Toxicity of thoracic radiotherapy on pulmonary function in lung cancer

Changes in lung volume parameters regarding the received dose in the lobes of the lungs after locoregional radiotherapy of breast cancer

Aim

The purpose of this study was to evaluate ΔLVP and correlate them with MLD and V20 in the lobes of the lung.

Background

Radiation-induced lung injury after breast irradiation is controversial. The incidence of such an injury could have negative consequences on breast cancer patients.

Materials and Methods

Twenty-three women treated with Breast-conserving surgery, chemotherapy, and locoregional RT underwent body plethysmography pre-RT and 3 and 6 months post-RT. Statistical analysis was used to evaluate ΔLVP over time and relate them with MLD, V20, age, and concurrent hormonal therapy.

Results

LVP decreased after 3 months and then showed a slight improvement by returning partially to their pre-RT values after 6 months. The mean ΔLVP was -0.64% for one Gy increase of MLD and -0.34% for one percent increase of V20 after 3 months. After 6 months, only ΔVC showed 0.45% reduction with MLD in the upper lobe. Finally, there was no significant correlation between ΔLVP with respect to age and concurrent hormonal therapy.

Conclusions

The results of this study showed that lung volume changes were not a cause for concern in breast cancer patients. There are three reasons to support this conclusion. Lung volume changes and percentage reductions in LVP for each Gy increase of MLD and each percentage increase of V20 in each lobe were small; patients were asymptomatic during the follow-up period; and LVP showed partial improvements after 6 months.

Quantification of regional early stage gas exchange changes using hyperpolarized (129)Xe MRI in a rat model of radiation-induced lung injury

PURPOSE

To assess the feasibility of hyperpolarized (HP) (129)Xe MRI for detection of early stage radiation-induced lung injury (RILI) in a rat model involving unilateral irradiation by assessing differences in gas exchange dynamics between irradiated and unirradiated lungs.

METHODS

The dynamics of gas exchange between alveolar air space and pulmonary tissue (PT), PT and red blood cells (RBCs) was measured using single-shot spiral iterative decomposition of water and fat with echo asymmetry and least-squares estimation images of the right and left lungs of two age-matched cohorts of Sprague Dawley rats. The first cohort (n = 5) received 18 Gy irradiation to the right lung using a (60)Co source and the second cohort (n = 5) was not irradiated and served as the healthy control. Both groups were imaged two weeks following irradiation when radiation pneumonitis (RP) was expected to be present. The gas exchange data were fit to a theoretical gas exchange model to extract measurements of pulmonary tissue thickness (LPT) and relative blood volume (VRBC) from each of the right and left lungs of both cohorts. Following imaging, lung specimens were retrieved and percent tissue area (PTA) was assessed histologically to confirm RP and correlate with MRI measurements.

RESULTS

Statistically significant differences in LPT and VRBC were observed between the irradiated and non-irradiated cohorts. In particular, LPT of the right and left lungs was increased approximately 8.2% and 5.0% respectively in the irradiated cohort. Additionally, VRBC of the right and left lungs was decreased approximately 36.1% and 11.7% respectively for the irradiated cohort compared to the non-irradiated cohort. PTA measurements in both right and left lungs were increased in the irradiated group compared to the non-irradiated cohort for both the left (P < 0.05) and right lungs (P < 0.01) confirming the presence of RP. PTA measurements also correlated with the MRI measurements for both the non-irradiated (r = 0.79, P < 0.01) and irradiated groups (r = 0.91, P < 0.01).

CONCLUSIONS

Regional RILI can be detected two weeks post-irradiation using HP (129)Xe MRI and analysis of gas exchange curves. This approach correlates well with histology and can potentially be used clinically to assess radiation pneumonitis associated with early RILI to improve radiation therapy outcomes.

Changes in pulmonary function and influencing factors after high-dose intrathoracic radio(chemo)therapy

PURPOSE

Using prospectively collected patient-related, dose-related, and pulmonary function test (PFT) data before radiotherapy (RT) and at several follow-up visits after RT, the time course of PFT changes after high-dose radio(chemo)therapy and influencing factors were analyzed.

MATERIALS AND METHODS

From April 2012 to October 2015, 81 patients with non-small-cell lung carcinoma (NSCLC), small cell lung carcinoma (SCLC), or esophageal carcinoma where treated with high-dose radio(chemo)therapy. PFT data were collected before treatment and 6 weeks, 12 weeks, and 6 months after RT. The influence of patient- and treatment-related factors on PFT was analyzed.

RESULTS

Mean forced expiratory volume in 1 s (FEV1) constantly declined during follow-up (p = 0.001). In total, 68% of patients had a reduced FEV1 at 6 months. Mean vital capacity (VC) didn't change during follow-up (p > 0.05). Mean total lung capacity (TLC) showed a constant decline after RT (p = 0.026). At 6 months, 60% of patients showed a decline in VC and 73% in TLC. The mean diffusion capacity for carbon monoxide (DLCO) declined at 6 and 12 weeks, but recovered slightly at 6 months (p < 0.0005). At 6 months, 86% of patients had a reduced DLCO. After treatment, the partial pressure of CO₂ in the blood (pCO₂) was increased and pO₂ was decreased (p > 0.05). Only the pretreatment PFT classification had a significant influence on the post-RT FEV1.

CONCLUSION

DLCO seems to be the most reliable indicator for lung tissue damage after thoracic RT. Ventilation parameters appear to be less reliable. Concerning patient- or treatment-related factors, no reliable conclusion can be drawn regarding which factors may be relevant.

Suggestion for a new grading scale for radiation induced pneumonitis based on radiological findings of computerized tomography: correlation with clinical and radiotherapeutic parameters in lung cancer patients

BACKGROUND

The objective of this research is the computed axial tomography (CT) imaging grading of radiation induced pneumonitis (RP) and its correlation with clinical and radiotherapeutic parameters.

MATERIALS AND METHODS

The chest CT films of 20 patients with non-small cell lung cancer who have undergone three- dimensional conformal radiation therapy were reviewed. The proposed CT grading of RP is supported on solely radiological diagnosis criteria and distinguishes five grades. The manifestation of RP was also correlated with any positive pre-existing chronic obstructive pulmonary disease (COPD) history, smoking history, the FEV1 value, and the dosimetric variable V20.

RESULTS

The CT grading of RP was as follows: 3 patients (15%) presented with ground glass opacity (grade 1), 9 patients (45%) were classified as grade 2, 7 patients (35%) presented with focal consolidation, with or without elements of fibrosis (grade 3), and only one patient (5%) presented with opacity with accompanying atelectasis and loss of pulmonary volume (grade 4). Both univariate and multivariate analysis revealed as prognostic factors for the radiological grading of RP the reduction of FEV1 and the V20 (P=0.026 and P=0.003, respectively). There was also a significant (P<0.001) correlation of radiological grading of RP with FEV1 and V20 (spearman rho 0.92 and 0.93, respectively).

CONCLUSIONS

The high correlation of the proposed radiological grading with the FEV1 and the V20 is giving a satisfactory clinical validity. Although the proposed grading scale seems relevant to clinical practice, further studies are needed for the confirmation of its validity and reliability.

Nondosimetric risk factors for radiation-induced lung toxicity

The decision to administer a radical course of radiotherapy (RT) is largely influenced by the dose-volume metrics of the treatment plan, but what are the patient-related and other factors that may independently increase the risk of radiation lung toxicity? Poor pulmonary function has been regarded as a risk factor and a relative contraindication for patients undergoing radical RT, but recent evidence suggests that patients with poor spirometry results may tolerate conventional or high-dose RT as well as, if not better than, patients with normal function. However, caution may need to be exercised in patients with underlying interstitial pulmonary fibrosis. Furthermore, there is emerging evidence of molecular markers of increased risk of toxicity. This review discusses patient-related risk factors other than dosimetry for radiation lung toxicity.

Lung

The lungs are particularly sensitive to RT, and are often the primary dose-limiting structure during thoracic therapy.

The alveolar/capillary units and pneumocytes within the alveoli appear to be particularly sensitive to RT.

Hypoxia may be important in the underlying physiology of RT-associated lung injury.

The cytokine transforming growth factor-beta (TGF-β), plays an important role in the development of RT-induced fibrosis.

The histopathological changes observed in the lung after RT are broadly characterized as diffuse alveolar damage.

The interaction between pre-treatment PFTs and the risk of symptomatic lung injury is complex. Similarly, the link between changes in PFTs and the development of symptoms is uncertain.

The incidence of symptomatic lung injury increases with increase in most dosimetric parameters. The mean lung dose (MLD) and V20 have been the most-often considered parameters. MLD might be a preferable metric since it considers the entire 3D dose distribution.

Radiation to the lower lobes appears to be more often associated with clinical symptoms than is radiation to the upper lobes. This might be related to incidental cardiac irradiation. In pre-clinical models, there appears to be a complex interaction between lung and heart irradiation.

TGF-β has been suggested in several studies to predict for RT-induced lung injury, but the data are still somewhat inconsistent.

Oral prednisone (Salinas and Winterbauer 1995), typically 40–60 mg daily for 1–2 weeks with a slow taper, is usually effective in treating pneumonitis. There are no widely accepted treatments for fibrosis.

A number of chemotherapeutic agents have been suggested to be associated with a range of pulmonary toxicities.

Computed tomography fluoroscopy-guided percutaneous 125I seed implantation for safe, effective and real-time monitoring radiotherapy of inoperable stage T1-3N0M0 non-small-cell lung cancer

The management of inoperable lung cancer remains a challenge. It has been proven that computed tomography (CT)-guided iodine-125 (¹²⁵I) seed implantation is a safe and efficient method for treating lung cancer. Computed tomographic fluoroscopy (CTF) is superior to traditional CT for percutaneous management of lung lesions, due to the real-time guidance and accurate localization of the lesions. The aim of the present prospective study was to evaluate the feasibility, safety and efficacy of CTF-guided percutaneous permanent implantation of ¹²⁵I seeds for the treatment of selected patients with inoperable stage T1-3N0M0 non-small-cell lung cancer (NSCLC). A total of 24 patients with resectable but inoperable stage T1-3N0 NSCLC, with a total of 28 lesions, underwent CTF-guided percutaneous implantation of radioactive ¹²⁵I seeds. A prescription dose of 100-120 Gy was delivered to each lesion. The complications and local tumor control rates were documented. Survival was estimated using the Kaplan-Meier method. All the patients successfully completed the procedure, with a mean procedure duration of 45.7 min (range, 30-75 min). No severe complications occurred. Small asymptomatic pneumothorax with lung volume compression of <10% and minor hemorrhage along the needle track without hemoptysis occurred immediately after the procedure in 3 (12.5%) and 4 (16.7%) of the 24 patients, respectively. At a median follow-up of 31.5 months (range, 8-46 months), the local control rate (LCR) of the lesions was 78.6% (22/28). The 1-, 2- and 3-year overall survival rate was 95.8, 78 and 55%, respectively. In conclusion, CTF is the favourable imaging guidance method for the percutaneous implantation of ¹²⁵I seeds. CTF-guided brachytherapy with implantation of ¹²⁵I seeds is a safe, feasible and effective modality for the treatment of inoperable early-stage NSCLC and may be considered an alternative option in selected patients with medically inoperable NSCLC.

Role of particle beam therapy in a trimodality approach to locally advanced non-small cell lung cancer

Lung cancer accounts for nearly one-fifth of all cancer deaths worldwide and is the most common cause of cancer-related death in the United States. Outcomes for locally advanced non-small cell lung cancer remain extremely poor with regards to both local control and overall survival. Modest gains in local control were obtained with the incorporation of multimodality treatment, including preoperative chemotherapy followed by surgical resection; combination chemoradiotherapy also improved survival, secondary to improved local control. While the natural progression to trimodality therapy resulted in superior local control, it did not translate to improved overall survival, secondary to increased toxicity. The additional morbidity is likely from radiation toxicity, the minimization of which will be crucial to the future success of trimodality therapy. One strategy to decrease toxicity is to utilize charged particles, such as protons, which deposit a high dose at the Bragg peak with a minimal dose beyond the peak, thereby reducing the dose to distal normal tissues. Trimodality therapy incorporating preoperative proton radiation therapy and chemotherapy, followed by surgery, is currently being evaluated as a potential strategy to achieve improved local control and overall survival in locally advanced non-small cell lung cancer.

Poor baseline pulmonary function may not increase the risk of radiation-induced lung toxicity

PURPOSE

Poor pulmonary function (PF) is often considered a contraindication to definitive radiation therapy for lung cancer. This study investigated whether baseline PF was associated with radiation-induced lung toxicity (RILT) in patients with non-small cell lung cancer (NSCLC) receiving conformal radiation therapy (CRT).

METHODS AND MATERIALS

NSCLC patients treated with CRT and tested for PF at baseline were eligible. Baseline predicted values of forced expiratory volume in 1 sec (FEV1), forced vital capacity (FVC), and diffusion capacity of lung for carbon monoxide (DLCO) were analyzed. Additional factors included age, gender, smoking status, Karnofsky performance status, coexisting chronic obstructive pulmonary disease (COPD), tumor location, histology, concurrent chemotherapy, radiation dose, and mean lung dose (MLD) were evaluated for RILT. The primary endpoint was symptomatic RILT (SRILT), including grade ≥2 radiation pneumonitis and fibrosis.

RESULTS

There was a total of 260 patients, and SRILT occurred in 58 (22.3%) of them. Mean FEV1 values for SRILT and non-SRILT patients were 71.7% and 65.9% (P=.077). Under univariate analysis, risk of SRILT increased with MLD (P=.008), the absence of COPD (P=.047), and FEV1 (P=.077). Age (65 split) and MLD were significantly associated with SRILT in multivariate analysis. The addition of FEV1 and age with the MLD-based model slightly improved the predictability of SRILT (area under curve from 0.63-0.70, P=.088).

CONCLUSIONS

Poor baseline PF does not increase the risk of SRILT, and combining FEV1, age, and MLD may improve the predictive ability.

Lung Cancer Survival With Herbal Medicine and Vitamins in a Whole-Systems Approach

Complementary and alternative medicines are used by up to 48% of lung cancer patients but have seen little formal assessment of survival efficacy. In this 10-year retrospective survival study, the authors investigated Pan-Asian medicine + vitamins (PAM+V) therapy in a consecutive case series of all non-small-cell lung cancer patients (n = 239) presenting at a San Francisco Bay Area Chinese medicine center (Pine Street Clinic). They compared short-term treatment lasting the duration of chemotherapy/radiotherapy with long-term therapy continuing beyond conventional therapy. They also compared PAM+V plus conventional therapy with conventional therapy alone, using concurrent controls from the Kaiser Permanente Northern California and California Cancer Registries. They adjusted for confounding with Kaplan-Meier, Cox regression, and newer methods – propensity score and marginal structural models (MSMs), which when analyzing data from observational studies or clinical practice records can provide results comparable with randomized trials. Long-term use of PAM+V beyond completion of chemotherapy reduced stage IIIB deaths by 83% and stage IV by 72% compared with short-term use only for the duration of chemotherapy. Long-term PAM+V combined with conventional therapy reduced stage IIIA deaths by 46%, stage IIIB by 62%, and stage IV by 69% compared with conventional therapy alone. Survival rates for stage IV patients treated with PAM+V were 82% at 1 year, 68% at 2 years, and 14% at 5 years. PAM+V combined with conventional therapy improved survival in stages IIIA, IIIB, and IV, compared with conventional therapy alone. Prospective trials using PAM+V with conventional therapy for lung cancer patients are justified.

Combined radiofrequency ablation and high-dose rate brachytherapy for early-stage non-small-cell lung cancer

PURPOSE

This retrospective analysis reports the results of patients with early-stage inoperable non-small-cell lung cancer treated with radiofrequency ablation (RFA) followed by adjuvant high-dose rate (HDR) brachytherapy.

METHODS AND MATERIALS

Seventeen medically inoperable patients with biopsy-proven Stage I non-small-cell lung cancer were treated with RFA followed by single fraction HDR brachytherapy. Brachytherapy catheters were inserted immediately after RFA, and one fraction of HDR brachytherapy was delivered on the same day. Doses of brachytherapy ranged from 14.4 to 20 Gy (median, 18 Gy). Patients were followed clinically and radiographically to determine tumor control and toxicity profile.

RESULTS

Median followup time was 22 months. Of the 17 patients, 3 patients have recurred locally. Each of the patients with local recurrences was originally treated for T2 disease. In total, three of seven cases with T2N0 disease experienced local recurrences, whereas all 9 patients with T1 disease were controlled locally. Five of the 17 patients required a chest tube posttreatment, and 1 patient developed an empyema. There were no deaths within 1 month of treatment.

CONCLUSIONS

RFA followed by HDR brachytherapy yields excellent local control with an acceptable toxicity profile for patients with otherwise inoperable early-stage lung cancer.

Detection of radiation-induced lung injury in non-small cell lung cancer patients using hyperpolarized helium-3 magnetic resonance imaging

PURPOSE

To compare hyperpolarized helium-3 magnetic resonance imaging ((3)He-MRI) acquired from non-small cell lung cancer (NSCLC) patients before and after external beam radiotherapy (EBRT).

METHODS AND MATERIALS

In an Ethics Committee-approved prospective study, five patients with histologically confirmed NSCLC gave written informed consent to undergo computed tomography (CT) and (3)He-MR ventilation imaging 1 week prior to and 3 months after radiotherapy. Images were registered to pre-treatment CT using anatomical landmark-based rigid registration to enable comparison. Emphysema was graded from examination of the CT. MRI-defined ventilation was calculated as the intersection of (3)He-MRI and CT lung volume as a percentage of the CT lung volume for the whole lung and regions of CT-defined pneumonitis.

RESULTS

On pre-treatment images, there was a significant correlation between the degree of CT-defined emphysema and (3)He-MRI whole lung ventilation (Spearman's rho=0.90, p=0.04). After radiation therapy, pneumonitis was evident on CT for 3/5 patients. For these cases, (3)He-MRI ventilation was significantly reduced within the regions of pneumonitis (pre: 94.1±2.2%, post: 73.7±4.7%; matched pairs Student's t-test, p=0.02, mean difference=20.4%, 95% confidence interval 6.3-34.6%).

CONCLUSIONS

This work demonstrates the feasibility of detecting ventilation changes between pre- and post-treatment using hyperpolarized helium-3 MRI for patients with NSCLC. Pre-treatment, the degree of emphysema and (3)He-MRI ventilation were correlated. For three cases of radiation pneumonitis, (3)He-MRI ventilation changes between pre- and post-treatment imaging were consistent with CT evidence of radiation-induced lung injury.

Follow-up and surveillance of the lung cancer patient following curative intent therapy: ACCP evidence-based clinical practice guideline (2nd edition)

BACKGROUND

To develop an evidence-based approach to follow-up of patients after curative intent therapy for lung cancer.

METHODS

Guidelines on lung cancer diagnosis and management published between 2002 and December 2005 were identified by a systematic review of the literature, and supplemental material appropriate to this topic was obtained by literature search of a computerized database (Medline) and review of the reference lists of relevant articles.

RESULTS

Adequate follow-up by the specialist responsible for the curative intent therapy should be ensured to manage complications related to the curative intent therapy and should last at least 3 to 6 months. In addition, a surveillance program should be considered to detect recurrences of the primary lung cancer and/or development of a new primary lung cancer early enough to allow potentially curative retreatment. A standard surveillance program for these patients, coordinated by a multidisciplinary tumor board and overseen by the physician who diagnosed and initiated therapy for the original lung cancer, is recommended based on periodic visits with chest imaging studies and counseling patients on symptom recognition. Smoking cessation and, if indicated, facilitation in participation in special programs is recommended for all patients following curative intent therapy for lung cancer.

CONCLUSIONS

The current evidence favors follow-up of complications related to curative intent therapy, and a surveillance program at regular intervals with imaging and review of symptoms. Smoking cessation after curative intent therapy to prevent recurrence of lung cancer is strongly supported by the available evidence.

Updated assessment of the six-minute walk test as predictor of acute radiation-induced pneumonitis

PURPOSE

To assess the utility of the 6-minute walk test (6MWT) as a predictor of symptomatic radiation-induced pneumonitis (RP).

METHODS

As part of a prospective trial to study radiation-induced lung injury, 53 patients receiving thoracic radiotherapy (RT) underwent a pre-RT 6MWT, pulmonary function tests (PFTs), and had >or=3-month follow-up for prospective assessment of Grade 2 or worse RP (requiring medications or worse). Dosimetric parameters (e.g., the percentage of lung receiving >or=30 Gy) were extracted from the lung dose-volume histogram. The correlations between the 6MWT and PFT results were assessed using Pearson's correlation. The receiver operating characteristic technique was used in patient subgroups to evaluate the predictive capacities for RP of the dosimetric parameters, 6MWT results, and PFT results, or the combination (using discriminant analysis) of all three metrics. ROCKIT software was used to compare the receiver operating characteristic areas between each predictive model. The association of the decline in 6MWT with the development of RP was evaluated using Fisher's exact test.

RESULTS

The pre-RT PFT and 6MWT results correlated weakly (r = 0.44-0.57, p <or= 0.001), suggesting that they measure somewhat different physiologic functions. Of the 53 patients, 9 (17%) developed RP. The dose-volume histogram-based dosimetric parameters were the best single-metric model for predicting RP (e.g., percentage of lung receiving >or=30 Gy, receiver operating characteristic area 0.73, p = 0.03). Including the PFT or 6MWT results with the percentage of lung receiving >or=30 Gy did not improve the predictions. The predictive abilities of dosimetric-based models improved when the analysis was restricted to those patients whose tumors were not causing regional lung dysfunction. No correlation was found between the decline in the 6MWT result and the RP rate (p = 0.6).

CONCLUSION

Although the PFTs and 6MWT are related to each other, the correlation coefficients were weak, suggesting that they could be measuring different physiologic functions. In the present data set, the addition of the PFTs or 6MWT did not increase the ability of the dosimetric parameters to predict for acute symptomatic RP. Additional work is needed to better understand the interaction among the PFT results, exercise tolerance (6MWT), and the risk of RT-induced lung dysfunction.

The impact of induction chemotherapy and the associated tumor response on subsequent radiation-related changes in lung function and tumor response

PURPOSE

To assess the impact of induction chemotherapy, and associated tumor shrinkage, on the subsequent radiation-related changes in pulmonary function and tumor response.

METHODS AND MATERIALS

As part of a prospective institutional review board-approved study, 91 evaluable patients treated definitively with thoracic radiation therapy (RT) for unresectable lung cancer were analyzed. The rates of RT-associated pulmonary toxicity and tumor response were compared in the patients with and without pre-RT chemotherapy. In the patients receiving induction chemotherapy, the rates of RT-associated pulmonary toxicity and tumor response were compared in the patients with and without a response (modified Response Evaluation Criteria in Solid Tumor criteria) to the pre-RT chemotherapy. Comparisons of the rates of improvements in pulmonary function tests (PFTs) post-RT, dyspnea requiring steroids, and percent declines in PFTs post-RT were compared in patient subgroups using Fisher's exact test, analysis of variance, and linear or logistic regression.

RESULTS

The use of pre-RT chemotherapy appears to increase the rate of radiation-induced pneumonitis (p = 0.009-0.07), but has no consistent impact on changes in PFTs. The degree of induction chemotherapy-associated tumor shrinkage is not associated with the rate of subsequent RT-associated pulmonary toxicity. The degree of tumor response to chemotherapy is not related to the degree of tumor response to RT.

CONCLUSIONS

Additional study is needed to better clarify the impact of chemotherapy on radiation-associated disfunction.

The pulmonary status of patients with limited-stage small cell lung cancer 15 years after treatment with chemotherapy and chest irradiation

STUDY OBJECTIVES

To describe pulmonary symptoms, signs, pulmonary function, and lung imaging studies in patients with limited-stage small cell lung cancer (SCLC) 2 to 15 years after receiving treatment with chemotherapy and chest radiotherapy.

DESIGN

Retrospective review of clinical records and radiographic studies of patients treated in three different prospective combined-modality studies.

SETTING

Federal hospital.

PATIENTS

One hundred fifty-six patients with SCLC who were enrolled between 1974 and 1994.

INTERVENTIONS

Patients with limited-stage SCLC treated on prospective therapeutic studies of combined chemotherapy and radiation therapy were identified. Pulmonary symptoms, physical findings, pulmonary function tests, arterial blood gas measurements, and chest imaging studies were assessed at baseline, and at 1 to 2 years, at 3 to 5 years, and at > 5 years following the initiation of treatment.

MEASUREMENTS AND RESULTS

Initial symptoms included cough in 84 (55%), dyspnea in 59 (39%), and sputum production in 26 (17%). Twenty-three patients lived beyond 5 years (15%) without evidence of recurrence. Seven of these 5-year survivors were without pulmonary symptoms. Pulmonary function test results showed no significant changes in percent predicted values for FVC, FEV(1), and FEV(1)/FVC ratio over the time periods reviewed. The percent predicted values for the diffusing capacity of the lung for carbon monoxide decreased from 71% before the start of treatment to 56% (p < 0.032) at 1 to 2 years. Values improved in most patients beyond 5 years after starting treatment. Radiologist interpretations of chest imaging studies were available for 17 of 23 patients surviving > 5 years. Most patients had minimal to no changes in imaging study findings beyond 5 years.

CONCLUSIONS

Long-term survivors with limited-stage SCLC who were treated with combined chemotherapy and chest radiotherapy have minimal changes in pulmonary symptoms or function from 5 to 15 years after the start of treatment. A concern for late toxicity from combined-modality therapy should not dissuade clinicians from offering therapy with potentially curative result with minimal to no pulmonary dysfunction.

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

Although radiotherapy improves locoregional control and survival in patients with non-small-cell lung cancer, radiation pneumonitis is a common treatment-related toxicity. Many pulmonary function tests are not significantly altered by pulmonary toxicity of irradiation, but reductions in D(L(CO)), the diffusing capacity of carbon monoxide, are more commonly associated with pneumonitis. Several patient-specific factors (e.g. age, smoking history, tumor location, performance score, gender) and treatment-specific factors (e.g. chemotherapy regimen and dose) have been proposed as potential predictors of the risk of radiation pneumonitis, but these have not been consistently demonstrated across different studies. The risk of radiation pneumonitis also seems to increase as the cumulative dose of radiation to normal lung tissue increases, as measured by dose-volume histograms. However, controversy persists about which dosimetric parameter optimally predicts the risk of radiation pneumonitis, and whether the volume of lung or the dose of radiation is more important. Radiation oncologists ought to consider these dosimetric factors when designing radiation treatment plans for all patients who receive thoracic radiotherapy. Newer radiotherapy techniques and technologies may reduce the exposure of normal lung to irradiation. Several medications have also been evaluated for their ability to reduce radiation pneumonitis in animals and humans, including corticosteroids, amifostine, ACE inhibitors or angiotensin II type 1 receptor blockers, pentoxifylline, melatonin, carvedilol, and manganese superoxide dismutase-plasmid/liposome. Additional research is warranted to determine the efficacy of these medications and identify nonpharmacologic strategies to predict and prevent radiation pneumonitis.

Pulmonary function changes after radiotherapy in non-small-cell lung cancer patients with long-term disease-free survival

PURPOSE

To evaluate the changes in pulmonary function after high-dose radiotherapy (RT) for non-small-cell lung cancer in patients with a long-term disease-free survival.

METHODS AND MATERIALS

Pulmonary function was measured in 34 patients with inoperable non-small-cell lung cancer before RT and at 3 and 18 months of follow-up. Thirteen of these patients had a pulmonary function test (PFT) 36 months after RT. The pulmonary function parameters (forced expiratory volume in 1 s [FEV(1)], diffusion capacity [T(lcoc)], forced vital capacity, and alveolar volume) were expressed as a percentage of normal values. Changes were expressed as relative to the pre-RT value. We evaluated the impact of chronic obstructive pulmonary disease, radiation pneumonitis, mean lung dose, and PFT results before RT on the changes in pulmonary function.

RESULTS

At 3, 18, and 36 months, a significant decrease was observed for the T(lcoc) (9.5%, 14.6%, and 22.0%, respectively) and the alveolar volume (5.8%, 6.6%, and 15.8%, respectively). The decrease in FEV(1) was significant at 18 and 36 months (8.8% and 13.4%, respectively). No recovery of any of the parameters was observed. Chronic obstructive pulmonary disease was an important risk factor for larger PFT decreases. FEV(1) and T(lcoc) decreases were dependent on the mean lung dose.

CONCLUSION

A significant decrease in pulmonary function was observed 3 months after RT. No recovery in pulmonary function was seen at 18 and 36 months after RT. The decrease in pulmonary function was dependent on the mean lung dose, and patients with chronic obstructive pulmonary disease had larger reductions in the PFTs.

Interstitial lung disease in lung cancer: separating disease progression from treatment effects

Lung cancer often develops in individuals with pre-existing pulmonary and cardiac pathology. Many of these individuals with pre-existing pathology are also at risk of occupational lung disease. New and worsening symptoms can be secondary to pre-existing pathology, progressive cancer or treatment. Pulmonary toxicity, including interstitial lung disease, following radiotherapy and conventional cytotoxic chemotherapy (e.g. cyclophosphamide, bleomycin), has been recognised for many years. Pulmonary toxicity also occurs with the newer classes of cytotoxic agents, including the deoxycytidine analogue gemcitabine. A small percentage (0.88%) of patients treated with the epidermal growth factor receptor tyrosine kinase inhibitor gefitinib have developed interstitial lung disease. This complication has been reported at a higher frequency in Japanese patients than in US patients (1.9% vs 0.34%, respectively) and in those with pre-existing pulmonary fibrosis. This review discusses the difficulties in both recognition and treatment of gefitinib-associated interstitial lung disease. Symptoms are vague, such as dyspnoea, cough and fever and can be difficult to differentiate from progressive disease, co-existing morbidity and new pulmonary pathology. Diagnosis is, therefore, by rigorous investigation to exclude all other differential diagnoses. Treatment, at present, is supportive and includes discontinuation of gefitinib, oxygen supplementation, high-dose corticosteroids and antibacterials.

Long-term changes in pulmonary function tests after definitive radiotherapy for lung cancer

PURPOSE

To evaluate the long-term changes in pulmonary function tests (PFTs) in patients surviving at least 2 years after definitive radiotherapy (RT) for unresectable lung cancer.

METHODS AND MATERIALS

Between 1992 and 2000, 277 patients were enrolled in a prospective clinical study to relate RT-induced changes in lung function with dosimetric and functional metrics. Of these, 128 received definitive RT for lung cancer, and 13 of these had follow-up PFTs for approximately >/=2 years without evidence of recurrent or progressive cancer. PFTs were obtained before RT and approximately every 6 months after RT. The results were evaluated on the basis of each study's "percentage of predicted" of normal values (i.e., adjusted for age, gender, height), and a patient's sequential examinations were compared with their initial study and a percentage of the baseline value was calculated. Follow-up PFTs were available for a median of 38 months (range 23-95). The median patient age was 65 years (range 40-74), 6 patients were men, and 10 were white. Most had Stage T2-T4 and N2-N3. The median RT dose was 71.4 Gy (range 60-73), 6 had twice-daily RT. Four patients received chemotherapy, one concurrent and three neoadjuvant. None of the patients continued to smoke after their treatment. The median pre-RT PFT results were (percentage of predicted) forced expiratory volume in 1 s, 67% (range 24-121); forced vital capacity, 72% (range 45-116); and diffusing capacity of lung for carbon monoxide, 70% (range 41-129).

RESULTS

At 6 months, all PFT values had declined, with some stabilization by 1 year. However, after 1 year, a gradual reduction occurred in all three parameters. Ten patients (77%) developed RT-induced respiratory symptoms (2 cough only, 8 dyspnea) at 2-21 months (median 5) after treatment. Two patients required inhalers, another required long-term steroids and oxygen. Of the 8 patients with dyspnea, 7 had an increase in symptoms beyond 2 years. No patient died of RT-induced pulmonary insufficiency.

CONCLUSION

RT caused a decline in PFTs that was apparent at 6 months and continued well beyond 1 year. The continued decline in PFTs is suggestive of progressive/evolving RT-induced lung injury. "Late" pulmonary symptoms have also occurred in these patients. Because of the high mortality rate of unresectable lung cancer, few patients can be evaluated for long-term analysis. Additional studies and pooling of data from multiple institutions may help to clarify better the long-term impact of RT on pulmonary function in this subset of patients.

Lung cancer 5: state of the art radiotherapy for lung cancer

Radiotherapy has a key role in curative and palliative treatments of patients with lung cancer. Important advances are described in the technique of treatment delivery and its integration with chemotherapy.

Pulmonary function following high-dose radiotherapy of non-small-cell lung cancer

PURPOSE

To study changes of pulmonary function tests (PFTs) after radiotherapy (RT) of non-small-cell lung cancer (NSCLC) in relation to radiation dose, tumor regression, and changes in lung perfusion.

METHODS AND MATERIALS

Eighty-two patients with inoperable NSCLC were evaluated with PFTs (forced expiratory volume in 1 s [FEV(1)] and diffusion capacity [T(L,COc)]), a computed tomography (CT) scan of the chest, and a single photon emission CT (SPECT) lung perfusion scan, before and 3-4 months after RT. The reductions of PFTs and tumor volume were calculated. The lung perfusion was measured from pre- and post-RT SPECT scans, and the difference was defined as the measured perfusion reduction (MPR). In addition, the perfusion post-RT was estimated from the dose distribution using a dose-effect relation for regional lung perfusion, and compared with the pre-RT lung perfusion to obtain the predicted perfusion reduction (PPR). The difference between the actually measured and the PPR was defined as reperfusion. The mean lung dose (MLD) was computed and weighted with the pre-RT perfusion, resulting in the mean perfusion-weighted lung dose (MpLD). Changes of PFTs were evaluated in relation to tumor dose, MLD, MpLD, tumor regression, and parameters related to perfusion changes.

RESULTS

In a multivariate analysis, the total tumor dose and MLD were not associated with reductions of PFTs. Tumor regression resulted in a significant improvement of FEV(1) (p = 0.02), but was associated with a reduction of T(L,COc) (p = 0.05). The MpLD and the PPR showed a significant (p = 0.01 to 0.04) but low correlation (r = 0.24 to 0.31) with the reduction of both PFTs. The other parameters for perfusion changes, the MPR and reperfusion were not correlated with changes in PFTs.

CONCLUSION

The perfusion-related dose variables, the MpLD or the PPR, are the best parameters to estimate PFTs after RT. Tumor regression is associated with an improvement of FEV(1) and a decline of T(L,COc). Reperfusion was not associated with an improvement of global pulmonary function.

Lung cancer in elderly patients

Lung cancer is one of the most common causes of death in elderly patients in the United States. Treatment advances have improved survival in selected patients. The available treatments carry the risk of morbidity and mortality but the benefit in most patients far outweighs the risks, given the dismal prognosis of untreated disease. Elderly patients with lung cancer need careful attention during pretreatment assessment. Advanced age alone, however, should not contraindicate aggressive treatment. In the high-risk groups it is important to involve a team of physicians including surgeons, radiation oncologists, medical oncologists, and pulmonologists, who are familiar with current treatment options and their risks.

Follow-up and surveillance of the lung cancer patient following curative-intent therapy

The following two distinctly different issues should be taken into account when planning patient care following curative-intent therapy for lung cancer: adequate follow-up to manage complications related to the curative-intent therapy; and surveillance to detect recurrences of the primary lung cancer and/or development of a new primary lung cancer early enough to allow potentially curative retreatment. Follow-up for complications should be performed by the specialist responsible for the curative-intent therapy and should last 3 to 6 months. Recurrences of the original lung cancer will be more likely during the first 2 years after curative-intent therapy, but there will be an increased lifelong risk of approximately 1 to 2% per year of developing a metachronous, or new primary, lung cancer. A standard surveillance program for these patients is recommended based on periodic visits, with chest-imaging studies and counseling patients on symptom recognition. Whether subgroups of patients with a higher risk of developing a metachronous lung cancer (eg, those patients whose primary lung cancer was radiographically occult or central and those patients surviving for > 2 years after treatment for small cell lung cancer) should have a more intensive surveillance program is presently unclear. The surveillance program should be coordinated by a multidisciplinary tumor board and overseen by the physician who diagnosed and initiated therapy for the original lung cancer. Smoking cessation is recommended for all patients following curative-intent therapy for lung cancer.

Use of Postoperative Radiotherapy for Node-Positive non—small-Cell Lung Cancer

The appropriate patient selection for adjuvant radiotherapy after primary surgical therapy of non-small-cell lung cancer (NSCLC) is unclear. Four thousand thirteen patients diagnosed from 1988-1995 in 9 registry areas of the Survival, Epidemiology, and End Results program who received primary surgical therapy for pathologic stage T1-3 N1/2 M0 NSCLC were identified. County-level and patient-specific variables associated with the use of postoperative radiotherapy (PORT) were studied by multivariate logistic regression analysis. Prognostic factors for cause-specific survival (CSS) and overall survival (OS) were determined by Cox multivariate analysis. Overall, 58% of node-positive patients received PORT. Use of PORT was independently associated with younger age, more advanced nodal disease, no prior cancer, less extensive surgery than pneumonectomy, and patient residence close to a radiotherapy facility. In multivariate analysis of the entire node-positive population, there were no differences in OS or CSS with the use of PORT. In the patients with N2 disease, PORT was associated with improved OS (5-year OS: 16% without PORT, 22% with PORT; P = 0.001) and CSS (5-year CSS: 25% without PORT, 30% with PORT; P = 0.02). Additionally, patients with = 4 nodes involved also had an improved survival in association with PORT (5-year OS: 11% without PORT, 18% with PORT; P = 0.001; 5-year CSS: 17% without PORT, 25% with PORT; P = 0.009). Therefore, recognizing the inherent limitations of a retrospective, registry-based analysis, patients with more advanced nodal disease appear to have an improved survival with the use of PORT.

Effects of proton and combined proton/photon beam radiation on pulmonary function in patients with resectable but medically inoperable non-small cell lung cancer

STUDY OBJECTIVES

We evaluated the effects on pulmonary function of irradiating lung cancer with protons alone or protons combined with photons.

DESIGN

Prospective phase I/II study.

SETTING

University medical center.

PATIENTS AND INTERVENTIONS

Ten patients with stage I-II non-small cell lung cancer (NSCLC) and FEV(1) < or = 1.0 L were irradiated with protons to areas of gross disease only, using 51 cobalt gray equivalents (CGE) in 10 fractions (protocol 1). Fifteen patients with stage I-IIIA NSCLC and FEV(1) > 1.0 L received 45-Gy photon irradiation to the primary lung tumor and the mediastinum, plus a 28.8-CGE proton boost to the gross tumor volume (protocol 2).

MEASUREMENTS

Pulmonary function was evaluated prior to treatment and 1 month, 3 months, and 6 to 12 months following irradiation.

RESULTS

In patients receiving protocol 1, no significant changes in pulmonary function occurred. In patients receiving protocol 2, at 6 to 12 months, the diffusion capacity of the lung for carbon monoxide had declined from 61% of predicted to 45% of predicted (p < 0.05), total lung capacity had declined from 114% of predicted to 95% of predicted (p < 0.05), and residual volume had declined from 160% of predicted to 132% of predicted (p < 0.05). Airway resistance increased from 3.8 to 5.2 cm H(2)O/L/s (p < 0.05). No statistically significant changes occurred in vital capacity, FEV(1), or PaO(2).

CONCLUSIONS

Our observations indicate that it is feasible to apply higher-than-conventional doses of radiation at a higher-than-conventional dose per fraction without excess pulmonary toxicity when conformal radiation techniques with protons are used.

Relating radiation-induced regional lung injury to changes in pulmonary function tests

PURPOSE

To determine whether the sum of radiotherapy (RT)-induced reductions in regional lung perfusion is quantitatively related to changes in global lung function as assessed by reductions in pulmonary function tests (PFTs).

METHODS AND MATERIALS

Two hundred seven patients (70% with lung cancer) who received incidental partial lung irradiation underwent PFTs (forced expiratory volume in 1 s and diffusion capacity for carbon monoxide) before and repeatedly after RT as part of a prospective clinical study. Regional lung function was serially assessed before and after RT by single photon emission computed tomography perfusion scans. Of these, 53 patients had 105 post-RT evaluations of changes in both regional perfusion and PFTs, were without evidence of intrathoracic disease recurrence that might influence regional perfusion and PFT findings, and were not taking steroids. The summation of the regional functional perfusion changes were compared with changes in PFTs using linear regression analysis.

RESULTS

Follow-up ranged from 3 to 86 months (median 19). Overall, a significant correlation was found between the sum of changes in regional perfusion and the changes in the PFTs (p = 0.002-0.24, depending on the particular PFT index). However, the correlation coefficients were small (r = 0.16-0.41).

CONCLUSIONS

A statistically significant correlation was found between RT-induced changes in regional function (i.e., perfusion) and global function (i.e., PFTs). However, the correlation coefficients are low, making it difficult to relate changes in perfusion to changes in the PFT results. Thus, with our current techniques, the prediction of changes in perfusion alone does not appear to be sufficient to predict the changes in PFTs accurately. Additional studies to clarify the relationship between regional and global lung injury are needed.

Can we predict radiation-induced changes in pulmonary function based on the sum of predicted regional dysfunction?

PURPOSE

To determine whether changes in whole-lung pulmonary function test (PFT) values are related to the sum of predicted radiation therapy (RT)-induced changes in regional lung perfusion.

PATIENTS AND METHODS

Between 1991 and 1998, 96 patients (61% with lung cancer) who were receiving incidental partial lung irradiation were studied prospectively. The patients were assessed with pre- and post-RT PFTs (forced expiratory volume in one second [FEV1] and diffusion capacity for carbon monoxide [DLCO]) for at least a 6-month follow-up period, and patients were excluded if it was determined that intrathoracic recurrence had an impact on lung function. The maximal declines in PFT values were noted. A dose-response model based on RT-induced reduction in regional perfusion (function) was used to predict regional dysfunction. The predicted decline in pulmonary function was calculated as the weighted sum of the predicted regional injuries: equation [see text] where Vd is the volume of lung irradiated to dose d, and Rd is the reduction in regional perfusion anticipated at dose d.

RESULTS

The relationship between the predicted and measured reduction in PFT values was significant for uncorrected DLCO (P = .005) and borderline significant for DLCO (P = .06) and FEV1 (P = .08). However, the correlation coefficients were small (range,.18 to.30). In patients with lung cancer, the correlation coefficients improved as the number of follow-up evaluations increased (range,.43 to.60), especially when patients with hypoperfusion in the lung adjacent to a central mediastinal/hilar thoracic mass were excluded (range,.59 to.91).

CONCLUSION

The sum of predicted RT-induced changes in regional perfusion is related to RT-induced changes in pulmonary function. In many patients, however, the percentage of variation explained is small, which renders accurate predictions difficult.

Radiation dose-effect relations and local recovery in perfusion for patients with non-small-cell lung cancer

PURPOSE

To determine local dose-effect relations for lung perfusion and density changes due to irradiation for patients with non-small-cell lung cancer (NSCLC) and to quantify the effect of reperfusion.

METHODS AND MATERIALS

For 25 NSCLC patients and a reference group of 81 patients with healthy lungs, registered single photon emission computed tomography (SPECT) lung perfusion and CT scans were made, before and after radiotherapy. Average dose-effect relations for perfusion and CT-density changes were calculated and compared with the dose-effect relation of the reference group. On the basis of these dose-effect relations, the post-RT perfusion was predicted for each patient and compared to the measured post-RT perfusion.

RESULTS

Well-perfused lung regions of the NSCLC patients showed the same dose-effect relation as the reference patients. By comparing predicted and measured post-treatment perfusion scans, regions of reperfusion could be determined for 18 of 25 NSCLC patients but for none of the reference patients.

CONCLUSION

Well-perfused lung tissue of patients with NSCLC behaves like healthy lung tissue with respect to radiation. The dose-effect relation for perfusion and CT density was extended for doses up to 80 Gy. Radiation damage in poorly perfused lung regions was less than predicted as a consequence of local reperfusion.

The effect of patient-specific factors on radiation-induced regional lung injury

PURPOSE

To assess the impact of patient-specific factors on radiation (RT)-induced reductions in regional lung perfusion.

METHODS

Fifty patients (32 lung carcinoma, 7 Hodgkin's disease, 9 breast carcinoma and 2 other thoracic tumors) had pre-RT and > or = 24-week post-RT single photon emission computed tomography (SPECT) perfusion images to assess the dose dependence of RT-induced reductions in regional lung perfusion. The SPECT data were analyzed using a normalized and non-normalized approach. Furthermore, two different mathematical methods were used to assess the impact of patient-specific factors on the dose-response curve (DRC). First, DRCs for different patient subgroups were generated and compared. Second, in a more formal statistical approach, individual DRCs for regional lung injury for each patient were fit to a linear-quadratic model (reduction = coefficient 1 x dose + coefficient 2 x dose2). Multiple patient-specific factors including tobacco history, pre-RT diffusion capacity to carbon monoxide (DLCO), transforming growth factor-beta (TGF-beta), chemotherapy exposure, disease type, and mean lung dose were explored in a multivariate analysis to assess their impact on the coefficients.

RESULTS

None of the variables tested had a consistent impact on the radiation sensitivity of regional lung (i.e., the slope of the DRC). In the formal statistical analysis, there was a suggestion of a slight increase in radiation sensitivity in the dose range >40 Gy for nonsmokers (vs. smokers) and in those receiving chemotherapy (vs. no chemotherapy). However, this finding was very dependent on the specific statistical and normalization method used.

CONCLUSION

Patient-specific factors do not have a dramatic effect on RT-induced reduction in regional lung perfusion. Additional studies are underway to better clarify this issue. We continue to postulate that patient-specific factors will impact on how the summation of regional injury translates into whole organ injury. Refinements in our methods to generate and compare SPECT scans are needed.

Intraoperative 125I brachytherapy for high-risk stage I non-small cell lung carcinoma

PURPOSE

Preliminary assessment of feasibility, efficacy, acute and chronic side effects associated with permanent intraoperative placement of 125I vicryl mesh brachytherapy in a select group of high-risk Stage I NSCLC who have undergone video-assisted thoracoscopic resection (VATR).

METHODS AND MATERIALS

From January 8, 1997 to March 16, 1998, 23 patients with Stage I NSCLC at high risk for conventional surgery due to cardiopulmonary compromise underwent combined VATR and intraoperative placement of 125I seeds embedded in vicryl mesh. Seeds embedded in vicryl suture were attached with surgical clips to a sheet of vicryl mesh, and thoracoscopically inserted over the target area (tumor bed and staple line) with nonabsorbable suture or surgical clips. A total dose of 100-120 Gy prescribed to the periphery of the target area (defined as the staple line and tumor bed with a 1-cm margin) was delivered.

RESULTS

The mean target area covered was 48 cm2 (range 40-72) and mean total activity was 22 mCi (range 17.2-28.2). The median length of postoperative stay was 7 days. The median follow-up was 11 months (range 2-20). Postoperative CT scans of the chest revealed no dislodgement of the seeds and no local recurrence in any patient. Three patients developed distant metastasis (1 died 6 months postoperatively; the other 2 are currently alive with disease). One patient developed an ipsilateral recurrence in the right lower lobe after having had a right upper lobe resection. There were 3 postoperative deaths due to medical comorbid conditions or surgical complications (1 in the immediate postoperative period). Pulmonary function testing performed 3 months after implantation revealed no significant difference between preoperative and postoperative values: mean preoperative FVC was 2.3 L (range 1.31-3.0) and postoperative FVC was 2.2 L (range 1.1-3.9), p = 0.42; mean preoperative FEV1 was 1.2 L (range 0.71-2.2), and postoperative FEV1 was 1.5 L (range 0.8-2.9), p = 0.28.

CONCLUSION

Review of early data suggests that intraoperative 125I vicryl mesh brachytherapy in high-risk Stage I NSCLC is potentially effective and well tolerated, with no significant decline in measurable pulmonary function studies and no increase in postoperative complications. Longer follow-up is needed to determine ultimate local control and survival.

Prediction of overall pulmonary function loss in relation to the 3-D dose distribution for patients with breast cancer and malignant lymphoma

PURPOSE

To predict the changes in pulmonary function tests (PFTs) 3-4 months after radiotherapy based on the three-dimensional (3-D) dose distribution and taking into account patient- and treatment-related factors.

METHODS

For 81 patients with malignant lymphoma and breast cancer, PFTs (VA, VC, FEV1 and TL,COc) were performed prior to and 3-4 months after irradiation and dose-effect relations for early changes in local perfusion, ventilation and air-filled fraction were determined using correlated CT and SPECT data. The 3-D dose distribution of each patient was converted into four different dose-volume parameters, i.e. the mean dose in the lung and three overall response parameters (ORPs, which represent the average local injury over the complete lung). ORPs were determined using the dose-effect relations for early changes in local perfusion, ventilation and air-filled fraction. Correlation coefficients were calculated between these dose-volume parameters and the changes in PFTs. In addition, the impact of the variables chemotherapy (MOPP/ABV and CMF), tamoxifen, smoking, age and gender on the relation between the mean lung dose and the relative changes in PFTs following radiotherapy was studied using multiple regression analysis.

RESULTS

The mean lung dose proved to be the easiest parameter to predict the reduction in PFTs 3-4 months following radiotherapy. For all patients the relation between the mean lung dose and the changes in PFTs could be described with one regression line through the origin and a slope of 1% reduction in PFT for each increase of 1 Gy in mean lung dose. Smoking and CMF chemotherapy influenced the reduction in PFTs significantly for VA and TL,COc, respectively. Patients treated with MOPP/ABV prior to radiotherapy had lower pre-radiotherapy PFTs than other patient groups, but did not show further deterioration after radiotherapy (at 3-4 months).

CONCLUSIONS

The relative reduction in VA, VC, FEV1 and TL,COc 3-4 months after radiotherapy for breast cancer and malignant lymphoma can be estimated before radiotherapy based on the mean lung dose of each individual patient and taking into account the use of chemotherapy and smoking habits of the patient.

Physical and biological predictors of changes in whole-lung function following thoracic irradiation

PURPOSE

To develop methods of predicting the pulmonary consequences of thoracic irradiation (RT) by prospectively studying changes in pulmonary function following RT.

METHODS AND MATERIALS

100 patients receiving incidental partial-lung irradiation during treatment of tumors in or adjacent to the thorax had whole-lung function assessed via symptoms and pulmonary function tests (PFTs: FEV1-forced expiratory volume 1 s; DLCO-diffusion capacity) before and repeatedly 6-48 months following RT. All had computed tomography-based three-dimensional (3D) dose calculations with lung density heterogeneity corrections for dose-volume histogram (DVH) and normal tissue complication probability (NTCP) calculations. Functional DVHs (DVfH) based on SPECT (single photon emission computed tomography) lung perfusion scans, and serial transforming growth factor-beta (TGF-beta1) levels were available in 50 and 48 patients, respectively. The incidence and severity of changes in whole-lung function were correlated with clinical, physical, and biological factors. Exploratory statistical analyses were performed using chi-square, Pearson correlations, logistic regression, and multiple linear regression.

RESULTS

RT-induced symptoms developed in 21 patients. In the overall group, the single best predictor for the development of symptoms was the NTCP (p < 0.05). Pre-RT PFTs alone were less predictive (p = 0.1 for FEV1, p = 0.08 for DLCO). A multivariate model based on pre-RT DLCO and CT-based NTCP was strongly predictive for the development of symptoms (p < 0.001). NTCPs based on SPECT-derived DVf Hs and TGF-beta1 levels did not appear to provide additional predictive value. The presence or absence of pulmonary symptoms was correlated with the decline in PFT 6 months following RT (p < 0.05). In the overall group, the degree of decline in PFTs was not well correlated with any of the dose-volume variables considered. In patients with "good" pre-RT PFTs, there was a relationship between the percent reduction in PFT and dose-volume parameters such as the percent of lung volume receiving > 30 Gy (p < 0.05).

CONCLUSION

The extent of alteration in whole-lung function (symptoms or PFT changes) appears to be related to both dose-volume and pre-RT PFT parameters. The data suggest that no one variable is likely to be an adequate predictor and that multivariate predictive models will be needed. Additional studies are underway to develop better predictive models that consider physical factors such as the DVH and regional perfusion, as well as biological/clinical factors such as pre-RT PFTs and TGF-beta1.

Early and late morbidity in patients undergoing pulmonary resection with low diffusion capacity

BACKGROUND

We sought to determine whether low diffusion capacity of the lung to carbon monoxide (DLCO) is a predictor of high postoperative mortality and morbidity after major pulmonary resection and whether major pulmonary resection in patients with low DLCO results in substantial long-term morbidity.

METHODS

Sixty-two major pulmonary resections were performed in 61 patients with low DLCO (DLCO < or = 60% predicted for pneumonectomy or bilobectomy; < or = 50% predicted for lobectomy). Contemporaneously, 262 other patients underwent 263 major pulmonary resections (group II). Long-term morbidity was assessed in subsets of patients with low (n = 24) and high (n = 22; DLCO > 60% predicted) DLCO.

RESULTS

The hospital mortality rates were equivalent (4.8% low DLCO versus 4.9% group II), whereas respiratory complications were more frequent in patients with low DLCO (18% versus 9.5%; p = 0.05). In the subgroup analyses, patients with low DLCO had more hospitalizations for respiratory compromise and worse median dyspnea scores. Analysis of patients with substantial dyspnea revealed an association with extended pulmonary resection and postoperative radiation therapy in patients with low DLCO.

CONCLUSIONS

Patients with low DLCO underwent major pulmonary resection with a low mortality rate and an acceptable, but increased, respiratory complication rate. Long-term respiratory morbidity was increased in patients with low DLCO; however, the extent of pulmonary resection and the use of postoperative radiation therapy may have contributed to the development of dyspnea in these patients.