Autofluorescence detection of tumors in the human lung--spectroscopical measurements in situ, in an in vivo model and in vitro

To detect bronchial carcinoma by autofluorescence, we measured the spectra of tumor and normal tissue in situ, in an in vivo model and in vitro by fiber optic spectrometer and two-dimensional resolved microspectroscopy. The in situ measurements were performed in bronchi of nine patients with squamous cell carcinoma during regular bronchoscopy with autofluorescence assistance. The fluorescence was monitored with a fiber optical spectrometer under blue light excitation (lambda=405nm). In an in vivo model, the resected lobe of a lung was perfused under physiological conditions. Tumorous and normal tissues were examined spectroscopically during perfusion and after blood removal and substitution with formol. In another setup the wavelength dependency of autofluorescence was examined on resected parts of physiological bronchi and central bronchial carcinomas. Under the variation of the excitation from 385 to 465nm the autofluorescence response was monitored with a fiber optic spectrometer. For investigation of the origin of autofluorescence, two-dimensional resolved spectroscopy was performed with the SpectraCube system on several sections of tumor and normal tissues All measurements, performed in vivo, in the in vivo model and in vitro agreed, that the main difference of the autofluorescence between tumor and normal bronchus tissue is the intensity of the fluorescences' main peak at 505nm. The signal on tumor tissue is in all cases significantly lower than that of normal tissue. The shape of the autofluorescence peaks is in healthy and carcinoma tissue approximately the same with two characteristic minima at 540 and 580nm. After the preparation with formaldehyde those minima disappeared from the spectra. A comparison with the absorption spectra of hemoglobin showed, that the variation of the spectra may be due to the blood content in the tissue. Two-dimensional spatially resolved spectroscopy showed, that the lower intensity of fluorescence in tumor tissue is due to the irregular and low-concentrated formation of fluorescent structures, which seen to be the elastic structures of bronchial tissue.

Ion mobility spectrometry in the diagnosis of sarcoidosis: results of a feasibility study

A feasibility study with ion mobility spectrometry (IMS) was started to find characteristic peaks of volatile organic compounds in exhaled air of 10 mL sampling volume, which might be relevant for the diagnosis of sarcoidosis. Therefore, breath samples of 9 patients with sarcoidosis and suspicion of sarcoidosis because of mediastinal lymph node enlargement were investigated. The 5 patients with confirmed sarcoidosis showed a highly congruent distribution of metabolites in exhaled air which was different in main component analyses from patients with unspecific mediastinal lymph node enlargement. These results are a first step in breath analysis by IMS in patients with sarcoidosis. The IMS as a new method in breath analysis and the first results of the investigations are presented and discussed in detail.

A proposed classification system of central airway stenosis

Tracheobronchial stenosis, a serious problem in adults and children, has multiple causes and has been treated in many ways. While developing an international multicentre study to evaluate efficacy of airway stents, it was realised that no adequate description of central airway stenosis regarding type, location and degree has been published. Thus, comparing results of different treatment modalities in different centres has been difficult due to a lack of uniformity of classification. Reports are typically descriptive and precise classification schemes have not adequately addressed either for the trachea or the main bronchi. A standardised classification scheme was proposed with descriptive images and diagrams for rapid and uniform classification of central airway stenosis. The present authors' system divides stenosis into structural and dynamic types and further classifies the disease by degree of stenosis, location and transition zone. Multiple sites can be described and each is transformed into a simple numerical scoring system prompted by a diagram, which can be easily captured for subsequent uniform analysis across sites. A pilot validation of the system, with 18 pulmonologists of varying training background, showed strong precision and agreement between observers. Such a system will enhance the ability to study the effectiveness of treatment modalities for central airway stenosis.

Therapeutic bronchoscopy with immediate effect: laser, electrocautery, argon plasma coagulation and stents

Minimally invasive diagnostic and therapeutic approaches in medicine have been applied for a more selective and tailored approach to reduce patients' morbidity and mortality. The efficacy of interventional pulmonology for palliation of patients with central airways obstruction has been established and its curative potential for intralesional treatment of early cancer has raised great interest in current screening programmes. This is due to the fact that surgical resection and systemic nodal dissection as the gold standard is relatively morbid and risky, especially when dealing with individuals with limited functional reserves due to smoking-related comorbidities, such as chronic obstructive pulmonary disease. Furthermore, such comorbidities have been proven to harbour early stage lesions of several millimetres in size without involvement of nodal disease that may be amenable to local bronchoscopic treatment. Therefore, the success of minimally invasive strategies for palliation and treatment with curative intent strongly depends on the diligent identification of the various factors in lung cancer management, including full comprehension of the limits and potential of each particular technique. Maximal preservation of quality of life is a prerequisite in successfully dealing with individuals at risk of harbouring asymptomatic early lung cancer, to prevent aggressive surgical diagnostic and therapeutic strategies since overdiagnosis remains an issue that is heavily debated. In the palliative setting of alleviating central airway obstruction, laser resection, electrocautery, argon plasma coagulation and stenting are techniques that can provide immediate relief, in contrast to cryotherapy, brachytherapy and photodynamic therapy with delayed effects. With curative intent, intraluminal techniques that easily coagulate early stage cancer lesions will increase the implementation of interventional pulmonology for benign and relatively benign diseases, as well as early cancer lesions and its precursors at their earliest stage of disease.

[Survival and pattern of failure in palliative endobronchial HDR -- brachytherapy using iridium 192 in recurring bronchial carcinoma]

To evaluate the impact of palliative high dose rate brachytherapy on survival and a pattern of failure, we performed a matched pair study. 94 patients with tumor recurrence after external beam radiation received endobronchial brachytherapy. They were followed prospectively and matched retrospectively with 94 comparable patients who had not received brachytherapy. Matched parameters were age, gender, smoking behaviour, histology, tumor stage, EBRT-dose and fractionation. The leading cause of death in both groups was generalized tumor growth. In the combined therapy group, fatal hemorrage was 27.7 %, two and a half times higher than in the EBRT group with 10.6 %, whereas respiratory insufficiency in the brachytherapy group was 6.4 % and 11.7 % in the EBRT group. A complete remission after brachytherapy yielded a 10.5 months longer mean survival. Patients dying from fatal hemorrhage after endobronchial brachytherapy lived on average 10.2 months longer than matched EBRT patients dying from the same cause. Analyzing the time-course of fatal hemorrage in the brachytherapy group we conclude that - because of its early onset in the first 10 months after induction of therapy roughly 20 % of the deaths can be attributed to a radiation damage. In those patients who died after 10 months the major cause of fatal hemorrhage was the natural course of sqamous cell carcinoma with prolonged survival.

Sequential photodynamic therapy (PDT) and high dose brachytherapy for endobronchial tumour control in patients with limited bronchogenic carcinoma

BACKGROUND

Bulky endobronchial tumours in patients with lung cancer are difficult to treat. Brachytherapy and photodynamic therapy (PDT) are variably effective, and the combination of these treatments is not often recommended. However, cell culture studies and animal studies indicate a possible synergistic effect of combining PDT with ionising radiation. We assessed the safety and effectiveness of combined brachytherapy and PDT in patients with bulky endobronchial lung cancer.

METHODS

Patients with histologically proven non-small cell bronchogenic carcinoma and bulky endobronchial tumours were treated using a combination of PDT (Photofrin, 2 mg/kg) and brachytherapy. Six weeks after PDT, brachytherapy was applied with five fractions of 4 Gy at weekly intervals. Follow up was performed with standard and autofluorescence bronchoscopy and tissue biopsies every 3 months.

RESULTS

Thirty two patients were treated. Tumours were extensive with lengths ranging from 10 to 60 mm along the bronchus and estimated volumes ranging from 40 to 3500 mm3. At a mean follow up of 24 months, 26 patients were free of residual tumour and local recurrence. The remaining patients received a second treatment with PDT, brachytherapy, Nd:YAG laser coagulation, or external beam radiation. Distant metastases (lung, lymph node) developed in two of the six patients. Currently, all 32 patients are well. There is no evidence of residual or local recurrent endobronchial cancer in 28 patients and none had severe complications.

CONCLUSION

The combination of PDT and brachytherapy for treating patients with lung cancer and extensive endobronchial tumour is safe and, in this study, had excellent therapeutic efficacy.

[Hemoptysis]

Hemoptysis is a potentially life-threatening complication of various diseases. The most common causes are infectious and inflammatory processes, followed by neoplasms, pulmonary embolisms, mitral stenoses, coagulopathies, and multiple systemic disorders. Primary examinations include a chest x-ray, an angio CT and a bronchoscopy. Sometimes, a bronchial artery angiogram is required. The patient is at risk of suffocation because blood and clots can severely obstruct his airways. Thus, the most important measures are: supplemental oxygen, positioning the patient with the bleeding side down, bronchoscopical suctioning and removal of blood and clots. Coagulopathies have to be corrected. Application of vasoactive drugs may help temporarily. In cases of bleeding from central lesions, coagulation with laser or argon-plasma-coagulator is feasible. Heavy bleeding from the periphery requires a balloon or tube tamponade. Depending on the cause and the severity of the bleeding either anti-inflammatory medical treatment, hemostyptic radiation therapy, bronchial artery embolisation or a surgical procedure must follow.

[Airway manifestations of relapsing polychondritis: treatment with cyclophosphamide and placement of bronchial stents]

We report the case of a 41-year-old female patient with relapsing polychondritis and severe respiratory involvement. The patient presented with acute respiratory failure requiring endotracheal intubation. Bronchoscopy revealed tracheal collapse and inflammatory stenoses with dynamic collapse of the major airways. We describe a multidisciplinary therapeutic approach, consisting of immunosuppressive treatment, bronchoscopic placement of self-expandable stents into the collapsing bronchi, and tracheotomy. In addition, we report the effectiveness of oral cyclophosphamide for treatment of relapsing polychondritis with severe respiratory involvement after failure of other immunosuppressive agents. The problem of severe respiratory complications in patients with relapsing polychondritis and the need for a multidisciplinary approach is discussed.

[Undetected tracheal tumours responsible for ventilator-dependency]

HISTORY AND CLINICAL FINDINGS

Case 1 A patient with former carcinoma of the larynx became dependent on mechanical ventilation. She failed to be weaned from the respirator because of severe bronchial obstruction, therefore she was transferred to a weaning center. Case 2 A COPD patient with respirator dependency due to infectious exacerbation underwent percutaneous tracheostomy shortly after primary intubation. Status asthmaticus was considered to be the reason of following unsuccessful weaning.

INVESTIGATIONS, DIAGNOSIS AND TREATMENT

Case 1 Performing a bronchoscopy the diagnosis of a central tumor (local recurrence) was found causing nearly total obstruction of the trachea. The ensuing treatment was restricted to palliation. Case 2 After transferral to the weaning center a small cell lung cancer located in the central tracheal was identified by bronchoscopy. The tumor masses were exstirpated by laser technique and the patient was weaned immediately afterwards. Chemotherapy and radiation of the mediastinum were performed.

CONCLUSIONS

Fibreoptic bronchoscopy is an essential tool concerning diagnosis and treatment of tracheal tumors which may cause difficult weaning from mechanical ventilation. Every percutaneous tracheostomy should be performed with endoscopical guidance.

[Surfactant--treatment of complete lobar atelectasis after exacerbation of bronchial asthma by infection]

Dysfunction of airway surfactant is suggested as an important factor contributing to the pathogenesis of bronchoconstriction of patients with asthma. We report the case of a 59-year-old female who had an infect-exacerbation of her asthma complicated by a complete collapse of the left lower lung lobe. Only the local application of 150 mg of bovine surfactant resulted in a complete reexpansion of the lobe. Local therapy with replacement of surfactant may be a promising therapeutic approach in treatment of forms of atelectasis, which depend on a dysfunction or disturbed homeostasis of surfactant.

[A new rigid bronchoscope with a measuring tube for pressure and capnometry]

BACKGROUND

Pulmonary gas exchange under jet ventilation is usually controlled by pulse-oxymetry and blood gas analysis. Capnometry is not common in clinical use. Rigid bronchoscopes with pressure measurements are not known. Our aim was the development of a rigid bronchoscope with a built-in tube for the online measurement of airway pressure and gas composition.

METHODS

We measured the distribution of inspiratory pressure under jet ventilation over the length inside a 8 x 400 mm rigid bronchoscope in a lung model and in patients. A measuring tube was constructed for obtaining representative values of airway pressure and capnometry. Using a prototype of a new rigid bronchoscope with the built-in measuring tube (R. Wolf Company, Knittlingen, Germany) inspiratory pressure and expiratory CO2 were measured during interventional bronchoscopy. The measuring tube was connected to the pressure control port of the jet ventilator. We applied jet ventilation with frequencies of 10 to 12 pulses per minute.

RESULTS

The inspiratory pressure reaches after 10 cm distally the instrumental port a significant constant plateau. Via the built-in measuring tube representative measurement of pressure and gas can be made there. The correlation between arterial CO2 (paCO2) and expiratory CO2 (petCO2) was excellent (r = 0.96). To maintain normocapnia in 25 patients undergoing interventional bronchoscopy, the jet pressure had to be adjusted to values between 0.5 and 3.5 bar (median 2.5 bar). The responding inspiratory pressure varied from 3 to 25 mbar (median 15 mbar). A flexible bronchoscope in the working channel raises the airway pressure from 18 to 23 mbar. The automatic interruption of the jet-pulses by connecting the measuring tube to the pressure control port of the ventilator in order to prevent a barotrauma was found feasible.

CONCLUSIONS

Simultaneous online control of airway pressure and gas is possible with the new rigid bronchoscope. Pressure depending jet ventilators can be controlled via the measuring tube to minimise the risk of barotrauma.

[Argon plasma coagulation in bronchology: a new method--alternative or complementary?]

Argon plasma coagulation (APC) is a thermal coagulation technique that uses ionized argon to transmit high-frequency electrical current, contact free, to tissue. APC has been used in surgery for more than 20 years, particularly for the hemostasis of superficial bleeding. Although APC has become well established in gastrointestinal endoscopy since its introduction in 1991, very few reports of its use in bronchoscopy exist to date. From June 1994 to June 1998, 364 patients (80 women, 284 men), 88% with a confirmed malignant tumor, were treated prospectively in a total of 482 sessions. The single most common indication was recanalization of malignant airway stenoses (186 patients). The defined therapy objective was achieved with good results in 67% of patients. More than 90% of interventions were performed with rigid bronchoscopy. Despite less penetration compared with Nd:YAG laser, extensive bronchial tumors were treatable, in which coagulated tumor fractions were removed either with forceps or bronchoscope tip. The second indication was bleeding in the central airways (119 patients). Acute hemostasis was achieved in 118 patients, 20% in whom the flexible technique under local anesthesia was used. In 34 patients, APC was successfully used to recanalize occluded stents. Rare indications included benign endobronchial tumor, fistula conditioning before fibrin adhesion, and the treatment of scar tissue stenosis. Summarizing all complications, a rate of 3.7% "per treatment" was recorded. Two patients died within 24 hours; their deaths were not directly related to APC. APC is an effective and safe technique for the treatment of bronchologic tumor ablation and hemostasis and can be used with local anaesthetic with flexible bronchoscopy or rigid bronchoscopy with general anesthesia. Compared with Nd:YAG laser, APC is an economic alternative technique offering more effective hemostasis. Furthermore, APC is of particular value as a compliment to well-known techniques, increasing the options in interventional bronchoscopy.

[Pharmacokinetics of cyclophosphamide, adriamycin and adriamycin prodrug (HMR 1928) using an ex vivo isolated perfused human lung model (IHLP)]

BACKGROUND

Today knowledge about pharmacokinetics of anticancer drugs in human malignant tumors is poor. Data from in vivo studies are limited and difficult to obtain due to ethical aspects. An ex vivo isolated perfused and ventilated human lung model however allows pharmacological studies of human bronchial carcinoma inside their host organ, the lung, under physiological conditions without compromising the patient.

METHODS

Following surgery for bronchial carcinoma human lung preparations were reperfused and ventilated extracorporally for 2-3 hours. During the reperfusion anticancer drugs are added to the perfusion solution and their uptake into tumor, normal lung tissue, and lymph nodes is studied.

RESULTS

An initial study showed that lung reperfusion under physiological circumstances over a period of 2-3 hours did not interfere with histo-pathological diagnostics and staging; an important precondition for potential adjuvant treatment. Pharmacokinetics of cyclophosphamid, adriamycin, and a water soluble adriamycin prodrug (HMR 1826) were measured. Final tissue concentrations of adriamycin and cyclophosphamid in peripheral lung parenchyma turned out to be 10 times higher compared to tumor tissue. However, following perfusion with adriamycin prodrug final tissue concentrations of adriamycin were in the same range in lung and tumor.

CONCLUSIONS

The ex-vivo isolated human lung perfusion model (IHLP) has proven to be an ideal scientific model for pharmacological investigations of human tumors as an intermediate step between cell culture and in-vivo situation without any disadvantage for the patient. The tumor-to-host interaction is completely saved in this model. However, first pass reactions of drugs in other organs must not play a role for the substances studied with the IHLP. The role and future applications of the isolated perfused human lung model for other indications is discussed.

[High-dose, stereotactic, one-time radiotherapy with curative intent for peripheral lung cancer]

In peripheral non small cell lung cancer without metastasis, surgical resection achieves 5-year survival rates of at least 65%. In functionally inoperable patients radiation therapy offers the second best changes. However, in cases of severe emphysema with severely limited lung function even conventional radiation therapy is prohibited because of possible fibrotic reactions of the lung parenchyma. For such patients high dose rate stereotactic one-time radiation therapy may be an option. According to the study protocol of the DKFZ Heidelberg a dose rate of 24 Gy at the iso-center is applied with the linear accelerator in a single session. The recognisable tumour is irradiated with 22 Gy (90% isodose included). 20 Gy are applied to the tumour plus 6 millimeters safety margin. Prerequisites of such a therapy are a detailed computer-based planning using CT scans and an exact positioning with immobilisation of the patient. The irradiation is ideally performed under general anesthesia with high-frequency jetventilation to avoid movements due to breathing. We report on this new therapeutic modality in a patient with lung emphysema having a T2 tumour.

[Telomerase in lung cancer. Testing the activity of the "immortaligy enzyme" bronchial biopsies increases the diagnostic yield in cases of suspected peripheral bronchogenic carcinomas]

The proliferative capability is time-limited in normal somatic cells by the shortening of their chromosomal ends, the telomeres (Hayflick limit). An important feature of malignant cells is their immortality. The probably most common mechanism of tumour cells to achieve unlimited replicability is the activation of the enzyme telomerase. The reverse transcriptase can compensate the loss of telomeres. Using a PCR-based TRAP assay we found telomerase activity in tumour biopsies, exsudates and bronchial washings in various thoracic malignancies. In 38 of 47 patients with suspected peripheral lung cancer eventually surgery or invasive procedures proved a malignancy. In fluoroscopically guided bronchial brushings from 25 of these 38 patients (66%) the TRAP assay revealed telomerase activity. There was a single false positive case (tuberculosis) and with a single exception, the simultaneously taken brushes of the contralateral lobes were all telomerase negative. In 23 patients (61%) tumour cells were found in the cytological examination. In 33 patients at least one marker was positive. Thus the combination of cytology and telomerase test in bronchial brush biopsies attained a diagnostic yield of 87%.

[Mediastinoscopy in the staging of bronchial carcinoma--a critical assessment]

BACKGROUND

Mediastinoscopy has a high sensitivity for lymph node staging with a specificity of 100%. This compensates the disadvantage of being an invasive procedure compared to CT and PET scan. Although many studies examined the sensitivity, rate of complications and costs no data have been published concerning interindividual differences in relation to the surgeon performing the operation.

METHODS

From 6/98 to 12/99 in a prospective study all biopsied lymph nodes were documented. Histopathologic results of mediastinoscopy and the following operation were correlated with the 6 participating surgeons. From these data the sensitivity of mediastinoscopy for preoperative lymph node staging was analysed.

RESULTS

Analysis of 165 mediastinoscopies showed an overall sensitivity of 80.6%. 4.1 lymph nodes were biopsied per patient. Substantial differences were noted for individual biopsy patterns between surgeons, but surgeon-related sensitivity was similar. Lymph nodes 7 were reached in 15.2% to 90.9% and 2 left in 39.4% to 84.4%, whereas lymph nodes 4 were biopsied at similar rates by all surgeons.

CONCLUSION

The variable "surgeon" can be neglected if a sufficient number of lymph nodes is biopsied. Despite individual biopsy patter mediastinoscopy has a higher sensitivity than CT scan and is still the method for choice of preoperative staging. Internal quality control in thoracic surgery departments is desirable.

Modeling expiratory flow from excised tracheal tube laws

Flow limitation during forced exhalation and gas trapping during high-frequency ventilation are affected by upstream viscous losses and by the relationship between transmural pressure (Ptm) and cross-sectional area (A(tr)) of the airways, i.e., tube law (TL). Our objective was to test the validity of a simple lumped-parameter model of expiratory flow limitation, including the measured TL, static pressure recovery, and upstream viscous losses. To accomplish this objective, we assessed the TLs of various excised animal tracheae in controlled conditions of quasi-static (no flow) and steady forced expiratory flow. A(tr) was measured from digitized images of inner tracheal walls delineated by transillumination at an axial location defining the minimal area during forced expiratory flow. Tracheal TLs followed closely the exponential form proposed by Shapiro (A. H. Shapiro. J. Biomech. Eng. 99: 126-147, 1977) for elastic tubes: Ptm = K(p) [(A(tr)/A(tr0))(-n) - 1], where A(tr0) is A(tr) at Ptm = 0 and K(p) is a parametric factor related to the stiffness of the tube wall. Using these TLs, we found that the simple model of expiratory flow limitation described well the experimental data. Independent of upstream resistance, all tracheae with an exponent n < 2 experienced flow limitation, whereas a trachea with n > 2 did not. Upstream viscous losses, as expected, reduced maximal expiratory flow. The TL measured under steady-flow conditions was stiffer than that measured under expiratory no-flow conditions, only if a significant static pressure recovery from the choke point to atmosphere was assumed in the measurement.

Impact of preoperative bimodality induction including twice-daily radiation on tumor regression and survival in stage III non-small-cell lung cancer

PURPOSE

The objective of this prospective study was to assess the feasibility, toxicity, and efficacy of an intensive trimodality approach in stage III non-small-cell lung cancer (NSCLC).

PATIENTS AND METHODS

Fifty-four patients with NSCLC and biopsy-proven N2 nodes (IIIA; n = 25) or N3 nodes or T4 lesions (IIIB; n = 29) were administered two initial cycles of ifosfamide, carboplatin, and etoposide; subsequent radiotherapy (45 Gy, twice-daily 1.5 Gy) with concurrent carboplatin and vindesine; and surgery if the patient's disease was resectable or conventional radiotherapy (16 Gy, 2 Gy/d) if the patient's disease was not resectable or incompletely resectable.

RESULTS

Thirty-seven patients (69%) responded to preoperative induction. Forty of 54 patients (74%) had disease that was resectable, with 34 (63%) complete resections (R0). A substantial pathologic response (tumor regression [TR] > 90%) was achieved in 27 of 54 patients (50%) and is revealed as an independent predictor for long-term survival after surgery. Five treatment-related deaths (9%) occurred. With a median follow-up period of 44 months, calculated survival rates at 3 years were 35% for patients with stage IIIA disease, 26% for patients with stage IIIB disease, and 56% for patients with R0 disease and TR > 90%.

CONCLUSION

This trimodality approach is feasible and results in encouraging 3-year survival rates in prognostically unfavorable patients with stage III NSCLC. Patients experiencing a 90% degree of pathologic TR were most likely to achieve long-term survival.

Trimodality therapy in stage III non-small cell lung cancer: prediction of recurrence by assessment of p185neu

In a trimodality treatment approach for stage III non-small cell lung cancer the prognostic impact of pretherapeutic p185neu assessment was evaluated. Fifty-four patients were admitted to chemotherapy followed by twice-daily radiation with concomittant low-dose chemotherapy and subsequent surgery. Immunohistochemical assessment of p185neu expression was performed in paraffin-embedded mediastinal lymph node metastases, by mediastinoscopy biopsy prior to therapy. Paraffin-embedded biopsies of mediastinal lymph node metastases were available in 33 cases. Seven out of eight patients with positive p185neu staining developed distant metastases, in contrast to seven out of 25 negative cases. Expression of p185neu in mediastinal lymph node metastases was a significant predictor for progression-free survival (p=0.047) and resulted mainly from significant differences in metastases-free survival (p185neu-positive versus p185neu-negative: median, 11 versus 19 months; 2- and 3-yr rates, 13% and 0% versus 40% and 32%; p=0.04). On the basis of these preliminary results it was concluded that further evaluation of p185neu expression in trials on neoadjuvant and adjuvant therapy is warranted. When the prognostic impact of p185neu in such trials with larger patient numbers is confirmed, this may contribute to the identification of stratification variables for future treatment approaches of non-small cell lung cancer.

Clinical evaluation of a new bifurcated dynamic airway stent: a 5-year experience with 135 patients

The Dynamic stent, a bifurcated airway prosthesis facilitating coughing, was clinically evaluated. The stents were inserted bronchoscopically in 135 patients (84 male, 51 female, age 12-90 years, mean 59 years) suffering from compression stenoses, strictures or malacias of the central airways, or tracheo-esophageal fistulas. Extrinsic compression from malignant and semi-malignant tumors was the leading indication for stenting (47.4%), followed by esophago-airway fistulas (22.2%) and post-intubation stenoses (14%). Stent insertion turned out to be very easy and could be performed without complications. The Dynamic stent was well tolerated and gave immediate relief of dyspnea in most cases. Follow-up data, three months after the last implantation revealed that at least 24 patients were still alive with a stent in place and free of complaints. In 27 cases, the stent had been removed after response to treatment. One of these patients received a second in order to seal a fistula, two months after removal of the first one. 85 patients, 79 with malignant, 6 with non-malignant diseases had died, with a mean survival time of 123 days (0 to 611 days). Complications directly attributable to the stent were rare. Two patients who had received the stent to counteract severe tracheal compression from aortic abnormalities died from arrosion and hemoptysis. There were no other severe complications. Cephalad migration occurred in 4/136 inserted stents. The Dynamic stent can be considered feasible, effective, and comparitively safe.

Management of malignant esophagotracheal fistulas with airway stenting and double stenting

Prognosis of inoperable or recurrent esophageal carcinoma is, at best, poor. Once an esophagotracheal fistula has developed, the overall condition of the patient declines rapidly. Aspiration pneumonia and severe coughing are common. The introduction of esophageal tubes does not always seal the fistula sufficiently and may compromise the airway causing stridor and dyspnea. In 30 patients (25 male, 5 female; age 23 to 74 years; mean, 56 years) with very large fistulas and airway problems, we inserted an airway stent (Dynamic) (n = 12) or an esophageal tube combined with a Dynamic airway stent (n = 18) with the aim of sealing the fistula and restoring patency of the airway and GI passage. The tracheobronchial Dynamic stent was chosen because its slightly concave, flexible posterior silicone membrane adapts ideally to the convex esophageal tube. The stents were well tolerated and significantly improved the quality of life. Of 30 patients, 16 could breathe and swallow unimpaired until shortly before their death. Moderate complaints persisted in five patients, dysphagia in eight patients, and dyspnea in one patient. Mean survival time in the double stent group was significantly greater (110 days) than in the airway stent-only group (24 days) or comparable groups in the literature treated with esophageal tubes only. We conclude that carefully selected patients can benefit from double stenting of esophagus and airways.

[Experiences with fluorescence diagnosis and photodynamic therapy in a multimodality therapy concept of operated, recurrent bronchial carcinoma]

Even of those few patients who are operated because of bronchial cancer up to a quarter develop a recurrence. One reason is certainly that tumor-cells already present at the time of surgery are bronchoscopically invisible. Fluorescence methods might be able to detect these malignant cells. For patients with post-surgical recurrences the therapeutical choices are limited due to the loss of parenchyma. Photodynamic therapy (PDT) with the hematoporphyrine derivative Photofrin is one laborious but promising option. Based on an argon-dye laser we have developed a combined system for the diagnostical measurement of autofluorescence and Photofrin-induced fluorescence at 488 nm and the therapeutical PDT at 630 nm. Under the excitation with blue light from the argon laser, differences in the autofluorescence of malignant and benign cells can be distinguished. Following the injection of Photofrin a spectrum peak at 628 nm clearly delineates tumor cells. In six out of twelve patients with post-surgical recurrences a single PDT course resulted in tumor eradication. With additional PDT courses and brachytherapies local tumor control could be achieved in all cases. The general photosensitivity and the necessary light protection were tolerated by all patients. In order to avoid severer complications such as asphyxia, obstruction of bronchi and pneumotharaces resulting from fibrin-plugs and necrotic tissue following PDT must be considered. Especially in patients with pneumonectomy a careful surveillance and debridement is mandatory.

The role of brachytherapy in the treatment and control of central bronchial carcinoma

Endobronchial brachytherapy is by far the oldest interventional bronchiological treatment procedure. In the decades following its inception in 1922, it has undergone progressive modification by innovations in radiation physics and techniques, and has enjoyed a renaissance with the introduction of fibreoptic bronchoscopy, local anaesthesia, modern afterloading devices, and high dose rate (HDR) treatment with iridium-192, an isotope with very high activity. However, there is little standardization of dose-specification, fractionation and optimal dosage using this isotope, and homogeneous, objective analyses of the clinical results of treatment using iridium-192 is lacking. Very often, the exact staging of patients is lacking. For such reasons, any evaluation of the efficacy of endobronchial brachytherapy is significantly impeded. However, reliable data are available on the palliative effect of HDR-brachytherapy, which is safe, fast in onset and apparently superior to external beam radiotherapy (EBRT) alone. In addition, some studies document the curative effects, or complications, offers not only an insight into the working principles of radiation treatment but also into the biological behaviour of bronchial tumours. Endobronchial HDR-brachytherapy should be compared to the other interventional procedures focusing on the same aim, namely that of restoring patency of a previously occluded bronchus. This is the overall challenge to pneumologists working in this field.

Respiratory failure due to tracheobronchomalacia

A case is described of tracheobronchomegaly progressing to extensive tracheomalacia, complicated by episodic choking, recurrent pulmonary infections, and irreversible hypercapnic respiratory failure. A Y-shaped tracheobronchial stent was placed endoscopically to splint the trachea open, with excellent clinical and physiological improvement. New stent designs may provide long term palliation in selected cases of diffuse tracheal collapse or stenosis, and offer an alternative to surgical repair.

Transsternal transpericardial operations in the treatment of bronchopleural fistulas after pneumonectomy

Between 1972 and 1993, 19 patients (15 males and 4 females) with bronchopleural fistulae and pleural empyema after pneumonectomy were treated with transsternal transpericardial operations and closure of the fistula. The underlying malignant disease was a non-small cell carcinoma in 12, a malignant epithelial mesothelioma in two, and an atypical carcinoid tumor in one case. One patient each presented with tuberculosis, chest trauma, and lung destroyed by bronchiectasis. Fistulas affected the right bronchial stump in 17, and the left in 2, cases after pneumonectomy. The time between pneumonectomy and transsternal transpericardial operation ranged between 1 month and 4 years. All patients were submitted to drainage and irrigation of the empyema cavity (2-4 weeks). In 16 patients a long bronchial stump was sutured or stapled, in three cases resection of a short stump with the distal trachea was followed by anastomosis of the trachea and left main stem bronchus. Irrigation of the pneumonectomy cavity was continued in all patients for 2 weeks. Transsternal transpericardial operation was successful in 15 patients. Two patients died in the first 30 days, of renal or respiratory failure without fistula recurrence. In two cases the fistula recurred; definitive healing was achieved using a great omentum flap and endoscopic application of fibrin glue and bone spongiosa. Transsternal transpericardial management of bronchus stump fistula after pneumonectomy is highly effective and offers advantages over the direct approach through the infected empyema cavity.

Experimental models of tracheobronchial stenoses: a useful tool for evaluating airway stents

BACKGROUND

Stent implantation is a conservative alternative to open operation for treating benign tracheobronchial strictures. Most of the presently available stents were primarily designed for endovascular use. Their respiratory use entails a risk of iatrogenic complications. From a scientific and from an ethical point of view these risks justify preclinical evaluation of new respiratory stents in experimental models of central airway stenoses. Therefore, an attempt was made to develop such models in piglets and adult minipigs.

METHODS

Tracheal stenoses were obtained by creating first a segmental tracheomalacia through extramucosal resection of cartilaginous arches. The fibrous component of the stenoses was then obtained through bronchoscopic application of a caustic agent causing progressive deep mucosal and submucosal injury. Stenoses of the main bronchi were created by topical application of the caustic agent only.

RESULTS

These models demonstrated the typical features of benign fibromalacic tracheobronchial stenoses with constant recurrence after mechanical dilation. Preliminary experiments showed that short-term problems of tolerance of stent prototypes are easily demonstrable in these models.

CONCLUSIONS

These experimental models, which simulate quite realistically human diseases, offer the opportunity to perfect new tracheobronchial stents specifically designed for respiratory use and to evaluate their long-term tolerance before their use in humans.

[The dynamic trachea stent for treatment of benign and malignant tracheal obstruction]

Severe obstruction of the trachea is a life-threatening condition. In two patients with a benign cause of obstruction, women of 70 and 71 years old, and in one with a malignant cause, a man of 24 years old, insertion of a dynamic trachea stent led to instant relief of symptoms. The dynamic stent has the advantage over rigid or self-expanding stents that it does not migrate but may be easily removed, that it induces less granulation tissue, and that less mucus retention is seen, because it allows the normal cough mechanism to take place.

Tracheal carcinoma and mixed pneumoconiosis. A causal relationship?

We report on a 58-year-old man who had worked as a plumber and fitter for over 41 years and had been exposed to asbestos, man-made mineral fibers and welding fumes. Eighteen months before death, squamous cell carcinoma of the trachea occurred. Energy-dispersive X-ray analysis revealed intrapulmonal dust deposits in accordance with his exposure. A relationship between the tracheal carcinoma and the dust exposure causing a mixed pneumonoconiosis seems to be probable.

Development of a new insertion technique and a new device for the placement of bifurcated airway stents

We developed a new insertion technique and designed a forceps device for the placement of bifurcated airway stents; 131 of 142 endoscopically placed tracheobronchial Y-stents were inserted with a forceps and a laryngoscope. For the last 52 stent implantations we used the new stent forceps. It was determined to be a simple and safe method without major complications. In 11 cases alternative techniques had to be used. Technique and device are described in detail.

Three years experience with a new balloon catheter for the management of haemoptysis

For the management of severe haemoptysis we have developed a double-lumen, bronchus-blocking catheter that can be introduced through the working channel of a standard fibrebronchoscope. We wondered whether this catheter would be suitable to control pulmonary haemorrhage in clinical practice. Over a period of 36 months, 30 of these catheters were used in 27 patients with moderate and massive pulmonary bleeding from various lesions. Underlying diseases were: malignancies (11), vascular deformities (5), tuberculosis (4), silicosis (2), carcinoids (2), silicosis (2), endometriosis (1), bronchiectasis (1). In 26 cases, the transbronchoscopic balloon tamponade was successful. In one patient, tumour growth close to the carina prevented securing of the balloon and double-lumen tube intubation was required. There were only minor complications attributable to the balloon. With the catheter in place for up to seven days, patients underwent surgery, received radiation, chemotherapy, drug treatment or bronchial arterial embolization. In conclusion, we found this double-lumen, bronchus-blocking device safe and the technique practicable to control pulmonary haemorrhage.

Theoretical and experimental basis for the development of a dynamic airway stent

Three major problems are currently associated with airway stents: mucostasis, formation of granulation tissue, and migration. We wanted to determine whether these problems could be solved by a different stent design. Based on theoretical considerations of an idealized trachea, we developed a dynamic bifurcation stent made of silicone which incorporates horseshoe-shaped steel struts. A flexible posterior membrane enables dynamic compression during cough, whilst the clasps maintain the airway lumen in the face of external compression. The design of the stent cast was based upon computed tomographic (CT)-scan studies of the central airways. Its complex shape provides a smoother distribution of pressure on the mucosa; thereby, lowering the stimulus for granulation formation. The bronchial limbs saddle on the carina, preventing displacement. The mechanical behaviours of the new stent and two commercially available stents were compared in an ex-vivo model, utilizing freshly excised tracheae and new visualization techniques. Dynamic (artificial coughs) and static loads (simulating tumour compression or pleural pressures) were applied on excised human tracheae with different stents. Our dynamic stent preserved effective compression of the posterior membrane in response to cough, and also provided lumen stability against extrinsic compression. In comparison, the two commercially available stents did not provide both functions equally well. In conclusion, our newly designed dynamic bifurcation stent shows characteristics which should prove useful in avoiding problems currently associated with airway stents.

Three years experience with a new balloon catheter for the management of haemoptysis

For the management of severe haemoptysis we have developed a double-lumen, bronchus-blocking catheter that can be introduced through the working channel of a standard fibrebronchoscope. We wondered whether this catheter would be suitable to control pulmonary haemorrhage in clinical practice. Over a period of 36 months, 30 of these catheters were used in 27 patients with moderate and massive pulmonary bleeding from various lesions. Underlying diseases were: malignancies (11), vascular deformities (5), tuberculosis (4), silicosis (2), carcinoids (2), silicosis (2), endometriosis (1), bronchiectasis (1). In 26 cases, the transbronchoscopic balloon tamponade was successful. In one patient, tumour growth close to the carina prevented securing of the balloon and double-lumen tube intubation was required. There were only minor complications attributable to the balloon. With the catheter in place for up to seven days, patients underwent surgery, received radiation, chemotherapy, drug treatment or bronchial arterial embolization. In conclusion, we found this double-lumen, bronchus-blocking device safe and the technique practicable to control pulmonary haemorrhage.

Theoretical and experimental basis for the development of a dynamic airway stent

Three major problems are currently associated with airway stents: mucostasis, formation of granulation tissue, and migration. We wanted to determine whether these problems could be solved by a different stent design. Based on theoretical considerations of an idealized trachea, we developed a dynamic bifurcation stent made of silicone which incorporates horseshoe-shaped steel struts. A flexible posterior membrane enables dynamic compression during cough, whilst the clasps maintain the airway lumen in the face of external compression. The design of the stent cast was based upon computed tomographic (CT)-scan studies of the central airways. Its complex shape provides a smoother distribution of pressure on the mucosa; thereby, lowering the stimulus for granulation formation. The bronchial limbs saddle on the carina, preventing displacement. The mechanical behaviours of the new stent and two commercially available stents were compared in an ex-vivo model, utilizing freshly excised tracheae and new visualization techniques. Dynamic (artificial coughs) and static loads (simulating tumour compression or pleural pressures) were applied on excised human tracheae with different stents. Our dynamic stent preserved effective compression of the posterior membrane in response to cough, and also provided lumen stability against extrinsic compression. In comparison, the two commercially available stents did not provide both functions equally well. In conclusion, our newly designed dynamic bifurcation stent shows characteristics which should prove useful in avoiding problems currently associated with airway stents.

Omentopexy and muscle transposition: two alternative methods in the treatment of pleural empyema and mediastinitis

From March 1987 to March 1993, 64 patients with chronic empyema and mediastinitis were treated with omentum and thoracic muscle transposition. There were 36 male and 28 female patients, age range 29 to 76 years. 31 patients suffered from chronic empyema and bronchopleural fistula after lung surgery, 18 patients had chronic empyema after pulmonary inflammatory disease, and 15 patients developed a mediastinitis with or without pleural empyema after cardiac surgery or irradiation of the chest wall. The pedicled omentum was used in 33, the thoracic muscles latissimus dorsi, pectoralis major, serratus anterior, and trapezius either alone or combined in 31 cases. There were no perioperative deaths. Bronchopleural fistulas and infected spaces were successfully closed in 61 patients (95.3%). Postoperative CT scan, angiography, bronchoscopy, and lung function tests demonstrate the efficacy of both surgical methods. Omentum pedicle and thoracic muscle flaps supply excellent vascularised tissue to fill infected pleural space and mediastinum, particularly in patients with limited cardiopulmonary function.