predictors of changes in pulmonary function according to patient, tumor, and treatment characteristics.

PATIENTS AND METHODS

We analyzed 250 patients who had received ≥ 60 Gy radio(chemo)therapy for primary NSCLC in 1998-2010 and had undergone pulmonary function tests before and within 1 year after treatment. Ninety-three patients were treated with three-dimensional conformal radiotherapy, 97 with intensity-modulated radiotherapy, and 60 with proton beam therapy. Postradiation pulmonary function test values were evaluated among individual patients compared with the same patient's preradiation value at the following time intervals: 0-4 (T1), 5-8 (T2), and 9-12 (T3) months.

RESULTS

Lung diffusing capacity for carbon monoxide (DLCO) was reduced in the majority of patients along the three time periods after radiation, whereas the forced expiratory volume in 1 s per unit of vital capacity (FEV1/VC) showed an increase and decrease after radiation in a similar percentage of patients. There were baseline differences (stage, radiotherapy dose, concurrent chemotherapy) among the radiation technology groups. On multivariate analysis, the following features were associated with larger posttreatment declines in DLCO: pretreatment DLCO, gross tumor volume, lung and heart dosimetric data, and total radiation dose. Only pretreatment DLCO was associated with larger posttreatment declines in FEV1/VC.

CONCLUSIONS

Lung diffusing capacity for carbon monoxide is reduced in the majority of patients after radiotherapy with modern techniques. Multiple factors, including gross tumor volume, preradiation lung function, and dosimetric parameters, are associated with the DLCO decline. Prospective studies are needed to better understand whether new radiation technology, such as proton beam therapy or intensity-modulated radiotherapy, may decrease the pulmonary impairment through greater lung sparing.

The features of radiation induced lung fibrosis related with dosimetric parameters

BACKGROUND AND PURPOSE

Radiation induced lung fibrosis (RILF) is a major complication after lung irradiation and is very important for long term quality of life and could result in fatal respiratory insufficiency. However, there has been little information on dosimetric parameters for radiotherapy planning in the aspect of RILF. The features of RILF related with dosimetric parameters were evaluated.

METHODS AND MATERIALS

Forty-eight patients with non-small cell lung carcinoma who underwent post-operative radiation therapy (PORT) without adjuvant chemotherapy were analyzed. The degree of lung fibrosis was estimated by fibrosis volume and the dosimetric parameters were calculated from the plan of 3-dimensional conformal radiotherapy.

RESULTS

The fibrosis volume and V-dose as dosimetric parameters showed significant correlation and the correlation coefficient ranged from 0.602 to 0.683 (P<0.01). The degree of the correlation line was steeper as the dose increase and threshold dose was not found. Mean lung dose (MLD) showed strong correlation with fibrosis volume (correlation coefficient = 0.726, P<0.01).

CONCLUSIONS

The fibrosis volume is continuously increased with V-dose as the reference dose increases. MLD is useful as a single parameter for comparing rival plans in the aspect of RILF.

ICRP publication 118: ICRP statement on tissue reactions and early and late effects of radiation in normal tissues and organs--threshold doses for tissue reactions in a radiation protection context

This report provides a review of early and late effects of radiation in normal tissues and organs with respect to radiation protection. It was instigated following a recommendation in Publication 103 (ICRP, 2007), and it provides updated estimates of 'practical' threshold doses for tissue injury defined at the level of 1% incidence. Estimates are given for morbidity and mortality endpoints in all organ systems following acute, fractionated, or chronic exposure. The organ systems comprise the haematopoietic, immune, reproductive, circulatory, respiratory, musculoskeletal, endocrine, and nervous systems; the digestive and urinary tracts; the skin; and the eye. Particular attention is paid to circulatory disease and cataracts because of recent evidence of higher incidences of injury than expected after lower doses; hence, threshold doses appear to be lower than previously considered. This is largely because of the increasing incidences with increasing times after exposure. In the context of protection, it is the threshold doses for very long follow-up times that are the most relevant for workers and the public; for example, the atomic bomb survivors with 40-50years of follow-up. Radiotherapy data generally apply for shorter follow-up times because of competing causes of death in cancer patients, and hence the risks of radiation-induced circulatory disease at those earlier times are lower. A variety of biological response modifiers have been used to help reduce late reactions in many tissues. These include antioxidants, radical scavengers, inhibitors of apoptosis, anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, growth factors, and cytokines. In many cases, these give dose modification factors of 1.1-1.2, and in a few cases 1.5-2, indicating the potential for increasing threshold doses in known exposure cases. In contrast, there are agents that enhance radiation responses, notably other cytotoxic agents such as antimetabolites, alkylating agents, anti-angiogenic drugs, and antibiotics, as well as genetic and comorbidity factors. Most tissues show a sparing effect of dose fractionation, so that total doses for a given endpoint are higher if the dose is fractionated rather than when given as a single dose. However, for reactions manifesting very late after low total doses, particularly for cataracts and circulatory disease, it appears that the rate of dose delivery does not modify the low incidence. This implies that the injury in these cases and at these low dose levels is caused by single-hit irreparable-type events. For these two tissues, a threshold dose of 0.5Gy is proposed herein for practical purposes, irrespective of the rate of dose delivery, and future studies may elucidate this judgement further.

Quantitative study of lung perfusion SPECT scanning and pulmonary function testing for early radiation-induced lung injury in patients with locally advanced non-small cell lung cancer

Radiation lung injury is a common side-effect of pulmonary radiotherapy. The aim of this study was to quantitatively assess early changes in lung perfusion single photon emission computed tomography (SPECT) scanning and pulmonary function testing (PFT) prior to and after intensity modulated radiotherapy (IMRT) for patients suffering from locally advanced non-small cell lung cancer (LANSCLC). Twenty patients with LANSCLC received lung perfusion SPECT scanning and PFT prior to IMRT and immediately after IMRT. Lung perfusion index (LPI) was calculated after the quantification of perfusion SPECT images. The LPI of the two groups was analyzed by matched t-test. The radioactive count of each layer of single lung was added to obtain the sum of the irradiated area. The percentage of the irradiated area of single lung was calculated. Linear correlation analysis was carried out between the percentage of the irradiated area and LPI in order to verify the validity of LPI. In this study, LPI and the percentage of the irradiated area of single lung exhibited an excellent correlation either prior to or after IMRT (r=0.820 and r=0.823, respectively; p<0.001). There was no statistically significant difference between pre-IMRT LPI and post-IMRT LPI (p=0.135). LPI in the group receiving a radical dose had no statistically significant difference (p=0.993), however, it showed a statistically significant difference in the group receiving a non-radical dose (p=0.025). In the non-radical dose group, the post-IMRT LPI was larger compared to pre-IMRT. None of the parameters of PFT exhibited a statistically significant difference prior to and after IMRT (p>0.05). The quantitative method of lung perfusion SPECT scanning can be used to evaluate changes in perfusion early in patients receiving a non-radical dose (BED ≤126,500 cGy) IMRT. Evaluating early changes in global lung function using the current method of PFT is difficult, since time can be a contributing factor for radiation-induced lung injury.

Decreased risk of radiation pneumonitis with incidental concurrent use of angiotensin-converting enzyme inhibitors and thoracic radiation therapy

PURPOSE

Angiotensin-converting enzyme (ACE) inhibitors have been shown to mitigate radiation-induced lung injury in preclinical models. The aim of this study was to evaluate whether ACE inhibitors decrease the risk of radiation pneumonitis in lung cancer patients receiving thoracic irradiation.

METHODS AND MATERIALS

Patients with Stage I through III small-cell and non-small-cell lung cancer treated definitively with radiation from 2004-2009 at the Clement J. Zablocki Veterans Affairs Medical Center were retrospectively reviewed. Acute pulmonary toxicity was quantified within 6 months of completion of treatment according to the Common Terminology Criteria for Adverse Events version 4. The use of ACE inhibitors, nonsteroidal anti-inflammatory drugs, inhaled glucocorticosteroids, statins, and angiotensin receptor blockers; dose-volume histogram parameters; and patient factors were assessed for association with Grade 2 or higher pneumonitis.

RESULTS

A total of 162 patients met the criteria for inclusion. The majority of patients had Stage III disease (64%) and received concurrent chemotherapy (61%). Sixty-two patients were identified as ACE inhibitor users (38%). All patients had acceptable radiation plans based on dose-volume histogram constraints (V20 [volume of lung receiving at least 20 Gy] ≤37% and mean lung dose ≤20 Gy) with the exception of 2 patients who did not meet both criteria. Grade 2 or higher pulmonary toxicity occurred in 12 patients (7.4%). The rate of Grade 2 or higher pneumonitis was lower in ACE inhibitor users vs. nonusers (2% vs. 11%, p = 0.032). Rates of Grade 2 or higher pneumonitis were significantly increased in patients aged greater than 70 years (16% vs. 2%, p = 0.005) or in whom V5 (volume of lung receiving at least 5 Gy) was 50% or greater (13% vs. 4%, p = 0.04). V10 (volume of lung receiving at least 10 Gy), V20, V30 (volume of lung receiving at least 30 Gy), and mean lung dose were not independently associated with Grade 2 or higher pneumonitis.

CONCLUSION

ACE inhibitors may decrease the incidence of radiation pneumonitis in patients receiving thoracic radiation for lung cancer. These findings are consistent with preclinical evidence and should be prospectively evaluated.

Comparison of clinical, tumour-related and dosimetric factors in grade 0-1, grade 2 and grade 3 radiation pneumonitis after stereotactic body radiotherapy for lung tumours

OBJECTIVE

The aim of this study was to investigate significant clinical, tumour-related and dosimetric factors among patients with grade 0-1, grade 2 and grade 3 radiation pneumonitis (RP) after stereotactic body radiotherapy (SBRT) for lung tumours.

METHODS

Patients (n=128) with a total of 133 lung tumours treated with SBRT of 50 Gy in 5 fractions were analysed. RP was graded according to the Common Terminology Criteria for Adverse Events v.3.0. Significant factors were identified by univariate and multivariate analyses. Threshold dose-volume histograms (DVHs) were constructed to identify the incidence of RP.

RESULTS

The median follow-up period was 12 months (range, 6-45 months). In univariate analyses, gender, operability, forced expiratory volume in 1 s (FEV1), internal target volume, lung volumes treated with doses >5-30 Gy (V5-30) and mean lung dose were significant factors differentiating between grade 0-1 and grade 2 RP, and V15-30 were significant factors differentiating between grade 2 and grade 3. However, no factors were significant between grade 0-1 and grade 3 RP. Multivariate analysis showed that female gender, high FEV1 and high V15 were significant factors differentiating between grade 0-1 and grade 2 RP. Threshold DVH curves were created based on ≤5% and ≤15% risk of grade 2 RP among patients with grade 0-2 RP.

CONCLUSIONS

Grade 0-2 RP was dose-volume dependent, and female gender and high FEV1 were significant predictive clinical factors for grade 2 RP among patients with grade 0-2 RP. However, incidences of V15-30 in grade 3 RP were significantly lower than those in grade 2 RP, and no significant clinical or tumour-related factors were found. Further studies are needed to identify the mechanism underlying the development of grade 3 RP after SBRT for lung tumours.

Challenges scoring radiation pneumonitis in patients irradiated for lung cancer

BACKGROUND AND PURPOSE

To quantify uncertainties in scoring radiation pneumonitis.

MATERIALS AND METHODS

Records of 434 patients irradiated for lung cancer from 2000 to 2010 were retrospectively reviewed; IRB-approved study. From these, 121 received ≥ 60 Gy for non-small cell lung cancer (NSCLC) with ≥ 6 months follow-up. Patients where the physicians were uncertain of the diagnosis due to confounding factors were deemed "hard to score". Subgroups were defined based on lung dosimetric parameters, and frequencies in different subgroups were compared via Fisher's exact test.

RESULTS

21/121 of patients were considered to have pneumonitis; median follow 17 months. Of these, 10/21 were "hard to score"; reasons including acute COPD exacerbation, infection, and tumor progression. "Hard to score" pneumonitis was slightly more common in patients with a COPD history (15%) vs. without COPD (4%) (p=0.05); and with a pre-RT FEV1<1.7 L (16%) vs. ≥1.7 L (4%) (p=0.09). Rates of "unambiguous" pneumonitis trended to be non-significantly slightly higher in patients higher mean lung doses, V5, and V30.

CONCLUSION

Radiation pneumonitis occurred in 17% of patients undergoing RT for NSCLC; with diagnostic uncertainty in 48% of these. Poor pre-RT pulmonary function increases the rate of "hard to score" pneumonitis. Dosimetric parameters are slightly better related to "unambiguous" than "hard to score" pneumonitis, as expected.

Association of computed tomography-detected pulmonary interstitial changes with severe radiation pneumonitis for patients treated with thoracic radiotherapy

We evaluated associations of interstitial changes with radiation pneumonitis (RP) for patients treated with thoracic radiotherapy. Between 2005 and 2009, patients who received thoracic radiotherapy of 40 Gy or more for lung cancer or thymic tumors and were followed-up for more than 6 months were eligible for this study. Possible risk factors for RP included the presence of interstitial changes on computed tomography before radiotherapy, and elevated C-reactive protein (CRP) and lactate dehydrogenase (LDH) levels; these were compared with the incidences of severe RP. A total of 106 patients were included. The incidences of RP were 4 (4%), 0 (0%), and 5 (5%) for grades 3, 4, and 5, respectively. For those with interstitial changes, the incidence of RP ≥ grade 3 was significantly increased from 3% (2/79) to 26% (7/27) (p < 0.001). CRP and LDH levels were also associated with increased RP, as were pulmonary emphysema and performance status ≥ 2. Among 91 patients with RP ≥ grade 1, RP grade ≥ 3 occurred significantly earlier than grades 1 and 2. In conclusion, pulmonary interstitial changes, LDH and CRP levels, pulmonary emphysema, and performance status ≥ 2 were significantly associated with RP ≥ grade 3. RP grade ≥ 3 occurred significantly earlier than grades 1 and 2. The early appearance of interstitial changes requires careful management due to the possibility of severe RP.

Angiotensin converting enzyme inhibitors mitigate collagen synthesis induced by a single dose of radiation to the whole thorax

Our long-term goal is to use angiotensin converting enzyme (ACE) inhibitors to mitigate the increase in lung collagen synthesis that is induced by irradiation to the lung, which could result from accidental exposure or radiological terrorism. Rats (WAG/RijCmcr) were given a single dose of 13 Gy (dose rate of 1.43 Gy/min) of X-irradiation to the thorax. Three structurally-different ACE inhibitors, captopril, enalapril and fosinopril were provided in drinking water beginning 1 week after irradiation. Rats that survived acute pneumonitis (at 6-12 weeks) were evaluated monthly for synthesis of lung collagen. Other endpoints included breathing rate, wet to dry lung weight ratio, and analysis of lung structure. Treatment with captopril (145-207 mg/m(2)/day) or enalapril (19-28 mg/m(2)/day), but not fosinopril (19-28 mg/m(2)/day), decreased morbidity from acute pneumonitis. Lung collagen in the surviving irradiated rats was increased over that of controls by 7 months after irradiation. This increase in collagen synthesis was not observed in rats treated with any of the three ACE inhibitors. Analysis of the lung morphology at 7 months supports the efficacy of ACE inhibitors against radiation-induced fibrosis. The effectiveness of fosinopril against fibrosis, but not against acute pneumonitis, suggests that pulmonary fibrosis may not be a simple consequence of injury during acute pneumonitis. In summary, three structurally-different ACE inhibitors mitigate the increase in collagen synthesis 7 months following irradiation of the whole thorax and do so, even when therapy is started one week after irradiation.

Subclinical vitamin A deficiency does not increase development of tumors in irradiated or unirradiated lungs

Cancer patients often have subclinical vitamin A deficiencies and low vitamin A lung levels. Previous studies showed that subclinical vitamin A deficiency increased the severity of pneumonitis induced by whole-lung irradiation in rats. Many studies have shown that lung irradiation increases the number of lung tumors developing from intravenously injected tumor cells in mice. We examined the impact of vitamin A deficiency on the development of lung metastases from a highly metastatic syngeneic rat rhabdomyosarcoma in normal rats and rats receiving prior lung irradiation. Weanling female WAGrijY rats were randomized to receive either a diet lacking both vitamin A and beta-carotene or a control diet. After five weeks, the deficient diet significantly decreased levels of retinol in the lung and liver but not in the serum, modeling the tissue and blood levels seen in prior studies of patients with subclinical vitamin A inadequacy. The vitamin A-deficient diet did not alter the number of lung tumors developing from intravenously injected tumor cells in unirradiated rats. Whole-lung irradiation produced dose-dependent increases in the number of lung tumors developing from tumor cells injected intravenously one or 29 d after irradiation. Vitamin A deficiency did not alter these dose-response curves, indicating that the more intense radiation-induced pneumonitis seen previously in vitamin A-deficient rats did not alter the enhancement of metastases produced by whole-lung irradiation. Moreover, inadequate vitamin A intake did not influence the growth of tumors implanted subcutaneously or increase the number or size of the spontaneous lung metastases developing from these subcutaneous tumors. Thus, although low vitamin A status influences the development of lung injury and is considered a possible modifiable risk factor increasing risk of primary cancer, it did not affect the growth of subcutaneous tumors or increase the development of artificial or spontaneous lung metastases in this rat model.

Factors predicting radiation pneumonitis in locally advanced non-small cell lung cancer

Purpose

Thoracic radiotherapy is a major treatment modality of stage III non-small cell lung cancer. The normal lung tissue is sensitive to radiation and radiation pneumonitis is the most important dose-limiting complication of thoracic radiation therapy. This study was performed to identify the clinical and dosimetric parameters related to the risk of radiation pneumonitis after definitive radiotherapy in stage III non-small cell cancer patients.

Materials and Methods

The medical records were reviewed for 49 patients who completed definitive radiation therapy for locally advanced non-small cell lung cancer from August 2000 to February 2010. Radiation therapy was delivered with the daily dose of 1.8 Gy to 2.0 Gy and the total radiation dose ranged from 50.0 Gy to 70.2 Gy (median, 61.2 Gy). Elective nodal irradiation was delivered at a dose of 45.0 Gy to 50.0 Gy. Seven patients (14.3%) were treated with radiation therapy alone and forty two patients (85.7%) were treated with chemotherapy either sequentially or concurrently.

Results

Twenty-five cases (51.0%) out of 49 cases experienced radiation pneumonitis. According to the radiation pneumonitis grade, 10 (20.4%) were grade 1, 9 (18.4%) were grade 2, 4 (8.2%) were grade 3, and 2 (4.1%) were grade 4. In the univariate analyses, no clinical factors including age, sex, performance status, smoking history, underlying lung disease, tumor location, total radiation dose and chemotherapy were associated with grade ≥2 radiation pneumonitis. In the subgroup analysis of the chemotherapy group, concurrent rather than sequential chemotherapy was significantly related to grade ≥2 radiation pneumonitis comparing sequential chemotherapy. In the univariate analysis with dosimetric factors, mean lung dose (MLD), V₂₀, V₃₀, V₄₀, MLDipsi, V₂₀ipsi, V₃₀ipsi, and V₄₀ipsi were associated with grade ≥2 radiation pneumonitis. In addition, multivariate analysis showed that MLD and V30 were independent predicting factors for grade ≥2 radiation pneumonitis.

Conclusion

Concurrent chemotherapy, MLD and V₃₀ were statistically significant predictors of grade ≥2 radiation pneumonitis in patients with stage III non-small cell lung cancer undergoing definitive radiotherapy. The cutoff values for MLD and V₃₀ were 16 Gy and 18%, respectively.

Correlation of dosimetric parameters obtained with the analytical anisotropic algorithm and toxicity of chest chemoradiation in lung carcinoma

The purpose of this study was to analyze and revisit toxicity related to chest chemoradiotherapy and to correlate these side effects with dosimetric parameters obtained using analytical anisotropic algorithm (AAA) in locally unresectable advanced lung cancer. We retrospectively analyzed data from 47 lung cancer patients between 2005 and 2008. All received conformal 3D radiotherapy using high-energy linear accelerator plus concomitant chemotherapy. All treatment planning data were transferred into Eclipse 8.05 (Varian Medical Systems, Palo Alto, CA) and dosimetric calculations were performed using AAA. Thirty-three patients (70.2%) developed acute pneumopathy after radiotherapy (grades 1 and 2). One patient (2.1%) presented with grade 3 pneumopathy. Thirty-one (66%) presented with grades 1-2 lung fibrosis, and 1 patient presented with grade 3 lung fibrosis. Thirty-four patients (72.3%) developed grade 1-2 acute oesophagic toxicity. Four patients (8.5%) presented with grades 3 and 4 dysphagia, necessitating prolonged parenteral nutrition. Median prescribed dose was 64 Gy (range 50-74) with conventional fractionation (2 Gy per fraction). Dose-volume constraints were respected with a median V20 of 23.5% (maximum 34%) and a median V30 of 17% (maximum 25%). The median dose delivered to healthy contralateral lung was 13.1 Gy (maximum 18.1 Gy). At univariate analysis, larger planning target volume and V20 were significantly associated with the probability of grade ≥2 radiation-induced pneumopathy (p = 0.022 and p = 0.017, respectively). No relation between oesophagic toxicity and clinical/dosimetric parameters could be established. Using AAA, the present results confirm the predictive value of the V20 for lung toxicity as already demonstrated with the conventional pencil beam convolution approach.

Early changes in L-arginine-nitric oxide metabolic pathways in response to the whole-body gamma irradiation of rats

PURPOSE

Nitric oxide (NO), a reactive radical, is formed in higher amounts from L-arginine by inducible NO synthase (iNOS) during early response to ionizing radiation presumably as a part of signal transduction pathways. This study investigated the changes in L-arginine-NO metabolic pathways within a 24-hour period after whole-body gamma irradiation of rats with the range of low to supra-lethal doses.

MATERIALS AND METHODS

Young adult female Wistar rats received either 0-50 Gy whole-body irradiation or an intraperitoneal injection of bacterial lipopolysaccharide (LPS, 10 mg/kg). Exhaled NO was monitored using chemiluminiscence, nitrite + nitrate (NO(x)) and L-arginine were assayed by high-performance liquid chromatography, and expression of iNOS was determined using Western blot.

RESULTS

Irradiation resulted in a dose-dependent increase of plasma NO(x) to maximum levels which were 4-fold higher compared to controls (p < 0.001). The NO(x) levels increased less in the bronchoalveolar lavage fluid (BAL) (1.7-fold, p < 0.001) and liver homogenate (2.5-fold, p < 0.05), respectively, and were dose-independent. Exhaled NO, lung NO(x), plasma and BAL L-arginine, and the expression of iNOS in lung and liver tissues of irradiated rats and controls were similar. LPS caused a considerable increase (p < 0.001) in exhaled NO (61-fold), NO(x) levels (plasma 34-fold, BAL 6-fold, lung 5-fold, liver 4-fold), and in iNOS expression, respectively.

CONCLUSION

In contrast to the LPS treatment of rats, the radiation-induced changes in L-arginine-NO metabolic pathways are modest, particularly in the airways and lungs. Noninvasive measurement of exhaled NO within a 24-h period following the exposure of rats to ionizing radiation has no value for biodosimetry.

Functional polymorphisms of base excision repair genes XRCC1 and APEX1 predict risk of radiation pneumonitis in patients with non-small cell lung cancer treated with definitive radiation therapy

PURPOSE

To explore whether functional single nucleotide polymorphisms (SNPs) of base-excision repair genes are predictors of radiation treatment-related pneumonitis (RP), we investigated associations between functional SNPs of ADPRT, APEX1, and XRCC1 and RP development.

METHODS AND MATERIALS

We genotyped SNPs of ADPRT (rs1136410 [V762A]), XRCC1 (rs1799782 [R194W], rs25489 [R280H], and rs25487 [Q399R]), and APEX1 (rs1130409 [D148E]) in 165 patients with non-small cell lung cancer (NSCLC) who received definitive chemoradiation therapy. Results were assessed by both Logistic and Cox regression models for RP risk. Kaplan-Meier curves were generated for the cumulative RP probability by the genotypes.

RESULTS

We found that SNPs of XRCC1 Q399R and APEX1 D148E each had a significant effect on the development of Grade ≥2 RP (XRCC1: AA vs. GG, adjusted hazard ratio [HR] = 0.48, 95% confidence interval [CI], 0.24-0.97; APEX1: GG vs. TT, adjusted HR = 3.61, 95% CI, 1.64-7.93) in an allele-dose response manner (Trend tests: p = 0.040 and 0.001, respectively). The number of the combined protective XRCC1 A and APEX1 T alleles (from 0 to 4) also showed a significant trend of predicting RP risk (p = 0.001).

CONCLUSIONS

SNPs of the base-excision repair genes may be biomarkers for susceptibility to RP. Larger prospective studies are needed to validate our findings.

Radiation pneumonitis in patients with lung and mediastinal tumours: a retrospective study of risk factors focused on pulmonary emphysema

OBJECTIVES

To evaluate the impact of pulmonary emphysema (PE) on the incidence and severity of radiation pneumonitis (RP) in patients with lung and mediastinal tumours.

METHODS

92 patients were enrolled. Involved-field radiation therapy (non-small cell carcinoma or mediastinal tumours in 69 patients; median 70 Gy) and accelerated hyperfractionation (limited disease small cell carcinoma in 23 patients; median 45 Gy) were performed. Common Terminology Criteria for Adverse Events v.3.0 was used to evaluate RP and the relationship with the percentage of pulmonary volume irradiated to >20 Gy (V20) and PE. PE was diagnosed by the presence of low-attenuation areas (LAAs) on CT scans and was classified into Grades 0-4 according to the extent of the LAAs.

RESULTS

The median follow-up time was 16 months. The 6-month cumulative incidence of RP at Grade 3 or greater was 7.7% and 34.1% in patients with a V20 of <25% and ≥25%, respectively (p=0.017). In patients with PE Grades 0, 1, 2 and 3 or greater, the incidence of RP was 16.5%, 9.1%, 8.6% and 54.0%, respectively. As the PE Grade increased, the incidence of RP also increased significantly.

CONCLUSION

The incidence and severity of RP are significantly higher in patients with a high V20 value as well as in those with severe PE.

Effectiveness of rosiglitazone on bleomycin-induced lung fibrosis: Assessed by micro-computed tomography and pathologic scores

Peroxisome proliferator-activated receptor-γ (PPARγ) agonists exhibit potent anti-fibrotic effects in the lung and other tissues. Recently, micro-computed tomography (CT) has been a useful tool for the investigation of lung diseases in small animals and is now increasingly applied to visualize and quantify the pulmonary structures. However, there is little information on the assessment for therapeutic effects of PPARγ agonists on the pulmonary fibrosis in mice using micro-CT. This study was aimed to determine the capability of micro-CT in examining the effects of rosiglitazone on pulmonary fibrosis. We used a murine model of bleomycin-induced lung fibrosis to evaluate the feasibility of micro-CT in evaluating the therapeutic potential of rosiglitazone on pulmonary fibrosis, comparing with pathologic scores. On micro-CT findings, ground glass opacity (80%) and consolidation (20%) were observed predominantly at 3 weeks after the instillation of bleomycin, and the radiologic features became more complex at 6 weeks. In bleomycin-instilled mice treated with rosiglitazone, the majority (80%) showed normal lung features on micro-CT. Radiological-pathologic correlation analyses revealed that ground glass opacity and consolidation were correlated closely with acute inflammation, while reticular opacity was well correlated with histological honeycomb appearance. These results demonstrate that rosiglitazone displays a protective effect on pulmonary fibrosis in mice and that the visualization of bleomycin-induced pulmonary fibrosis using micro-CT is satisfactory to assess the effects of rosiglitazone. It implies that micro-CT can be applied to evaluate therapeutic efficacies of a variety of candidate drugs for lung diseases.

Technological advances in radiotherapy for esophageal cancer

Radiotherapy with concurrent chemotherapy and surgery represent the main treatment modalities in esophageal cancer. The goal of modern radiotherapy approaches, based on recent technological advances, is to minimize post-treatment complications by improving the gross tumor volume definition (positron emission tomography-based planning), reducing interfraction motion (image-guided radiotherapy) and intrafraction motion (respiratory-gated radiotherapy), and by better dose delivery to the precisely defined planning target volume (intensity-modulated radiotherapy and proton therapy). Reduction of radiotherapy-related toxicity is fundamental to the improvement of clinical results in esophageal cancer, although the dose escalation concept is controversial.

Peculiaridades da radioterapia em idosos

É sabido que o envelhecimento da população do mundo durante o século XX e no início deste novo século constitui um desafio de primeira ordem para as nações, especialmente no campo socioeconômico. Um aspecto importante do envelhecimento populacional global é que, para grupos de idade mais avançada, a prevalência das doenças degenerativas também é maior, incluindo as doenças malignas. No universo de pacientes portadores de câncer, por outro lado, metade destes receberá radioterapia em algum momento de sua doença e suas características individuais podem influenciar, de alguma forma, o prognóstico, a indicação e as doses diárias de prescrição dos tratamentos. Neste contexto, a assistência à saúde do idoso portador de câncer deve ser vista como um importante desafio, principalmente devido a dois fatores: uma maior procura de tratamentos, em termos quantitativos, e características fisiológicas peculiares a esta população, que podem influenciar na tomada de decisões terapêuticas. Esta revisão propõe uma discussão sobre alguns aspectos relevantes tanto da fisiologia dos idosos, que pode influenciar o curso do tratamento irradiante, quanto de alguns avanços técnicos da radioterapia, que podem, por sua vez, beneficiar estes pacientes, oferecendo menor toxicidade e maior eficiência e rapidez, por exemplo.

Targeting the TGF-beta1 pathway to prevent normal tissue injury after cancer therapy

With >10,000,000 cancer survivors in the U.S. alone, the late effects of cancer treatment are a significant public health issue. Over the past 15 years, much work has been done that has led to an improvement in our understanding of the molecular mechanisms underlying the development of normal tissue injury after cancer therapy. In many cases, these injuries are characterized at the histologic level by loss of parenchymal cells, excessive fibrosis, and tissue atrophy. Among the many cytokines involved in this process, transforming growth factor (TGF)-beta1 is thought to play a pivotal role. TGF-beta1 has a multitude of functions, including both promoting the formation and inhibiting the breakdown of connective tissue. It also inhibits epithelial cell proliferation. TGF-beta1 is overexpressed at sites of injury after radiation and chemotherapy. Thus, TGF-beta1 represents a logical target for molecular therapies designed to prevent or reduce normal tissue injury after cancer therapy. Herein, the evidence supporting the critical role of TGF-beta1 in the development of normal tissue injury after cancer therapy is reviewed and the results of recent research aimed at preventing normal tissue injury by targeting the TGF-beta1 pathway are presented.