Faculty Bibliography

The relative sensitivities of different cancer histologies in a single site to photodynamic therapy (PDT) are unknown and methods to predict PDT sensitivity have not been described. The in vitro response to PDT of six established human lung cancer cell lines and one normal lung fibroblast cell line was studied using the clonogenic assay. Dose-response curves were determined for cells incubated in 25 micrograms/ml of Photofrin II for 2 h, followed by exposure to 630-nm light to total energies of 0-3150 J/m2. None of the cell lines were sensitive to sensitizer alone or light alone. Differences in inherent PDT sensitivities as evaluated by survival curve parameters n, Do, and light dose to yield 1% survival were observed among the cell lines. No clear correlation was found when inherent PDT sensitivity was compared with sensitizer uptake; however, a general association was noted between PDT sensitivity and the plating efficiency of the cell line. These data illustrate that differences in inherent PDT exist for in vitro systems. Such differences may explain some of the failures seen in clinical PDT

The frequency of atypical pathologic manifestations of Pneumocystis carinii pneumonia (PCP) were studied in 123 lung biopsy specimens from 76 National Institutes of Health patients with the acquired immune deficiency syndrome. The following atypical features were observed: interstitial (63%) and intraluminal (36%) fibrosis, absence of alveolar exudate (19%), numerous alveolar macrophages (9%), granulomatous inflammation (5%), hyaline membranes (4%), marked interstitial pneumonitis (3%), parenchymal cavities (2%), interstitial microcalcification (2%), minimal histologic reaction (2%), and vascular invasion with vasculitis (1%). These atypical features are discussed with emphasis on the significance of cavities, vascular invasion, vasculitis, and granulomas. Immunohistochemical staining with monoclonal antibodies to the 2G2 and 6B8 antigens of P carinii in paraffin-embedded lung biopsy specimens did not indicate any diagnostic advantage over routine methenamine silver stains. This study provides an important reminder that a wide variety of pathologic manifestations may occur in PCP in human immunodeficiency virus-infected patients and that atypical features should be sought in lung biopsies from patients at risk for PCP

The association of a bronchial or thymic carcinoid as a source for the ectopic production of adrenocorticotropic hormone (ACTH) has been reported since 1957, with approximately 72 cases in the literature. These patients are characterized by young age, long duration of Cushing's syndrome because of the inability to find the ectopic source, and a high incidence of hypophysectomy or adrenalectomy without curing the disease. A substantial number of patients, upon discovery of the thoracic ectopic source, are also found to have malignant carcinoid tumors with lymph node metastases. Fifteen patients have been explored for a presumed intrathoracic source of ACTH at our institution since 1983 and 14 carcinoids (13 bronchial, one thymic) have been resected. Seventy-one percent (10/14) of the patients appear cured with normal plasma ACTH levels 5 to 57 months after resection, despite a 50% incidence of positive lymph node disease. Management of these patients demands an aggressive evaluation to prevent unnecessary adrenalectomy or hypophysectomy and to allow earlier resections before these potentially curable malignancies metastasize. When the tumor is discovered, thorough exploration and complete lymph node mapping with resection must be performed

Indications for chest wall resection of metastatic or locally recurrent sarcoma and for subsequent bony reconstruction are controversial. Twenty-eight patients had chest wall resection for high-grade primary, metastatic, or recurrent sarcoma. In all patients, resection with selective reconstruction of the bony thorax was performed without operative mortality. Since 1980, only patients with four or more ribs resected have had selective bony reconstruction. Follow-up ranged from 8 to 132 months (median follow-up, 42 months). All deaths were related to sarcoma recurrence. The overall actuarial survival rate was 85% at 1 year, 65% at 3 years, and 59% at more than 5 years. The overall actuarial proportion without disease recurrence was 64% at 1 year, 52% at 3 years, and 40% at more than 5 years. There was no significant difference in overall or disease-free survival for patients with primary, metastatic, or recurrent tumors. The most important prognostic factors were positive margins and concomitant pulmonary resection for synchronous lung metastases. These data support aggressive resection to obtain pathologically tumor-free margins for chest wall sarcomas, whether primary, metastatic or recurrent. Reconstruction can be individualized based on the extent of resection

Thin-walled pulmonary cystic lesions were found in five immunocompromised patients, four with acquired immunodeficiency syndrome (AIDS). Four patients had Pneumocystis carinii pneumonia (PCP), and one had pulmonary lesions and disseminated P carinii infection. Two patients demonstrated P carinii within necrotizing, thin-walled, smaller intraparenchymal cavities lined by organisms, exudate, and chronic inflammation. Larger, typically apical and subpleural cysts, lined by fibrosis and/or alveolar parenchyma with little inflammation, were also found during acute episodes. The larger subpleural cysts can arise via rupture of intraparenchymal necrotizing cavities into the subpleural area. Pneumothorax in the four patients with AIDS could not be cured by close thoracostomy drainage; all required pleurodesis. The cysts persisted in cases that were followed up. All cysts were more obvious and numerous with computed tomography (CT), especially with 1.5-mm collimation. CT may be indicated in immunocompromised patients with unexplained pneumothorax or when tube thoracostomy has failed and surgery is being considered, as it can positively influence the operative approach

Photodynamic therapy (PDT) involves the treatment of tumors in the presence of sensitizer, light, and oxygen, causing energy-dependent cytotoxicity. A vascular effect that causes hemorrhagic tumor necrosis has been described with PDT, but its basis remains undefined. To investigate the possible role of tumor necrosis factor (TNF) production in the generation of such a vascular effect and/or a direct tumor effect, we treated thioglycollate-elicited murine macrophages with PDT, and we measured the possible production of TNF using the L929 assay. An energy-dependent production of TNF by macrophage treated with PDT, stimulated or unstimulated with endotoxin, was demonstrated, and TNF production was inhibited at the highest treatment energy levels. These data represent the first description of cytokine production by PDT-treated macrophages, and may serve as another mechanism of PDT cytotoxicity in vivo, either directly by TNF-mediated tumor necrosis, or indirectly by vascular effects on tumor vessels

Saline lavage of the major bronchial segments was performed in five patients immediately preceding lobectomy to remove an ACTH-producing bronchial carcinoid. Lavage fluid from each bronchus was concentrated, and ACTH determinations were performed. Elevated concentrations of ACTH were not demonstrated in the aspirate from the bronchus containing the known tumor. Two additional patients with ectopic ACTH syndrome from an unknown primary source also underwent selective segmental bronchial lavage for ACTH determination. Neither patient demonstrated ACTH gradients in the lavage specimens. One was found to have an ACTH-producing bronchial carcinoid 18 months after negative lavage. Selective segmental bronchoscopic lavage with measurement of ACTH levels on the aspirate is not an effective technique for detecting ACTH-producing bronchial carcinoid tumor

Allele loss is a hallmark of chromosome regions harboring recessive oncogenes. Lung cancer frequently demonstrates loss of heterozygosity on 17p. Recent evidence suggests that the p53 gene located on 17p13 has many features of such an antioncogene. The p53 gene was frequently mutated or inactivated in all types of human lung cancer. The genetic abnormalities of p53 include gross changes such as homozygous deletions and abnormally sized messenger RNAs along with a variety of point or small mutations, which map to the p53 open reading frame and change amino acid sequence in a region highly conserved between mouse and man. In addition, very low or absent expression of p53 messenger RNA in lung cancer cell lines compared to normal lung was seen. These findings, coupled with the previous demonstration of 17p allele loss in lung cancer, strongly implicate p53 as an anti-oncogene whose disruption is involved in the pathogenesis of human lung cancer